Family Felidae

Chapter 2

Family Felidae Chapter Outline Chapter 2.1 Classification The lineages Classification of the Felidae family Chapter 2.2 Evolution Chapter 2.2.1 The origins: the subfamily Proailurinae Evolution in teeth and development of the coronoid process Chapter 2.2.2 Subfamily Machairodontinae: phylogeny and classification Chapter 2.2.2.1 Tribe Metailurini Chapter 2.2.2.2 Tribe Smilodontini Chapter 2.2.2.3 Tribe Homotheriini Chapter 2.2.2.4 Tribe Machairodontini The Rancho La Brea fossil deposit Biology of Machairodontinae Chapter 2.2.3 The current Felides Chapter 2.2.3.1 Subfamily Pantherinae and lineage Panthera

13 17 20 20 23 25 26 28 29 30 31 33 34 40

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Chapter 2.1 Classification Carl von Linne´ is known more commonly as Carl Linnaeus (or Linnaeus) from the Latinized form of his name, Carolus Linnaeus (Ra˚shult, May 23, 1707
Uppsala, January 10, 1778). He was a Swedish physician, botanist, and naturalist, considered the inventor of the modern scientific classification of living organisms. In 1735 and then again in 1758 he published his famous Systema naturae, for Regna tria naturae secundum (systematice proposita per) for Classes, Ordines, Genera, Species (. . .), with which he founded the foundations of modern systematics, inventing the binomial nomenclature (with genus and species), assigning a universally valid scientific name to every living organism then known. This is why he is recognized as the “father of modern taxonomy.” He also classified the representatives of the then known family Felidae, such as the lion, tiger, ocelot, leopard, jaguar, lynx, and the domestic cat and, wanting Felines of the World. DOI: https://doi.org/10.1016/B978-0-12-816503-4.00002-7 © 2020 Elsevier Inc. All rights reserved.

Chapter 2.2.3.2 The occurrences of Panthera blytheae and Its importance in chronological dating of Pantherinae 42 Chapter 2.2.4 Subfamily Felinae 46 Felinae Lineages 47 Chapter 2.3 Anatomical features of current Felids 49 Skeleton and muscles 50 The skeleton (skeletal system) 50 The legs and retractable claws 52 The skull 55 Dentition of current Felides 57 The function of the teeth 58 Musculature (muscular system) 61 Cats always land on their feet 62 The fur 64 Furs: patterns, colors, and habitat 68 Fur as a protection from cold 69

to give them a taxonomic arrangement based on common anatomical features, he gathered together all these species under one genus Felis (from the Latin felis 5 cat), taking into account some features of the teeth and the retractile nails, and considering these typical peculiarities to be common to the entire genus. He then assigned some species to the genus Felis, describing for each of them some characteristic distinguishing features that enabled their recognition: Felis leo: long “floccosa” tail, which means having a bow (tuft) of terminal hairs, body yellow-red (Luteo rufus), and the male with a shaggy thorax (with a mane); Felis tigris: streaked body; Felis pardus: spotted body; Felis lynx: short tail with a black tip, ears with tufts of hair on the tip, spotted reddish color.

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Two original pages, 41 and 42, of “Systema naturae” edited 1735
58 of Carolus Linnaeus, written in Latin, the official language of science until the end of the 18th century. The taxonomic classification of the family Felidae (Mammalia Ferae: Felis) and of some of the then known species are illustrated; on page 41 are the lion, tiger, leopard, on page 42, the jaguar (Onca), ocelot (Pardalis), domestic cat (Catus), and on page 43 the lynx, with the specific anatomical features. https://upload.wikimedia.org/wikipedia/commons/a/a2/Sistema_Naturae_%281758%29.pdf

Following the Systema Naturae, for a few centuries all felids were grouped under the same genus Felis, given the many anatomical similarities that, beyond their body size, make the family seemingly very homogeneous. Even in the 20th century, an important text on African mammals (Kingdon, 1997) still brought together all the small felids (including the serval, caracal, and African golden cat) in the genus Felis. The cheetah, due to its particular anatomical features, was assigned to a new genus, Acinonyx (Brookes, 1828) and separated into a subfamily of its own: Acinonychinae (Pocock, 1917). Only at the start of the 20th century were the larger Felid species (lion, tiger, jaguar, leopard) divided into their new genus: Panthera. Due to its large size, the puma was assigned to both the genera Felis and Panthera, by different authors; the caracal, because of its short tail and tufts on the ears, was also assigned to the same group as the lynx (lynx caracal) and was sometimes called the desert lynx. The increase in anatomical knowledge resulted in the genus Panthera being merged into a subfamily, that of

Panterinae, which gathered all the species that could roar, a possible feature because of the hyoid bone, which in this genus was not completely ossified but maintained a fibrous front and ligaments that allowed some mobility of the larynx. All the other cats (classified as the Felis genus), ascribed to the subfamily Felinae, instead had the ossified bone completely ossified so that the larynx was blocked, preventing the ability to roar but allowed them to “purr,” with this latter capacity not being present in the Panterinae. However, with the advancements in the anatomical knowledge of the vocal apparatus of the Felidae, even this definition was questioned, because it was seen that not all big cats could roar, resulting in snow leopards being ascribed for a long time to a different genus (Uncia). It was also discovered that the clouded leopards (Neofelis), although true panthers, had a rigid and ossified hyoid bone and did not roar (in Chapter 7: Ethology, we will see that the roar is also linked to the structure and the dimensions of the “vocal folds” and of the thorax that acts as a sounding board). Also in the subfamily of the Felinae (small cats),

Family Felidae Chapter | 2

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The watchful and intense look of a lioness. Initially Linnaeus grouped all the species of felids into a single genus Felis. The lion was initially named Felis leo (1758) until the German naturalist Lorenz Oken in 1816 proposed the separation of the Big cats in the new Genus Panthera. https://upload. wikimedia.org/wikipedia/commons/c/c5/African_lion%2C_Panthera_leo_at_Kgalagadi_ Transfrontier_Park%2C_Northern_Cape%2C_South_ Africa_%2834637888921%29.jpg

the problems of taxonomic classification were numerous, and before the advent of modern techniques of genetic and biomolecular analysis, studying the comparative anatomy, especially the skulls and colors of the fur of the various species, the Felis genus, was subdivided into many genera, which were not always accepted later, although some are still considered valid, including: Leptailurus for serval, Otocolobus for manul, Herpailurus (Puma) for jagouarundi. Especially in the new species that were being discovered and classified, and particularly within the group of small felids of South American and Southeast Asia, there was an explosion of new genera, with a new one for almost every species. Other new genera included the following: G

G

South America: Lynchailurus for the pampas cat or colocola, Oreailurus for the Andean cat, Oncifelis for the guigna (or kod-kod) and Geoffroy’s cat, Oncilla for the tiger cat, and Leopardus for the ocelot and margay. Asia: Prionailurus for the Asian leopard cat (and related species such as the fishing cat), Otocolobus for the manul or Pallas cat, Catopuma for Temmink’s cat and the Borneo bay cat, and Pardofelis for the marbled cat.

For some time the temminck’s cat or Asian golden cat and the African golden cat, given their obvious external similarity (especially for color and body proportions) were brought together in the genus Profelis, which is no longer used for either species, however molecular analysis revealed them to have no proven affinity; in fact, the African Golden Cat has been classified since as Caracal aurata and is in the same lineage as the caracal and serval; while the Asian golden cat has shown affinity with the lineage of the Borneo bay cat. Today, all the small cats of the South and Central America are brought together in the genus Leopardus, because, after much research, the absolute affinity between these species has been verified, especially after the recent interbeeding discoveries (current and ancient) between more or less sympatric species (or with neighboring areas), as happened with Leopardus tigrinus, Leopardus guttulus, Leopardus geoffroyi, and Leopardus colocola (Eizirik et al., 2013). It seems that the diversification at the specific level (speciation) of northern oncilla (L. tigrinus) has been favored by an ancient hybridization with another South American species, the Pampas cat (L. colocola). Currently, however, there is active

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hybridization between the Geoffroy’s cat (L. geoffroyi) and the southern oncilla (L. guttulus) in southern Brazil where the distribution areas of these two species largely overlap. The latest scientific journals, based on new techniques of genetic analysis of the chromosomal DNA, DNA and mitochondrial genes (Mitogene), molecular phylogeny, the molecular clock, and estimating species divergence, have shown how these ancient hybridizations between related species are present in the genome of many of the current feline species (Li et al., 2017). For this reason it will still take many years of in-depth

studies to obtain a definitive taxonomic classification of the family of the felids and also to obtain scientifically safe phylogenetic trees. However, compared to only a decade ago, great steps have been taken, with the help also of the new paleontological findings of important fossil Felids, such as Panthera blytheae in Tibet (Tseng et al., 2013), Puma pumoides and Puma concolor in South America (Chimento et al., 2014; Chimento and Dondas, 2017), which are among the most significant discoveries that have been made in recent years to clarify the evolutionary history of Felinae and Pantherinae.

*Today many authors consider a greater number of species, up to 41, because they include another four valid species: Leopardus guttulus—Southern oncilla, recently separated (split) from the northern oncilla (Leopardus tigrinus); Prionailurus javanensis—Sunda leopard cat, recently separated (split) from the Asian leopard cat (Prionailurus bengalensis); Felis lybica—African-Asian wildcat, no longer considered a subspecies of the European wildcat (Felis silvestris); Felis bieti—Chinese mountain cat, no longer considered a subspecies of the European wildcat (Felis silvestris). O’Brien, J.S., Johnson, W.E., 2007. The evolution of cats. Sci. Am. 68
75. http://www.bio-nica.info/biblioteca/O’brien2007EvolutionCats.pdf described by Scientific American.

Family Felidae Chapter | 2

The lineages In 1985 Collier and O’Brien (A Molecular Phylogeny of the Felidae: Immunological Distance) began to study this family from the point of view of molecular biology and used the concept of “lineage” to indicate a group of species from the same phylogenetic (evolutionary) branch. In 2006 a group of geneticist and zoologist researchers, Johnson, Eizirik, Pecon-Slattery, Murphy, Antunes, Teeling, and O’Brien, published in the journal Science the results of an important genetic research on felids: The Late Miocene Radiation of Modern Felidae: A Genetic Assessment. They attempted to reconstruct the phylogeny of all species of the family, by analyzing the DNA of 38 species of felines and comparing these with those of other species of Carnivora. The species were divided into eight groups, each of which represented a lineage. Each lineage unites species with similar anatomical-genetic characteristics because they belong to the same evolutionary line and share common ancestors (with well-documented fossil evidence or only hypothesized through biomolecular analyses) from which current species have evolved. According to the chronology proposed by Johnson et al., the most ancient felids are the subfamily Pantherinae with only one lineage: 1. B10.8 Mya, lineage Panthera, with the genus Panthera and Neofelis Hereafter, the lineages of the subfamily Felinae originated, in succession:

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2. B9.4 Mya, lineage Bay cat, with the genera Catopuma and Pardofelis 3. B8.5 Mya, lineage Caracal with the genera Caracal and Leptailurus 4. B8 Mya, lineage Ocelot with the genera Leopardus 5. B7.2 Mya, lineage Lynx with the genera Lynx 6. B6.7 Mya, lineage Puma with the genera Acinonyx and Puma from which it is often distinguished by Herpailurus 7. B6.2 Mya, lineage Asian leopard cat with the genera Prionailurus and Otocolobus 8. B3.4 Mya, lineage Domestic cat with the genera Felis. According to Li et al. (2016) the chronology and therefore the previous sequence must be corrected according to this scheme (see Fig. below): 1. B11.5 Mya, lineage Panthera 2. B10.67 Mya, lineage Caracal 3. B9.5 Mya, lineage Ocelot For these authors, the lineages Lynx and Bay cat have a common origin and they share their ancestors from about 8.5 up to 7.5 Mya when they separated definitively, subdividing into the two current lineages: 4. 5. 6. 7. 8.

B8 Mya, lineage Puma B7.5 Mya, lineage Lynx B7.5 Mya, lineage Bay cat B7 Mya, lineage Asian leopard cat B4.23 Mya, lineage Domestic cat.

Comparison between philogenetic tree with the current species of the lineages of Felidae family across different types of genetic analysis. Li, G., Davis, B.W., et al., 2016. Phylogenomic evidence for ancient hybridization in the genomes of living cats (Felidae). Genome Res. https://pdfs.semanticscholar.org/8e88/1da6db0d72387762bf7912b84b35c0d43c1e.pdf.

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The important and current series of phylogenetic tree (phylogenetic diagrams) shows the different results and discrepancies in the positioning of the various lineages, and related species, obtained according to different genetic analyses. The causes of such divergences can be attributable to hypothetical ancient hybridizations that have occurred between related species. Such interbreeding could also be one of the causes of the diversification of some species, as seems to be currently taking place, for example, in some species of the South American genus Leopardus. (A) Phylogenetic patterns are discordant according to the inherited type of subgenoma: maternal (matrilineal or mitochondrial), paternal and biparental, or nuclear genome. Left: Phylogenetic tree obtained through the analysis of the biparental nuclear genome (paternal and maternal). Right: Phylogenetic tree obtained through analysis of the “mitogenome” or mitochondrial genome (matrilineal). By comparing the two trees the highlighted differences are the different positionings of particular species (black lines) or whole clades (red lines). The black dashed lines represent different positions of species not sufficiently demonstrated. The divergence times indicated for the various lineages and related species are proposed by calculating with statistical methods through a comparison of the most reliable data obtained from various researches. The lineages are color coded according to their current and/or historical distribution area (see planisphere with the various colored continents). In the left diagram the dotted lines indicate dispersion events hypothesized outside Eurasia (in green and considered the center of origin, differentiation and diffusion of most species of the Felidae family). The gray vertical bars indicate periods in which the extent of low sea level areas (Haq et al., 1987) may have favored the union of islands and continents through land bridges, and thus facilitated the dispersion of various taxa between different continents and current islands (e.g., Bering bridge, isthmus of Panama, isthmus of Kra, and Sunda Islands). (B) Four different phylogenetic diagrams obtained with four different methods of genetic inheritance analysis: From the left: The first is based on the analysis of mitochondrial DNA (matrilineal); The second shows results obtained with analysis of sexual chromosome X; The third shows results obtained with autosome analysis (nonsexual chromosomes); The fourth shows results obtained with analysis of the Y-chromosome.

The lineage Bay cat is shown in bold to highlight the great diversity of positions taken in the charts based on the different inheritance modes analyzed. Other drastic changes to the time-calibrated phylogeny regarding the Pantherinae have been proposed by paleontologists (Tseng et al., 2014), who have found fossils of P. blytheae in Tibet. This is the oldest Panterino fossil (having affinity with the snow leopard), which dates back to between 4.5 and 5.9 Mya. Taking into account that the oldest known Pantherinae fossil was the so-called Lion or Feline of Laetoli (Tanzania) dated 3.6 Mya, the authors of the discovery of the new fossil, proposed a few million years receding all the dates of the Pantherinae phylogenesis, backdating (leaving however wide margins of probability of variation) to about 16.4 Mya the separation between the ancestors of the genus Panthera and the genus Neofelis, and to 10.7 Mya the appearance of the genus Panthera and the beginning of the subdivision in both fossil and current species (the history of this fossil discovery, of its characteristics, and the consequences on the calculation of the Pantherinae biological clock is discussed in depth in Chapter 4: Subfamily Pantherinae). Finally, regarding the classification of the species of living Felids and their taxonomy, that is the subdivision into genus, species, and subspecies, in 2017 a group of 23 world experts of felids2 founded the Cat Classification Task Force of the IUCN/SSC Cat Specialist Group and published A Revised Taxonomy of the Felidae: The Final Report of the Cat Classification Task Force. Today it is the most up-to-date proposal for the classification of the subfamilies Pantherinae and Felinae, and of the current species of living felids. According to this study/revision, accepted by almost all experts, the current subdivision of current felids is proposed as: 2 subfamilies, 8 lineages, 14 genera, 41 species, 77 subspecies. This new taxonomic proposal will be the pattern we will follow for the description of species in this book, however it seems proper not to neglect the treatment of some “historical” subspecies that are well known and often recognizable phenotypically, even if today they are no longer considered genetically acceptable, for example, the famous “Siberian tiger” that we currently consider as only a geographical variant or “Siberian population of the royal of Bengal or Continental tiger” Another interesting example is the Iriomote Island cat, the subject of many studies but which is no longer recognized even as a subspecies (Prionailus bengalensis iriomotensis) but only as a probable result of an anthropic importation to the small Japanese island of some specimens

2. Kitchener A. C., Breitenmoser-Wu¨rsten Ch., Eizirik E., Gentry A., Werdelin L., Wilting A., Yamaguchi N., Abramov A. V., Christiansen P., Driscoll, C., Duckworth J. W., Johnson W., Luo S.-J., Meijaard E., O’Donoghue P., Sanderson J., Seymour K., Bruford M., Groves C., Hoffmann M., Nowell K., Timmons Z. & Tobe S. (2017). A revised taxonomy of the Felidae. The final report of the Cat Classification Task Force of the IUCN/SSC Cat Specialist Group. Cat News Special Issue 11, 80 pp.

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of feral Asian leopard cat; although this cat was even coined its own genus, Mayailurus iriomotensis, it is no longer recognized either genetically or taxonomically. Neither are the proposals of new species that result from very current and in-depth studies done by Fabio O.

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do Nascimento et al. in 2017, on behalf of important Brazilian Universities and Research Institutes, with the collaboration of the Field Museum Natural History of Chicago, on South American cats and especially on Leopardus tigrinus.

The graph shows, from a chronological point of view, one of the hypotheses of the birth of the eight groups (lineages) of felids and how long the various species that we know today have been present on Earth without undergoing obvious changes to their genotype or phenotype (genetic and anatomical). As can be seen, the most ancient species is the manul or Pallas cat, which originated between 6 and 5.9 Mya, followed by the serval, which dates back to 5.6 Mya and the marble cat of 5.41 Mya. https://www.bbc.com/news/magazine-28795301

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Classification of the Felidae family According to recent systematic reviews, the Felidae family is comprised four subfamilies: G

Two, the Proailurinae (origin of all Felidae) and Machairodontinae, both now extinct, and known only through fossilized skeletal remains, such as the famous saber-toothed cats. Another two, the Pantherinae and Felinae, include all currently known living species and the extinct fossil species related to them (cave lion, American lion, European jaguar, etc.)

G

The Proailurinae (genera Proailurus, Pseudaelurus, Styriofelis) are not universally considered to be the true

ancestors of the Felidae family, and as components of a distinct subfamily, and appeared at the end of the Oligocene. According to some researchers (Piras et al., 2013) the family Felidae (one of the five monophyletic groups of cat-like carnivores or Feliformia) has instead two subfamilies, Machairodontinae and Felinae, to which are added a clade (taxa not named) composed of the genera Hyperailurictis and Nimravides (this last genus should not be confused with the family Nimravidae which is not part of the Felidae) and a sister group of the Felinae composed of the genus Styriofelis. According to this taxonomic proposal, Pseudaelurus quadridentatus would be part of the Machairodontinae and Proailurus lemanensis is considered the basal taxa of the whole family Felidae.

Classification Family of Felidae Fossil original subfamily of Proailurinae † † Subfamily extinct, with species living from about 35/28.4 Mya (latter Oligocene) to 10 Mya Genera:Proailurus, Pseudaelurus, Styriofelis with more species; Styriofelis vallesiensis has recently been separated into a new genus Leptofelis vallesiensis They are considered true felids only by some authors, while others consider them as ancestors but not yet felids Subfamily of Pantherinae Current subfamily 16.4/10.8 Mya to present seven species and two genera: Panthera and Neofelis

Subfamily of Felinae Current subfamily 12.5/10.67 Mya to present 34 species and 12 genera: Acinonyx, Puma, Herpailurus,a Lynx, Prionailurus, Leopardus, Otocolobus, Pardofelis,bCatopuma, Caracal, Leptailurus,cFelis

Fossil subfamily of Machairodontinae † Extinct subfamily lived from 22
18 Mya to 11,000 years ago B15 genera and many species, among which are Smilodon, Machairodus, Megantereon, Homotherium, Dinofelis, Xenosmilus, etc.

Tiger, lion, leopard, snow leopard, jaguar, Indochinese clouded leopard, Sunda clouded leopard

Cheetah, puma, lynx, ocelot, serval, and all the other real small wild cats

Saber-toothed cats, scimitar-toothed cats

These have a hyoid bone with the fibrous front and with elastic ligaments; they roar, even if not all can

These have the hyoid bone completely ossified; they do not roar but, mostly, meow and they are able to purr

These are called saber-toothed or scimitartoothed cats, due to their long upper canines that protruded from the jaws, like long tusks

In Neofelis the hyoid bone is completely ossified as in the Felinae subfamily

Smilodon populator was perhaps the largest feline that never existed

a

Some authors maintain that the jagouarundi is in the genus Herpailurus and not Puma. Some authors consider the only one genus, Catopuma, but others attribute the marble cat to the genus Pardofelis. Many authors maintain that the serval is in the genus Leptailurus.

b c

Chapter 2.2 Evolution Perhaps more than 35/28.4 Mya [24/20 according to the latest estimates by Barnett et al. (2017)], carnivorous species appeared that could be considered the true progenitors of the current felines (order Carnivora, family Felidae); these forms have been brought together in the

most primitive subfamily of the Felidae: the Proailurinae. They began their “evolutionary history” by dividing into various taxa. About 20 Mya the Proailurinae began a separation into two main lines of evolution, with the appearance of the genera Styriofelis and Pseudaelurus, which gave rise to a great explosion in the forms from which on one side were the manifold

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species of the subfamily Machairodontinae or sabertoothed cats, with a tribe Homotherini, and Smilodontini who separated about 18 Mya (Burnett et al., 2017); these predators dominated many environments for millions of years and reached total extinction only about 11,000 years ago. Another evolutionary line led, starting from 16/10.8 Mya, to the current Pantherinae and Felinae subfamilies, whose species are transformed, adapting to changes in the different climatic-ecological situations and evolving into the species that currently live and coexist with us on most continents. Some of these species have become the main predators of many of the

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current terrestrial ecosystems: prairies and savannas (lion, cheetah), deserts (sand cat, caracal, and others), mountainous areas (snow leopards), to the various types of forests of tropical climates (jaguar, leopard, many small felids such as ocelot), temperate forests (puma), and coniferous forests of the cold boreal regions (Eurasian and Canadian lynx). The felines are, among the carnivores, those most specialized in hunting, with a body structure perfectly adapted for predation and with a diet exclusively based on protein, that is, meat; for this reason, within the order of the carnivores they are separated into a group called “hypercarnivorous.”

A in the diagram indicates that the small Proailurus of Eurasia, about 30 Mya and the size of a genet, is considered by many authors to be the first true feline, from which the Felidae family originated; first appeared (A
B
C
E) with the Proailurinae (Proailurus, Pseudaelurus, and Styriofelis) from which the extinct Machairodontinae (E
F
J, etc.) and the current Pantherinae and Felinae (C) evolved. According to Werdelin et al., in Macdonald, D.W., and Loveridge, A.J. (2010), Biology and Conservation of Wild Felids, Oxford University Press Book, Fig 2.2, Pag. 62.

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THE MAIN EVOLUTIONARY LINES OF THE FAMILY FELIDAE Eocene

†Proailurinae

Oligocene Proailurus (lemanensis, etc.) From 30/28 to 17 Mya

Upper Miocene

Middle Miocene

Lower to Early Miocene

Styriofelis (lorteti, etc.) Leptofelis vallesiensis From 22 to 9 Mya

Pantherinae From about 16 –10.8 Mya, to today

Pliocene Pleistocene Olocene

Pseudaelurus (quadridentatus, etc.) From 20 –18 to10–8 Mya

†

Felinae From about 11.5/10 Mya to today

Puma

Machairodontinae

From 18 Mya to11,000 years ago

Homotherium

Lion

Black jaguar

Snow leopard Lion, tiger, leopard, jaguar, snow leopard, clouded leopard

Saharan cheetah

Ocelot Wild cats, puma, cheetah, lynxes, caracal, serval, ocelot, manul, etc.

Present Extant

Extant

Drawings courtesy of Terryl Whitlatch, Mauricio Anton, and Artem Holubiev.

Smilodon

Lokotunjailurus Saber- and scimitar-toothed cats, Smilodon , Homotherium, Dinictis, Megantereon, etc.

† Smilodon until 11,000 years ago † Homotherium until 14,000 years ago

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Chapter 2.2.1 The origins: the subfamily Proailurinae The earliest forms from which the current felids descended belong to fossil species of the Proailurus genus which lived in Eurasia from about 30 to 20
22 Mya (from the Oligocene up to the ancient Miocene) and which were about the size of a domestic cat or a genet. From these derive the more recent Pseudaelurus, which lived from about 20/18 to 10/8 million years ago with about 10 species brought together in a Eurasian-Arab group and a North American group; they were the size of a lynx or small puma with an elongated trunk and somewhat short limbs similar to those of some Viverrids. Some authors (Wesley-Hunt and Flynn, 2005) place

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Proailurus outside of the Felidae, while McKenna and Bells (1997) consider them to belong to the Felidae and place them in the subfamily Proailurinae, however this has not been unanimously accepted; for example, Meloro et al. (2008) and Rothwell (2003) classify these genera as “incertae sedis.” More recently a group di species of Proailurus has been separated by including both Styriofelis and Leptofelis, from which the current felids (Pantherinae and Felinae) would derive; while Pseudaelurus species would instead be the progenitor of Machairodontinae, the famous ones sabertoothed cats, now extinct, but whose last representatives, such as Smilodon populator, is survived up to 11,000 years ago in South America.

A reconstruction of Proailurus lemanensis, the first true feline, which had an arboreal lifestyle.

Early Proailurinae belonged to very arboreal species but, in 2012, while studying the fossil remains in the Spanish late Miocene locality of Batallones-1, M. Salesa et al. discovered the remains of a cat named Styriofelis vallesiensis. In 2017, after a more careful analysis, these remains were identified as belonging to a species with more slender legs than the other Styriofelis, which suggested a

greater predisposition to fast running rather than climbing, and for this reason the Spanish paleontologists attributed the remains to a new genus, calling it Leptofelis (meaning swift felis) vallesiensis. Compared to other species of Styriofelis (turnauensis and lorteti), the new genus was more similar to the first wild cats of the genus Pristifelis that, like Leptofelis, had thin legs suitable for running.

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Reconstruction of the skeleton of Leptofelis vallesiensis with the fossil remains found in the Spanish site of Bataillones-1. Compared to the cats of the time (Styriofelis) this specimen presents leg bones that are proportionally longer and thinner, which lead us to assume a greater cursorial ability. Courtesy Mauricio Anto`n.

Reconstruction of the fossil skeleton of Proailurus lemanensis, whose remains date back to the Oligocene and are found in Eurasia; the most complete set was found in France. It has characteristics that still bind it to Viverridae like the current Cryptoprocta ferox, the “fossa of Madagascar,” which indicate it must have had arboreal habits Height 38 cm

Courtesy of Mauricio Anto`n.

Pseudaelurus (Schizailurus) reconstruction, this species of the genus probably lived in tree-lined habitats and were excellent climbers These real cats, with similar dimensions to a lynx, nevertheless presented shorter limbs than modern felids (especially the metacarpals), and this made them similar to their predecessors, with appearances akin to the former Viverridae Height 48 cm

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Skeleton (A) and Reconstruction (B) of Styriofelis lorteti, based on the fossil-skeletal findings at Sansan (France). Compared to current felidae, shorter and more robust legs are seen, especially metapodials (bones of the hands and feet) that are shorter than in current felines. This leads to a less running skill and a greater predisposition to an arboreal nature, as in some current felids (clouded leopard, margay, marbled cat). The large spots in the fur are consistent with the phylogeny of colors, which considers hair in large patches as the most primitive pattern type in Felidae fur. Courtesy Mauricio Anto`n.

Evolution in teeth and development of the coronoid process Among all carnivores, modern felids have the lowest number of teeth. In fact, among the felids the loss of some mandibular teeth (premolars and molar) represents a secondary and successive adaptation, which has happened gradually. The older fossil species, such as the Pseudaelurinae, have a greater number of teeth, and with the passage of time we see the gradual loss of molars and

premolars as an adaptation for greater effectiveness in killing prey. In fact, the shortening of the mandible and the development of the coronoid process allow, on the one hand, use of strong chewing muscles (temporal and masseter), and on the other hand a short-arm lever mechanism, which results in a greater biting power. Therefore we can see whether a fossil of a felid tooth is preceding or following another by observing both the number of teeth, which is minimal in most current species, and the size and development of the coronoid process of the jaw.

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The fossils of the first ancestors of felids, Proailurus, are recognized because they have a greater number of mandibular teeth than current felids: in each hemimandible (lower) there are three premolars: the 2nd (or Pm2), the 3rd (or Pm3), and the 4th (or Pm4) and two molars: the 1st (or M1) and the 2nd (or M2). In addition, the mandibular bone is more elongated and less robust than in most current species Dental formula Inc 33 =Can 11 =Pm 32 =Mol 2 12 5 Tot 34

Pseudaelurus fossils, which are more recent and evolved compared to Proailurus, have retained the premolar 2 degrees (or Pm2), but have lost the molar 2 degrees (or M2). For this we note a slight shortening of the lower jawbone or mandibular bone Dental formula Inc 33 =Can 11 =Pm 33 =Mol 2 11 5 Tot 32

Mandible drawing from Tom Rothwell (2003). Phylogenetic systematics of North American Pseudaelurus (Carnivora, Felidae). American Museum novitates 3403: 1
64.

Previously classified as Styriofelis vallesiensis, this true ancestor of the current felids, after extensive studies by Salesa et al. (2017), has been reclassified as Leptofelis vallesiensis. Having also lost the 2nd premolar, it has a mandibular dentition similar to the felids despite the mandibular bone being slightly elongated, the coronoid process of the mandibular bone is already well developed. Dental formula Inc 33 =Can 11 =Pm 32 =Mol 2 11 5 Tot 30

Chapter 2.2.2 Subfamily Machairodontinae: phylogeny and classification All extinct forms of saber-toothed, scimitar-toothed, and dirk-toothed cats belong to the subfamily Machairodontinae. These generally varied in size from that of a lynx up to that of a lion, but many reached even greater sizes, with S. populator (400 kg) probably being the largest wild felid ever to exist. All had pointed and procumbent incisors (tilted forward) and well-developed canines, but some were equipped with impressive canines longer than 15
20 cm and shaped like a saber or scimitar, with a round or flattened side section and a serrated edge;

The decrease in the number of mandibular teeth (premolars and molars) together with the shortening and strengthening of the mandibular bone, with a well-developed coronoid process, is an important evolutionary line that has led to the current felids, which today only have 28/30 teeth. In each emi-mandibule there are always only two premolars (the 3rd, or Pm3, and the 4th, or Pm4) and only one molar (the first or M1). Sometimes in the upper jaw there is the premolar 2 degrees (or Pm2), the earlier one, which is always very small and in many species is always missing (lynxes), while in other species it is always present, and in some species it may be present or absent (e.g., in Leopardus colocola, according to A. Barstow, D. Leslie, 2012). 1 Dental formula Inc 33 =Can 11 =Pm 2ð3Þ 2 =Mol 2 1 5 Tot 28=30

in many species these tusks protruded from the mouth far past the chin. Another common feature was the glenoid fossa (of the scapula to accommodate the head of the humerus), which was shallow and very low. Many sabertoothed cats had a massive structure with a large head with a protruding snout, supported by an elongated and very muscular neck; the front of the body had a powerful ribcage and long, massive front legs supported by bones (humerus, radius, and ulna) that were extraordinarily robust. The hind legs were strong but shorter than the front ones, which created a dorsal backbone line, as in current hyenas. The tail was almost always short.

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https://upload.wikimedia.org/wikipedia/commons/3/32/Smilodon_populator_skeletal.jpg. Courtesy Museum Natural History Pisa.

They differed from current felines and panterini as the tympanic bulla did not originate from two different bones and was not divided by a septum (Neff et al., 1991), they also had much stronger and larger feral teeth than any current big felidae. There are many disagreements about their origin and the estimated times proposed on the period of their appearance change continuously, being greatly expanded with the latest paleontological discoveries. One theory gives their origin at around 23 million years ago with a phyletic line that starts from P. quadridentatus in Africa, however, according to other theories their appearance and development began in Europe about 15
14 Mya (Loveridge and Macdonald, 2010), while according to Barnett et al. (2017) their story began between the end of the Oligocene and the start of the Miocene (more than 24 Mya) with the Metailurini tribe (Metailurus, Dinofelis). Until a few years ago it was hypothesized that the first transition between Proailurus and Machairodontinae may have been Miomachairodus pseudailuroides, of which we only have remains in Turkey and China. Today, however, this genre is considered a subgenus of Machairodus, whose remains we find also in Eurasia and North Africa. The Metailurini could therefore be the first saber-toothed cats, from which two lineages separated, one leading to Machairodus afanistus (5Amphimachairodus giganteus), Xenosmilus, and Homotherium; with the other lineage leading to the formation of various genus of the Smilodontins, such as Paramachairodus, Megantereon, and finally Smilodon. Hence these forms of Machairodontinae spread

throughout Eurasia, Africa, and especially the Americas, with about 10
15 genera (many more according to Piras et al., 2018) and many species, some of which, such as S. populator and Homotherium latidens (5serum?), survived, respectively, up to about 11,000 and 14,000 years ago, and for a time coexisted with our human ancestors who probably had to defend themselves from them. For many millions of years the Machairodontinae were the most important predators in many ecosystems, both warm and northern/cold climates, and the larger species (Smilodon, Homotherium,) were able to hunt huge prey including proboscideans and woolly rhinos (perhaps only the young), giant sloths, and huge species of primitive bison and horses. More for practical reasons than for an effective correct phylogeny, they are divided according to their characteristics into four tribes, perhaps in order of appearance: Metailurini (possibly paraphyletic), Machairodontini, Homotheriini, and Smilodontini, although these are sometimes reduced to three, as not all accept the Machairodontini tribe, merging them with Homoteriini (or merging the Homoteriini with the Machairodontini). Christiansen (2013) and other researchers, however, reject this simplified phylogenesis with a classification in tribe, and think that the phylogenesis of feline sabertoothed cats is more complicated and so introduced another group, Eumachairodontia, in which they bring together two evolutionary lineages—the genus Smilodon together with the Homoteriini, and in another lineage three species of the genus Meganthereon.

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White strips represent the known fossil record for each taxa globally, black lines are the fossils recorded in South America, and the numbers on the nodes represent the DNA divergence dates in millions of years. The graph shows that Machairodontinae appeared between the late Oligocene and early Miocene. Modified by Rincon, A.D., Prevosti, F.J., Parra, G.E., 2011. New Saber-Toothed Cat Records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange. J. Vertebr. Paleontol. https://www.jstor.org/stable/25835839?seq=1\lpage_scan_tab_contents; https://www.jstor.org/stable/25835839?seq=1#page_scan_tab_contents/; https://bioone.org/journals/Journal-of-VertebratePaleontology/volume-31/issue-2/02724634.2011.550366/New-Saber-Toothed-Cat-Records-Felidae–Machairodontinae-for-the/10.1080/ 02724634.2011.550366.short?tab=ArticleLinkFigureTable

Chapter 2.2.2.1 Tribe Metailurini These are nonhuge species the size of a puma or lynx. The oldest, such as Adelphailurus and Yoshi, were the size of a large lynx (about 30/50 kg) with a fairly light structure, elongated limbs, and not very long canines, similar in section to those of the current felids. They were widespread in Eurasia and North America, from perhaps more than 20 Mya up to the middle Pleistocene. Another lineage included Dinofelis of very ancient origin but with fossils found dating from 5 to 1 Mya, and Metailurus;

these both have the dimensions of a puma or a leopard; the second lived from 9 Mya perhaps up to the middle Pleistocene (130,000 years ago) with fossils also found in Africa. Their structure was rather slender, and the canines were not too developed, making them similar to today’s Felini, so that some authors consider these fossils to be the same subfamily of Pantherinae and call them “false saber-toothed cats.” Not all researchers currently consider this tribe to be valid (as it may be a paraphyletic group).

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Two Metailurini with slightly more developed canines than those of the current Felidi, to which they are sometimes related. (A) Reconstruction of Metailurus parvulus. (B) Skeleton reconstruction of Metailurus major. Drawing courtesy Mauricio Anto`n.

Chapter 2.2.2.2 Tribe Smilodontini This includes two lineages: an older Eurasian (Promegantereon and Paramachairodus, which lived from 20 to 9 Mya) of small size (about 50 kg), and another, more recent, which includes Megantereon which lived about 18 Mya but with fossils from 6 Mya to 500,000 years ago, perhaps first spread in North America and then in Eurasia and Africa with some larger Asian species, and reached the size of a lion (120 kg). Another famous genus

of this lineage is Smilodon, the saber-toothed cat par excellence with at least three species: S. gracilis, the smallest, S. fatalis, a little larger and well known for the large number of fossils found, and S. populator, the largest, which lived in North and South America; this lineage separated from the genus Homotherium 18 Mya (Barnett et al., 2017) and lived up to 11,000 years ago. They had a very massive structure and skull with tusks more than 20 cm long but flattened sideways.

A skeleton of a Smilodon populator fossil record dating from the Late Pleistocene of Rio Areco in Argentina and exhibited in the Natural History Museum of Wien. Courtesy Natural History Museum of Wien (photo by A. Schumacher).

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Smilodon populator reconstruction. This species is probably the largest of the felids that ever existed, reached 400 kg in weight and a shoulder height of 1.20 m. It lived up to 11,000 years ago in northern South America.

Smilodon fatalis skull cast. (A) Side view. (B and C) Frontal views. In (B) and (C), the laterally compressed shape of the tusks can be seen. Courtesy Naturaliter srl www. Naturaliter.com.

Chapter 2.2.2.3 Tribe Homotheriini This tribe is also composed of older genera such as Amphimachairodus which lived from 9.5 to 5.3 Mya with a wide distribution and average size, and more recent genera including Homotherium (18 Mya
10,000 years ago) with many species in Eurasia, Africa, and the Americas; this genus presents a slightly slimmer and lighter structure than Smilodon.

Xenosmilus, one of the largest genera of the subfamily, reached 300
350 kg and was perhaps slightly smaller than S. populator, the largest species of all felids. About 1 Mya they lived in North America. Although they had massive canines, this genus did not have canines as long as those of the Smilodon.

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(A) Skull of Homotherium. (B) A beautiful reconstruction of Homotherium latidens with shorter and more robust canines than Smilodon. (A) Courtesy Naturaliter srl www.Naturaliter.com; (B) courtesy of autor Artem Holubiev.

Chapter 2.2.2.4 Tribe Machairodontini According to some paleontologists M. pseudailuroides of Turkey and China, dating back to about 12.5 Mya, represents the first documented form of Machairodontinae with long teeth that were very flattened laterally.

The genus related to Machairodus had many species (at least six) widespread in Eurasia, Africa, and North America, from 20 Mya to 125,000 years ago. Some species weighed up to 300 kg, with Machairodus horribilis up to about 405 kg (Deng et al., 2016).

(Left) Skull, and (right) reconstruction of Machairodus giganteus from a drawing by Mauricio Anto`n. Courtesy of Mauricio Anto`n.

This graph shows one of the taxonomic hypotheses that classify the genera and tribes of the subfamily Machairodontinae with the fossil skulls of the main species. http://palaeos-blog.blogspot.com/2013/03/notas-cortas-nuevo-dientes-de-sable.html, Modified by Wikipedia (Machairodontinae) 2013.

In this phylogenetic proposal by Wallace and Hulbert, the tribes of the Homoteriini and Metailurini are suppressed and, among the Smilodontini, a new genus and a new species, Rhizosmilodon fiteae, are added. The last fossil of a saber-toothed cat found in Florida dating back to the Early Pliocene, described in 2013. This represents the oldest of the Smilodontini species. Wallace, S.C., Hulbert Jr, R.C., 2013. A New Machairodont from the Palmetto Fauna (Early Pliocene) of Florida, with Comments on the Origin of the Smilodontini (Mammalia, Carnivora, Felidae). PLoS One.

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The Rancho La Brea fossil deposit The most famous paleontological site regarding the fossil record of saber-toothed cats is an osteological site in the plains of Santa Monica in California, which today is surrounded by skyscrapers in a public park in the center of one of the largest cities in the United States—Los Angeles. The area was part of a large estate (Rancho) of 4400 acres. Its last owner was George Allan Hancock, who recognized the scientific importance of the fossils found in the asphaltic deposits. Hancock Park was created in 1924 when he donated 23 acres of the ranch to the County of Los Angeles with the stipulation that the park be preserved and the fossils properly exhibited. It is an area dotted with a series of small lakes in which the hydrocarbons that flow from the subsoil are collected in the form of tar, bitumen, asphalt, and pitch, called tar pits. Its formation dates back to the late “Ice Age” between about 50,000 and 14,000 years ago, which falls within the Wurm glaciation (in Europe) and the corresponding Wisconsin glaciation in North America. The Spanish term “brea,” which means asphalt, defines the area well. In the past the area was frequented by many species (about 500) typical of a North American Pleistocene grassland ecosystem, including especially mammals: proboscideans (Mastodon americanus and Mammuthus columbi), bison (Bison antiquus and Bison priscus), Cervidae, Camelidae, Equidae (Equus

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occidentalis), three species of giant sloth, Canidae (coyote, lupo, and Canis dirus), many specimens of Machairodontinae felids (S. fatalis and Homotherium serum), other felids (Miracynonyx, Panthera onca augusta, P. concolor), including 80 American lion skeletons (Panthera leo atrox). There are also many species of birds, especially birds of prey (golden eagles, hawks, and buzzards) and vultures (a species of Gymnogyps, ancestor of the California condor). These specimens have been trapped in tar pits, by bituminous sands which, given the oily and viscous nature of the hydrocarbons, enveloped the corpses and enabled perfect fossilization. Today’s “La Brea Tar Pits Museum” (ex G. Page Museum), and other American museums, in all, hold 600,000 fossil records from this paleontological site, which is one of the most important and interesting in the world. Predominant among these findings are the remains of S. fatalis, with 200,000 bone fragments (with which it was possible to recreate many complete skeletons), belonging to 4000 specimens. The opening of a new fossiliferous deposit, called Project 23, will engage a large number of researchers for many years and the wealth of finds could double the already huge collection of the museum which now has almost three million fossils.

Photo of the fossil excavation works of Rancho la Brea tar pits in 1909. https://tarpits.org/our-story/ about-the-page

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(A) Smilodon fatalis fossil skeleton. This is the most common species of saber-toothed cats among the fossils of Rancho la Brea Tarpits, where so far about 4000 specimens have been found. https://commons.wikimedia.org/wiki/File:Smilodon_fatalis_UMNH_White_Background.jpg. (B) An artistic and scientific reconstruction of Smilodon fatalis mobbed by a flock of California scrub jay (Aphelocoma californica). The cohabitation of the two species is documented by the fossil findings of this Corvidae in the Rancho la Brea Tarpits deposits. Also, the California poppies (Eschscholzia californica) are among the most common plants that were also present in the bushy prairie habitat, where this species of Machairodontinae lived. Drawing courtesy illustrator Terryl Whitlatch.

Biology of Machairodontinae Very little is known about the social behavior of these carnivores, but some hypotheses have been made based on a comparison with the behavior of extant felids and on studies of fossil skeletons and damage found to bones, caused by diseases or trauma. Some fossil specimens with skeletal damage have been found to have overcome fractures or bone diseases, indicating that these specimens may have been fed, even though they were weakened and unable to hunt for a certain period, until healing occurred. This suggests to some researchers that these animals could feed on prey hunted by other members of their group, and therefore it could be hypothesized that some species of Machairodontinae had a social structure,

perhaps more or less similar to that of today’s lions; to corroborate this hypothesis, it seems that in some species (e.g., Machairodus) there is some evidence of sexual dimorphism between larger males and smaller females, which is not common and not very evident among the current felids, except the lion. The fact that some hunted large or very large prey, makes it possible that they cooperated by hunting in a pack; and finally, facing the difficulties, dangers, and high energy expenditure in taking down very large prey, this is normally only sufficiently rewarding if it will feed more specimens. One finding, not completely explained, highlights a Texas cave where the teeth of Homotherium were found, with 34 specimens of all ages, including very young, along with hundreds of mammoth remains. The fact that so many specimens of Smilodon have been found in Rancho La Brea suggests

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that it was a species that gathered in groups. However, only some authors (Gonyea et al., 2009; Carbone et al., 2008) have considered a social life possible for Machairodontinae, for example, by comparing the percentages of social and nonsocial carnivorous species in

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current ecosystems (steppes and African savannas) that have many similarities with those frequented by Smilodon (North American steppes and savannahs). Others reject the hypothesis of sociality, as it has not been proven sufficiently (McCall et al., 2003).

The coronoid process of the jaw of the Machairodontinae is very different and less developed than that of the current Pantherinae and proportionally less developed, even compared to the smaller species of Felinae. This particular structure reveals that the chewing muscles (temporal and masseter) probably had less space for the attack to stick on the bones and therefore were smaller; this suggests a less energetic bite power compared to current big felids. Courtesy Naturaliter srl www.Naturaliter.com.

Hypotheses and studies have been made in order to discover the function of their typical fangs, which were extremely long in some species, which from a superficial analysis appeared to be cumbersome hypertrophic organs. For many years the only possible hypothesis for their usefulness was that these carnivores fed on a megafauna of large herbivores, composed of some very leathery species, such as pachyderms (elephants and rhinos) and bison. Although this may be true, it did not explain the mechanics of the bite to insert the tusks into the victim’s body. Prof. Per Christiansen (2007, 2011) has published remarkable studies on the dynamics of the bite of Machairodontinae, comparing it with that of current felids, which however have a different mandibular bone conformation and probably a very different musculature, both from anatomical and physiological points of view. Furthermore, not all agree that these felidae knocked down only very large prey while it is thought that, within the subfamily, there were various evolutionary lines regarding the size of the canines and the size of the predated species; for example, Deng et al. (2016)

hypothesize that M. horribilis, despite its enormous size, did not feed on large prey and had proportionally smaller canines than other species. Studying from a mechanical point of view, the skeleton of the neck and the skull and the use of these formidable weapons in some genera, such as Smilodon, interesting discoveries have been made. It has been shown that their mandible (lower jaw) was quite weak, and, compared to current felids (Pantherinae and Felinae), it had a coronoid process (the vertical part that fits into the zygomatic arch) that was much smaller, even if they had huge zygomatic arches; for this the chewing muscles were smaller and allowed a power of bite perhaps not so energetic as that of the big modern Panterini (tiger, lion), but instead the force of the jaws holding the prey by the neck and generally causing its death by suffocation. In addition, the jaw of the saber-toothed cats had a particular anatomy and was connected to the jaw with muscles and tendons that allowed them to open the mouth up to an angular width, between the upper jaw line and the mandible line, above 90 degrees, possibly up to 120 degrees.

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(A) Extant felids: about 65
67 degrees. This Neofelis reaches its maximum at 87 degrees. Courtesy of Naturaliter srl www.Naturaliter.com (B) Machairodontinae (Smilodon) reaches its maximum at about 120 degrees. (B) https://en.wikipedia.org/wiki/File:Smilodon_fatalis_at_maximum_gape_128_degrees.jpg https://www.flickr.com/photos/68214226@N00/52379819/in/photolist-5CsGk (A) The current felid species have an opening angle between the lower and upper jaw, which does not exceed 65
67 degrees. (B) The extinct saber-toothed felines could exceed 90 degrees and often reached 120 degrees; this was an indispensable adaptation due to the enormous development in some species of the superior canines; note also how the coronoid process, which is inserted under the zygomatic arch, is much less developed. This means that the masseter muscle was less developed.

When the lower jaw is closed, it fits perfectly into the upper jaw

At a 65
67 degrees angle of opening, equivalent to the maximum of a current cat such as the lion, the lower jaw of a sabertoothed cat barely exposes the long canines

The saber-toothed feline mouth opening was a huge width compared to modern felids in which this angle is normally 65
67 degrees (today only the nebulous leopards that have very long canines, and can open their jaws at an angle of 87 degrees). At this point it was theorized that species like S. fatalis with its jaws wide open, using ambush and under the impact of a powerful leap, could inflict mortal wounds using their canines

At 120 degrees the lower jaw opens sufficiently to allow the tusks to be used as daggers

like daggers. However, this would have been very dangerous and the fragility of so long and in some cases very thin canines, could have had disastrous results. Only with calculations derived from the anatomical data and using the laws of physical mechanics, can computerized models be created to explain the use of organs such as the extremely strong muscles and the large vertebrae of the neck, the joints of the skull and jaw, and the shape and

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length of the upper canines. We have also attempted to understand the usefulness of the strange anatomical conformation of saber-toothed cats, which often had a particular anatomy, characterized by a powerful front body trunk, with extremely robust and muscular necks and limbs. Using computer models obtained using measurements made on fossil skeletons, the researchers (M. Anto`n, P. Christiansen, etc.) have perfected continuous hypotheses to explain the particular anatomical structure of Machairodontinae and how they were able to use it. One of these particularly credible theories (Brown, 2014), studied the anatomy of S. fatalis, and is based on the strength of the forelimbs, cervical vertebrae, neck muscles, and the use of levers using physical mechanics to explain how the Smilodon species used their canines in the most

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rational way, which was less dangerous for themselves and more deadly for their large prey. It was therefore theorized that their front legs were so large and powerful that they allowed the saber-toothed species to use them in a socalled “bulldogging” move, often put in place by cowboys, in which the neck of cattle is twisted, making them fall to the ground and immobilizing them, for branding. Only after the Smilodon have succeeded in making their prey fall, they use their neck an their long tusks to pierce its throat (see figure C and D (Buldogging and strike) and the drawing of Mauricio Anto`n). The new theory presented by J.G. Brown has resulted from studies into the anatomy of the neck and skull according to the laws of physical mechanics.

Courtesy Brown, J.G., 2014. Jaw function in Smilodon fatalis: a reevaluation of the canine shear-bite and a proposal for a new forelimb-powered Class 1 Lever Model. PLoS One 9 (10).

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This is a recent new theory about how saber-toothed felines (Smilodon) killed their huge prey, which often had a very leathery skin like that of pachyderms (though probably not adults), using their very long fanged upper canines without running the risk of breaking them. The theories exposed up to now have proposed that the impact obtained with an assault on prey while running would ensure that the canines penetrated the tenacious skin of large prey. The danger in this case was due to the linear force that developed with the jump, and the canines being of curved shape and not very robust, could break up due to the impact against the moving prey. Instead, according to this theory based on the mechanical principle of levers, they could enhance the impact of the teeth hence avoiding the risk of breaking them

Courtesy J.G. Brown.

because with bulldogging move the prey was landed and immobilized. (A) Bulldogging. Through the muscles of the enormous front legs the neck of prey was twisted, making it fall. When the prey had landed and panicked, the stout neck, the open lower jaw, and the skull with the unlined canines came into play, all used as a class 1 lever (levers whose fulcrum is located between the point of application of force and the point of resistance). (B) Strike. By simply rising onto its strong front legs, the neck also rose up and curved above the head and Smilodon then applied great strength with this type of natural lever; rising, the neck rotated the skull around the lower jaw and the temporomandibular joint (TMJ) which, resting and fixed to the neck of the prey, served as the fulcrum of the lever.

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The drawing above (A, B, C, D) and the sequence of Mauricio Anto`n’s drawing (1, 2, 3) illustrate well the steps of the capture of a large prey by a Smilodon: first the knockdown with the force of the forelegs and then the fatal bite with the tusks that cut the trachea and the blood vessels of the throat, to kill it. Courtesy Mauricio Anto`n.

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Smilodon fatalis lived from North America to Northwest South America. Smilodon populator lived only in South America. Smilodon gracilis lived in North America but has been found in Venezuela together with a new species of saber-toothed cat, Homotherium venezuelensis (Rincon et al., 2011).

Chapter 2.2.3 The current Felides

(A) Subfamily Pantherinae: Amur leopard (Panthera pardus orientalis). (B) Subfamily Felinae: Ocelot (Leopardus pardalis).

Within the last two felid subfamilies, Pantherinae and Felinae belong both extinct forms, such as the cave and American lions, and also 41 species that are currently known. They are also called conical-toothed cats because their canines have a rounded section, which is not as elliptical or flattened laterally as in many saber-toothed cats, and in

contrast to these, they present well-developed lower canines. Other typical anatomical features (muscles, skeleton, fur, etc.) that characterize the current felids are analyzed in the following paragraph (y2.3). There are few fossil records of these two subfamilies (compared to Machairodontinae), probably for several reasons not least

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because almost all species, especially of Felinae, live and lived in environments not very suitable to the formation of fossils, such as various types of wet forests (Werdelin et al., 2010). For this reason, in the phylogeny of these taxa there are long branches (ghost lineages) of some thousands of years, calculated from studies of molecular phylogeny but totally devoid of paleontological evidence. The current felids are subdivided into eight phylogenetic lines or lineages.

The Pantherinae subfamily belongs to the lineage Panthera with five species of the genus Panthera: lion, tiger, leopard, jaguar, and snow leopard, and two species of the genus Neofelis: Indochinese clouded leopard and Sunda clouded leopard. All species of the genus Panthera have nonossified hyoid bone, while Neofelis has the hyoid bone variously ossified as in all Felinae. To the subfamily Felinae belong the other seven lineages, with 12 genera and 34 species.

Chapter 2.2.3.1 Subfamily Pantherinae and lineage Panthera

leopard. The oldest fossil belonging to current leopards was found in Africa and dates back to 2 Mya, while in Eurasia there is a fossil from 1 Mya. The oldest lion is from Africa and dates back only 1.4
1.2 Mya (Hemmer, 2011). All the other fossils of Pantherinae so far discovered date back to the more recent periods of the Pliocene and the Pleistocene, between 2.6 Mya and 11,000
10,000 years ago. There are two species known to be from China: the socalled Longdan tiger (Panthera zdanskyi; Mazak et al., 2010) of the Early Pleistocene (about 2.55
2.16 million years ago) and another Chinese species (Panthera palaeosinensis; Zdansky, 1924) of more or less the same age; both, although called paleo-tigers, are ancestral forms of the phyletic line that only much later led to the current tiger (1.5 Mya), so that Mazak (2010) considers P. palaeosinensis more similar to the lion or leopard, considering the fossil evidence of the Central Asian origins of the Pantherinae. A Eurasian jaguar Panthera (onca?) gombaszoegensis 5 P. toscana dates back to about 1.5
0.9 Mya with Eurasian fossils which also confirm the same place of origin of a species of jaguar, which today is widespread only in Central and South America. The fossils of European cave lions, Panthera (leo?) spelaea and North American lions P. (leo?) atrox date back only 300,000
400,000 years ago and are widely documented

Lineage Panthera includes two genera and seven species, five large (Panthera) and two medium (Neofelis), spread in various environments, from high mountains, to savannahs, to the rainforests of Africa, Asia, and Central and South America. In historical times, the Caspian tiger also lived in Europe. The success of the feline anatomical model has not required major evolutionary changes since about 10.8 Mya, according to O’Brian and Johnson (2007), when the ancestors of the Pantherinae appeared, up to the present day. This dating is, however, largely based only on hypotheses of genetic origin and on DNA studies which also reveal that between 6 and 6.4 Mya, the genera Panthera and Neofelis separated into two distinct phyletic lines. However, we have very few fossils of extinct forms that can accurately confirm this chronology. These are therefore “ghost lineages” that are not supported by dating of fossil finds of ancient Pantherinae. The oldest fossil of Pantherinae, known since 1987, dates back only to 3.8
3.4 Mya and belongs to the lion-leopard (Panthera sp.?) of Laetoli (Tanzania), perhaps a still indistinct shape of Panthera that only later could have differentiated itself into the current species of lion and

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in many paleontological sites, but they do not confirm anything about the ancient origin of the Pantherinae. The few remains attributable to the snow leopard (Panthera uncia) are very recent and uncertain and there are no fossil remains of the genus Neofelis. A discovery of the oldest fossil of Pantherinae, dating from 5.9 to 4.5 Mya, was made in 2010 on a plateau of Tibet and is called P. blytheae. This is the only one fossil record that confirms the Miocene origin of the subfamily but also its Central Asian origin, questioned by the fossil of Laetoli found in Africa. According to the discoverers of the fossil, this dating would take the dating proposed by O’Brien and Johnson on the lineage Panthera a few thousand years back.

Chapter 2.2.3.2 The occurrences of Panthera blytheae and Its importance in chronological dating of Pantherinae On the pages of the Royal Society magazine, Proceedings B, a new fossil species was described in 2013 that could fill the knowledge gaps concerning the origin of big cats. The team of American-Chinese scientists who studied the fossil at the Natural History Museum in Los Angeles named the new species P. blytheae, in honor of Blythe

Haaga, daughter of Paul and Heather Haaga, entrepreneurs and great benefactors of the Natural History Museum for many years. The fossil was found on the Tibetan plateau in 2010 and dates back to a period between 4.05 and 5.95 Mya, between the late Miocene and the Lower Pliocene. It is therefore the most ancient panther species ever found. Until that point, the primacy of the most ancient fossils belonged to African ones, and particularly to those of Laetoli, in Tanzania, ascribable to Panthera sp. and dating back up to 3.6 Mya, and so much more recent than P. blytheae. This new species is similar to the snow leopard (P. uncia) but has intermediate characteristics that place it on the evolutionary line of other species of big felids. The discovery of the fossil of P. blytheae proves the following points: 1. The separation of the Pantherinae in the current genus Panthera and Neofelis at about 16.4 Mya, occurred much earlier than previously thought, that is, about 6.4 Mya; 2. Central Asia is the region of origin of the Felides; 3. The geological raising of the Tibetan plateau and the consequent geographical, geological, and ecological variations of Central Asia, have had a great importance in the diversification of the various Pantherinae species.

On the left: A three-dimensional reconstruction with the skull bones (nasal, maxillary, premaxillary, jugal, squamous, etc.) and the teeth (upper canines and premolars) indicated in different colors. On the right: The fossil skull of Panthera blytheae found in Zanda on the Tibetan Plateau in Central Asia. Holotype cranium of P. blytheae, IVPP V18788.1. (A) Three-dimensional reconstruction of cranium, dorsal view. (B) Cranium dorsal view. (C) Three-dimensional reconstruction of cranium, left lateral view. (D) Cranium left lateral view. (E) Three-dimensional reconstruction of cranium, ventral view. (F) Cranium ventral view. f.s., frontal sinus; mx., maxilla; pmx., premaxilla; n., nasal; i.f., infraorbital foramen; j., jugal; sq., squamosal; C, upper canine; P3, upper third premolar; P4, upper fourth premolar (carnassial), P2.a, alveolus of upper second premolar. By Tseng, Wang, Slater, Takeuchi, Li, Liu, Xie, 2014. Himalayan fossils of the oldest known pantherine establish ancient origin of big cats. Proc. B R. Soc. https://royalsocietypublishing.org/doi/full/10.1098/rspb.2013.2686

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Mauricio Anto`n: artistic-scientific reconstruction of Panthera blytheae starting from a three-dimensional view of the skull. By Tseng, Wang, Slater, Takeuchi, Li, Liu, Xie, 2014. Himalayan fossils of the oldest known pantherine establish ancient origin of big cats. Proc. B R. Soc. Courtesy Mauricio Anto`n.

Map from Tseng, Wang, Slater, Takeuchi, Li, Liu, Xie, 2014. Himalayan fossils of the oldest known pantherine establish ancient origin of big cats. Proc. B R. Soc. https://royalsocietypublishing.org/doi/full/10.1098/rspb.2013.2686.

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The importance of the discovery of P. blytheae is manifold: first, it changes the temporal estimates on the origin of big cats, realized through molecular biology procedures and with only the fossil record of Laetoli, the origin dated around 10.8 Mya instead of 16 Mya, thus filling an important gap in time. Second, the fossil indicates that the origin of these animals is located in Central Asia, as predicted by different biogeographic models, rather than in Africa, as suggested by the Tanzanian fossil of Laetoli. It is no coincidence that all species of Panterini, with the exception of the jaguar (which still has an ancient

Eurasian origin in P. gombaszoegensis and which does not appear on the map), are exclusively Eurasian (Siberian and Caspian tiger) or Asian (royal and Sumatran tiger, snow leopard, and clouded leopards) or have an area between Asia and Africa (leopard, African and Indian lions). The upward map shows the distribution of the current species and the fossil discovery sites of some extinct species; following the arrows one sees that from Central Asia the various species of large cats have irradiated into almost all the continents; the star indicates the location of the discovery of P. blytheae.

The colors of the nodes indicate the zoogeographic distribution of the species, while the length of the dark bars (blue) indicates a credible interval of possible probabilities, between the minimum and maximum dating, of the considered event [highest posterior density interval]. If the event is more recent the interval is shorter (see diversification between Panthera atrox and spelaea) but it progressively lengthens if the event considered becomes more ancient (see diversification between Panthera and Neofelis). The black bars indicate the dating of fossil species. Modern and historical geographical ranges and fossil localities are indicated for terminal nodes, these have the same colors as in the previous map. By Tseng, Wang, Slater, Takeuchi, Li, Liu, Xie, 2014. Himalayan fossils of the oldest known pantherine establish ancient origin of big cats. Proc. B R. Soc. https://royalsocietypublishing.org/doi/full/10.1098/rspb.2013.2686.

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Comparison between precedents and new hypotheses on the dating in the evolution of the Pantherinae. Clade

Dating hypothesis average (minimum and maximum) after Panthera blytheae (Mya)

Dating hypothesis minimum and maximum, before P. blytheae (Mya)

Diversification between Panthera
Neofelis

16.40 (B8.37
27.68)

6.4/10.8

Start of speciation of the genus Panthera

10.72 (B5.57
19.33)

3.92/6.27

Diversification between P. tigris
uncia
blytheae

8.78 (B4.86
15.13)




Diversification between P. uncia
blytheae

6.97 (B4.23
11.69)




Diversification between P. onca
pardus
leo
atrox
spelaea

7.74 (B3.34
14.79)

2.87/4.27

Diversification between P. pardus
leo
atrox
spelaea

6.00 (B2.73
11.70)

1.70/3.15

Diversification between P. leo
atrox
spelaea

4.01 (B1.48
8.04)

1.9/2.4

Diversification between P. atrox
spelaea

2.87 (B0.69
5.76)

B 1.00

Modified and simplified by Tseng, Wang, Slater, Takeuchi, Li, Liu, Xie, 2014. Himalayan fossils of the oldest known pantherine establish ancient origin of big cats. Proc. B R. Soc. https://royalsocietypublishing.org/doi/full/10.1098/rspb.2013.2686

The discovery of P. blytheae provides new important information because of its anatomical characteristics, which place it as an ancient species closely related to the snow leopard. Based on the finding date, a new chronology of the Panterinae phylogeny was proposed using various methodologies based on calculation of the Bayesian statistics and applying highest posterior density (HPD) interval. Thus credible intervals could be obtained from which to hypothesize a probable date.

The above table compares the dates of the various events that took place in the evolutionary history of the Pantherinae, with the times proposed before and after the discovery of the Tibetan fossil. It begins with the dating of the separation (diversification) that occurred between the evolutionary line that gave rise to the genus Neofelis and to the one that originated the genus Panthera; today it is thought to have occurred at about 16.4 Mya with an HPD interval between 8.37 and 27.68 Mya, much earlier than previously assumed.

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Chapter 2.2.4 Subfamily Felinae

Family Felidae Chapter | 2

The subfamily Felinae includes all the species of small and medium-sized wild cats, which cannot roar because they have a completely ossified hyoid bone, including the puma and the cheetah, despite these two species being larger than the others, with dimensions similar to those of the Pantherinae, to which they were ascribed for many years. Apart from the dimensions, the anatomy of the Felinae does not differ much from that of the Pantherinae, and there is also a strong similarity between the various species of the subfamily itself, so that is not easy to distinguish their skulls and skeletons, attributing them to their respective species, let alone discovering whether a fossil find belongs to a certain taxa (genus or species) hitherto unknown or to already determined fossil findings.

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The classification of fossils is quite problematic. Ancient remnants of Felinae, such as Pristifelis attica (Anto`n et al. 2012), were classified as Felis attica and only after extensive analysis did they understand the phylogenetic distance from the genus Felis, considering it instead an ancestor of many other Felinae; another case refers to a fossil classified as an ancestor of the lynxes, Lynx issiodorensis, which in 2003 was attributed instead by Morales et al., to the caracal lineage and named Caracal issiodorensis—a hypothesis challenged by many researchers. In 2018 some Italian paleontologists (Cherin, Iurino, Sardella, et al. 2018) studied fossils of felids partially included in the original rocky matrix, using “propagation X-ray phasecontrast synchrotron microtomography” technology.

As can be seen from the drawing, apart from a reduction in the number of teeth, the anatomical model of the felids has not undergone dramatic evolutionary changes since about ten million years ago. This is why it is not easy to recognize the skulls of current species and especially fossil species. (A) Skull of Proailurus lemanensis; (B) skull of Neofelis nebulosi. Modified by B. Van Valkenburg, B. 2007. De´ja`vu: the evolution of feeding morphologies in the Carnivora. Integr. Comp. Biol. 47 (1) 147
163.

They thus had the opportunity to obtain perfect 3D reconstructions of the fossil remains (skull remains) and were able to classify them as belonging to the same species as the giant cheetah (Acinonyx pardinensis) of the Plio-Pleistocene of Eurasia and North Africa. The large size and some characteristics similar to the Panterinae, resulted in classification of many of the fossils of this species as Eurasian jaguar or P. (onca?) gombaszoegensis. Sometimes one can only identify a species knowing very well the arrangement of the bones of the skull and the various “foramen” of the base of the skull, but in fossils these characteristics do not always appear very clearly. To this is added the partiality of the findings that may consist of some teeth, and also the rarity of fossil findings, especially with regard to the many species that lived in habitats unsuitable for fossilization of organic remains (e.g., equatorial and tropical forests). These difficulties hinder clarification of the phylogenetic and/or phylogeographical origin of the seven Felinae lineages, therefore much of what was

hypothesized is largely based on molecular biology studies or on the possibility of finding traces of ancient DNA in fossils. Unfortunately, the various methods and data used for genetic research leave ample opportunity for new phylogenetic and chronological hypotheses that for now do not seem to coincide perfectly (see above in Classification) but that are probably increasingly closer to the reality of what actually happened in the evolutionary history of the Felinae.

Felinae Lineages As we have already described, there are controversies about the actual chronological sequence of the evolution of the various Lineages; the sequence adopted here takes up that of O’Brian and Johson (2006) and wants to be only a list of all the lineages. We do not know for sure how this list is accepted from a chronological point of view, as it is questioned by new investigations and research in the genetic field, carried out in recent years.

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Bay cat lineage This includes three species of cats of small or medium size, typical of the forests of South East Asia. The two closest species (Bornean bay cat and Temmink’s cat) belong to the genus Catopuma, while the marbled cat, with an older phylogenetic origin, is separated into the genus Pardofelis. There is no fossil record of the Borneo bay cat’s lineage and the phylogenetic hypotheses are based on data obtained from molecular biology studies. According to O’Brien et al. (2006) this, among the Felinae, is the most ancient of the lineage, having already appeared 9.4 Mya. However, according to Li et al. (2017) the oldest lineage is that of the caracal. According to these authors, lineage lynx and bay cat have a common origin and share their ancestors from about 8.5 up to 7.5 Mya when they separated definitively by dividing into the two existing lineages.

Caracal lineage There are three species of these medium-sized cats typical of forests and semiarid areas of Africa and the Middle East. Two related species belonging to the genus Caracal and one species, the serval, to the genus Leptailurus. This lineage started its evolution in Africa (and perhaps in southern Europe) starting from more than 10 Mya (Li et al., 2017). African fossils of a species similar to the serval of 3.8 Mya and fossils of C. issiodorensis and Caracal depereti (Morales et al., 2003) of Africa and southern Europe have been reported (but are not by all accepted as such).

Ocelot lineage There are eight or nine species of these small and medium-sized cats, some very similar to each other, and typical of Central and South America. They all have 36 chromosomes instead of 38. According to molecular biology analyses, the ocelot lineage evolved in North America from unknown ancestors from about 8 Mya. All the rare fossils of this lineage are recent and date back to 0.78/0.5 Mya as the enigmatic Felis (?) vorhouensis of the Pampean in Argentina. The Panamanian bridge began to join North and South America about 3
2.8 Mya (O’Dea et al., 2016) but the climatic changes continued with a consequent rise and fall of the sea level making it useable or not for alternating periods, until its complete stable formation occurred towards the middle Pleistocene. Thus the species of ancestor cats of this lineage, in successive waves (at least five or six) from North and Central America, reached South America in the periods when the bridge was accessible, under the influence of

climatic and ecological variations. It is therefore in South America, starting from about 3 Mya, that the genus Leopardus, through probable mutations, adaptations to the various environments, immigration of new species of cats, and interbreeding between related species (still in progress) would have diversified into the current eight or nine species.

Lynx lineage There are four medium-sized species all very similar anatomically, typical of the temperate or cold zones of Eurasia and North America all belonging to the genus Lynx. They have long legs compared to their body size, ears with black elongated ear tufts (like the caracal), variously spotted coat, and a very short tail that is only a few centimeters long. All have only 28 teeth and have the socalled “fedine” or whiskers of long hairs that frame the head. Fossil remains have been discovered, especially in Europe (L. issiodorensis) from the Pliocene
Pleistocene from 5/4 Mya to 500,000 years ago. According to Li et al. the lynx lineage shares common ancestors with the bay cat lineage.

Puma lineage This includes three very different species, from small size (from 3 to 10 kg in the jagouaroudi) up to 80 kg for the big pumas of the northern regions of North America. They live in the forests, savannahs, and mountains of North and South America and (cheetah) Africa and the Middle East. There are interesting fossil remains of the lineage Puma, from which also derive the cheetah and the jaguarundi, and which originated about 6.7 Mya in Eurasia. The group that gave rise to the Puma is very close to the fossil Puma (Viretailurus) pardoides from the end of the Pliocene and the beginning of the Pleistocene of Eurasia. This group migrated to North America where, 4.9 Mya, the also gave rise to two species of puma fossil Miracinonyx (with the appearance of feline runners, similar to cheetahs) and finally arrived in South America where the current jaguarundi and puma originated. While the ancestors of the pumas migrated to South America, the ancestors of the cheetahs, such as the enormous Acinonyx pardinensis, which remained in Eurasia, gave rise to other forms of cheetah, including the current one, and even reached Africa. The current P. concolor only recently began to (re)colonize much of North America, where it was extinct during the great extinction of the Pleistocene megafauna.

Family Felidae Chapter | 2

Asian leopard cat lineage There are five species of the genus Prionailurus which are small or medium-sized: from 2 kg for the rusty spotted cat (perhaps the smallest feline) to the 16 kg of the fishing cat. They live in the forests of India, South East Asia, to southern Russia. One of the species, the Sunda leopard cat (Prionailurus javanensis) an island form from the Philippines to Java, was definitively genetically recognized and split only in 2017 (Patel et al. 2017) from the Bengal leopard cat (P. bengalensis). The sixth species, the manul (Otocolobus manul) of the cold Central Asian steppes, is not always associated with this lineage, but with that of the domestic cat. There are no ancient and complete fossils that can confirm the lineage phylogeny, with paleontological evidence and findings.

Domestic cat or Felis lineage This lineage includes six small species (with a maximum weight of 13 kg in the jungle cat), plus domestic species, all belonging to the Felis genus, distributed in Eurasia and Africa in various environments, from northern forests, temperate or dry tropical, to savannahs, and from steppes to deserts. All the phylogenetic hypotheses agree that after the separation from the common ancestors with the Bengal leopard cat lineage, which occurred about 7
6.7 Mya, the domestic cat lineage (Felis), according to hypotheses based on molecular analysis, would have started its diversification in the various species, between 4 and 3.4 Mya. It is therefore the most recently evolved lineage. The lineage initially had a Eurasian origin in regions and periods with a temperate climate, and none of these species has then colonized equatorial or rainforests. Dating back from 10/9 to 4 Mya, a series of not welldefined fossils could represent still undifferentiated forms of Felinae, like Pristifelis attica of Eastern Europe which was the size of a wildcat, as well as Felis (?) christoli of Spain and France, but which date back to 7
4 Mya. Both are therefore certainly earlier (more recent) than the beginning of the specific differentiation of the Felis genus, datable to about 3.4 Mya; and we do not know if they are indeed species that “will lead” to the genus Felis or to species of other lineages of Felinae. The only fossils almost certainly comparable to the genus Felis are attributable to the wild cat of Martelli (F. (silvestris?) lunensis Martelli, 1906) which is known in Europe (in Olivola in the Tuscany region of Italy) and could date back to the late Pliocene about 2.5
1.4 Mya (2? Mya) (Kurte´n, 1965; Kitchener, 1991). Fossil remains suggest that the passage from the wildcat of Martelli to the

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modern wildcat may have occurred during the Middle Pleistocene, 450,000 2 350,000 years ago. All in the making, however, are the hypotheses on the history of the domestic cat (Felis catus). According to many authors it is very similar to the African wild cat (Felis libyca), whose fossils are distinguished from those of the European wildcat due to the larger size of the mandibular teeth, a character also shared by the domestic cat.

Chapter 2.3 Anatomical features of current Felids The anatomy of felids is perfect for their lifestyle based on predation: they have developed senses to find prey, especially smell, hearing, and very acute sight that, thanks to the frontal position of their eyes, allowing an indispensable binocular or stereoscopic vision to evaluate distances, and dilatable pupils for night vision. The senses of smell and hearing are very important because, being mostly solitary and territorial felids, the male and the female mark the boundaries of their territories or meet, aided by smell of urine and the glands that emit pheromones. The roar and various meows emitted by felids during the reproductive period are another sign of sexual and territorial communication. Their body is equipped with powerful limbs and paws with hooked, retractable, and extractable nails, a supple and agile body with a robust, but very flexible vertebral column, a toothed skull with zanniform canines and sharp mandibular teeth, with a pair of “feral teeth” able to cut flesh from bones; and the short jaws with very strong muscles are an indispensable weapon for predation. The digestive system presents a short “small intestine” (three to six times the length of the body) and among their digestive enzymes is urate oxidase or uricase, which allows them to digest the uric acid contained in meat. The very limited length of the intestine does not require a capacious belly and allows them to maintain slender and light forms suitable for quick movements and agile, quick sprints in the pursuit of prey. The powerful ribcage contains an efficient heart and lungs, essential in the supply of oxygen to the blood and muscles during the most tiring stages of hunting. These and other characteristics constituted a highly adaptable and valid anatomical model. This model has therefore been handed down from the start of felid evolution (Pantherinae and Felinae), more than 11 Mya, with minimal variations, to the current felids. The model also supports adaptations in the remarkable variability in size and is valid for the predatory habits of the larger species of Pantherinae, tiger, lion, jaguar etc., and equally for those of small cats that, in their most tiny format, have all the predatory

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skills of large carnivores, and are able to develop a proportionally similar force adapted to the size of their prey. With small anatomical variations this “feline” model can therefore be adapted to an extraordinary variety of environments and trophic or ecological niches. There are felids of tropical forests and desert, felids of very cold climates (Canadian lynx, snow leopard), sprinters and pursuers, such as the cheetah, and ambush specialists like the leopard. In the forests we find skilled arboreal hunters (margay, clouded leopards), skilled fishermen like the flat-headed cat that plunges like an otter (the fishing cat, tiger, and jaguar are also excellent swimmers and hunters of aquatic animals); we also find extraordinary and fast jumpers like the caracal and the serval that catch birds in flight. Finally, unique among felids (all of which have more or less solitary habits), the lion has a social behavior and normally lives in orga-

nized prides, whose members can plan and implement winning strategies for their hunts, in which many pride members participate.

Skeleton and muscles The felids have a diet based on meat proteins and, among all the Carnivores, their morphology is highly specialized in predation, and therefore the skeleton and muscular apparatus of felids have evolved with adaptations that allow high speed and extreme agility, associated with great power. The slender but robust limbs support a capacious thorax, a thin belly, and a highly flexible spine. The hind legs which are longer than the front ones have strong bones to which powerful muscles are tied, especially in the thighs, and which allow these animals to accelerate very fast and enable extraordinary jumping skills.

Felidae principal bones nomenclature. https://upload.wikimedia.org/wikipedia/commons/c/cc/Animal_biology_%281938%29_%2818196793515%29.jpg

The skeleton (skeletal system) The skeletal system is divided into two parts: the cranial skeleton that includes the bones of the head and the jaw, which is very important from a systematic point of view, because their arrangement tells the evolutionary history of the species, but also from the point of view of social life, relationships or behavior, as there are bones that

form or protect all sense organs: eye socket, tympanic bullae, nasal bones, palate. and teeth. Moreover, the mandibular bones, their arrangement. and functioning, especially for the Felids, are an indispensable tool for the capture and killing of prey and for feeding on their flesh. The cranial box also has the function of containing the brain. The other, postcranial, part of the skeletal system includes the remainder of the bones of the body and limbs.

(A) The skeleton of a species of small cat. https://commons.wikimedia.org/wiki/File:Cat_skeleton.jpg (B) The skeleton of a tiger. Natural History Museum of Pisa University (Tuscany, Italy). Other than size, small and large felids have similar skeletons. In small felids there is a proportionally larger and rounded skull, and the bones of the limbs are more elongated and thin. The big cats also have a proportionally smaller cranial box and therefore have developed bone crests, one sagittal and one occipital, on the cranial box, to increase the attack surface of the temporal muscles that give power to the bite.

The axial skeleton (of the body) of felids has light but very resistant bones, with joints with strong and elastic ligaments that are suitable for the attack of powerful muscles, a perfect set that allows fast and flexible but very energetic movements. This is especially important for movement of the limbs, allowing felids to accelerate very quickly or to walk easily even when, belly on the ground and legs bent, stealthily approaching the prey, with stalking that can last a long time. The scapula is not connected to the trunk by a bony joint, but by muscles and ligaments—this is also the case for the bones of the forelimbs, as the clavicle is almost absent. The size of the limb bones in felines is a good compromise between the length needed to develop speed in pursuit, speed,

power in the shot or jump, and force for a strong grip of the forelimb, which is necessary to retain the prey. The humerus and the femur, the bones of the upper limb, are very long in almost all mammals; in felidae, however, with the exception of the cheetah and the snow leopard, the length of the bones of the lower limbs, that is, the tibia/fibula and radio/ulna, have a longer length; in addition the bones of the foot (tarsus and metatarsus) are very developed, with all felids being “digitigrades,” meaning they walk on the bones of their toes (phalanges).

The very small (vestigial) clavicle is located before the scapula (3). Przemek Maksim, from Wikimedia Commons Skeleton of a cat. jpg. https://upload. wikimedia.org/wikipedia/commons/thumb/c/c6/Skeleton_diagram_of_a_cat.svg/1280px-Skeleton_diagram_of_a_cat.svg.png

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The legs and retractable claws The legs have digital pads, one for each toe (five anterior and four posterior), one great plantar and one small carpal or pisiform (in the front legs) that does not rest on the ground. The pads are soft with viscoelastic properties, which make the gait light and silent. In some species, such as the Canadian lynx, the legs are large, with broad soles (proportionally more than any other feline), and covered with fur so as not to sink into the snow and protect from the cold, so that the pads are almost invisible. In order not to sink into the very soft sand, the sand cats (Felis margarita)

has broad soles covered with fur. One of the typical characteristics of felids is extractable and retractable nails; there are other carnivores that have retractable or partially retractable nails including some Viverrids (civets, genets, etc.) but none has evolved a mechanism as refined as that of the felids, with a fibrous sheath or fibrous-fleshy case, in which the claws are protected when they are not extracted, always maintaining their sharpness as they are not worn during gait. The imprints of walking felids can be recognized because they only show the shape of the pads and never those of the nails.

The big paws of the Canadian lynx (Lynx canadensis) are essential for walking on the snow without sinking, like snowshoes. The plantar pads are not seen because they are completely covered with fur that isolates them from the frost. The same adaptation is present in the snow shoe hare (Lepus americanus) the typical prey of this lynx. https://upload.wikimedia.org/wikipedia/commons/4/4b/Lynx_canadensis_3zz.jpg; https://upload.wikimedia. org/wikipedia/commons/8/8d/Lynx_Canadensis.jpg

Of the South American puma (Puma concolor) in the muddy ground of the Llanos of Venezuela. Note the plantar pads and, in the front leg (left), the four digital pads, as that of the first toe or thumb (spur or dewclaw) does not touch the ground. The marks of the nails are missing, as they are normally kept retracted inside, and do not touch the ground.

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A lion’s right front leg. You can see the strong bones of the radius and ulna, the bones of the carpus, the metacarpus, and the phalanges with claw nails. The paw is supported only on the four metacarpal bones and on the phalanges, typical of the digitigrade gait. The nails are retracted in the rest position. The first toe or thumb is reduced to a dewclaw and does not touch the ground. This is the typical structure of the front legs of all Felidae. Natural History Museum of Pisa University (Tuscany Italy).

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Plantar pads of a lion

Plantar pads of a large feline https://www.shutterstock.com/it/image-photo/lion-paw-35108965? src5DtkjwNnor0TUg5vOPmu4hQ-1-15

https://commons.wikimedia.org/wiki/File:Cat_claw_mechanism.png

Front paw of a caracal while striking, with enlarged phalanges and extroflexed claws. Note the digital pads, one for each toe, the central plantar, and the carpal or pisiform

Family Felidae Chapter | 2

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which notoriously develop more power, which is why the bite of the felines is one of the deadliest of all carnivores. From the point of view of phylogeny and taxonomic classification, the base of the skull (the lower part which includes the foramen magnum and the entire front to the palate) is very important. In fact, by observing this anatomical region, the arrangement of bones and foramen from where blood vessels and nerve branches enter and exit for blood supply and innervation, it is often possible, even in fossils, to determine the genus and species. In the skull of felids there are some peculiar characteristics: Cheetah right front paw The cheetah has only partially retractable nails, they are completely retractable only in the first months of life. In reality, the mechanism in adults is similar to that of other felids, but the cheetah’s nails, even if they are retracted, protrude equally from the toes. The nail of the first toe (spur or dewclaw) in the front legs, is large and hooked, and is used to hit the back of the prey in the run and knock it over (see Chapter 8: Ecology of Felidae). http://www.yourpetsbestfriend. com/.a/6a00d8341bfe0853ef01310fe5e9ce970c-popup

G

G

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The skull The skull is comprised an upper part that includes the jaw, the nasal bones, the base of the skull, and the braincase; and a movable lower part, or mandible, composed of the dental bone and the coronoid process. Compared to other carnivores, the skull of the felids is very rounded with the facial part, mandible, and jaw all of short length, canines very developed and in a very advanced position, almost in a line with the incisors. The shortness of the dental bone length is also possible thanks to the minimum number of mandibular teeth (premolars and molars). This means that the opening and closing movement of the jaw is based on short-arm levers,

G

G

Large eye orbits, proportionally larger in the smaller species, and in an anterior and nonlateral position, this allows felids to have stereoscopic vision suitable for assessing distances. Well developed tympanic bullae, crossed internally by a septum that divides them into two distinct chambers and originates from two different portions of the tympanic bone: an entotympanic and an ectotympanic. The powerful jaw is inserted in the zygomatic arch through the condylar joint and allows almost only vertical movements and very small lateral movements; the coronoid process of the mandible, high and well developed, allows use of the temporomandibular muscles for movements of opening and closing the jaws. The development of the zygomatic arch, proportionally huge, especially in the larger species (Pantherinae), leaves a lot of internal space for the powerful mandibular muscles fixed to the sides of the braincase. The presence in the larger species of two bone crests: a median sagittal above the braincase and an occipital posterior. These ridges have developed to increase the area of attachment of the powerful mandibular muscles that give great power to the bite.

Side and top views of the skull of a leopard (Panthera pardus), subfamily Pantherinae, where the sagittal and occipital crest are noted, and the braincase is proportionally smaller than in the small cats (length approx. 23 cm). Natural History Museum of University of Pisa (Tuscany, Italy).

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Felines of the World

Side and top views of the skull of a jaguarundi (Herpailurus jagouaroundi), subfamily Felinae, where there is no sagittal and occipital crest and the braincase is proportionally larger than in big cats (length approx. 9 cm). It can also be noted that in the smaller species such as the jaguarundi, the ocular orbits are large and placed more anteriorly than in large cats. Natural History Museum of University of Pisa (Tuscany, Italy).

The large skull of the leopard and all the Pantherini has a relatively small braincase for fixing the large and powerful muscles of the jaw, therefore on the top and back of the braincase, some bony crests have developed (sagittal and occipital crest). These are commonly found

in larger felids and provide increased surface area for attachment of strong temporal muscles that activate the opening and closing of the mandible and make the bite of cats very powerful (see Chapter 8: Ecology of Felidae).

Lateral and top views of the skull of a puma (Puma concolor), subfamily Felinae, where the sagittal and occipital crest are noted. Although not a Pantherino (big cats) the puma is large (80 kg). The skull has a proportionally small braincase, that is not large enough to attach the large temporal muscles. Therefore, this species has evolved a sagittal and occipital crest, like the Pantherinae, for evolutionary convergence due to predation. This means that the crests are an evolutionary conquest, necessary for attachment of maxillary muscles and not a character that is transmitted by phylogenetic relationship; in fact the jaguarundi, which has small dimensions, but which belongs to the same puma lineage, has no crest. Natural History Museum of University of Pisa (Tuscany, Italy).

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http://slideplayer.com/slide/3468817/12/images/7/1. 1 2. 1 4. 1 Cat 1 skull 1 lateral 1 view. 1 3. 1 21. 1 6. 1 20. 1 13. 1 5. 1 7. 1 18. 1 10. 1 9. 1 19. 1 17. 1 14. 1 16.jpg. Modified by https://upload.wikimedia.org/wikipedia/commons/b/b4/Leopardus_geoffroyi_skull_1847.jpg

Dentition of current Felides

The Amur leopard (Panthera pardus orientalis) in an intimidating attitude, showing off his powerful teeth.

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Felids have the lowest number of teeth among all the carnivores (28
30 against 48
50 for the Canidae) with long zanniform canine teeth and large carnassial teeth with cusps or cones, that are very sharp. All Felidae have a set of teeth (dentition) as follows: Incisors 5 Inc. 12/Canines 5 Can. 4/Premolars 5 Pm. 10 (8)/Molars 5 Mol. 4/Total 28-30 In the upper jaw the last tooth is the first molar (M1) and is always very small. The first upper premolar, the most anterior of the three, corresponds to Pm2, as Pm1 has disappeared from the teeth of all felids. Pm2 is always very small and is missing in many species that therefore have only 28 teeth instead of 30. Specimens within the species may have different numbers of teeth, with or without Pm2, perhaps because some are lost in youth.

G

The function of the teeth

G

In cats, each type of tooth is adapted to the predation and nutrition of meat:

G

G

G

The different shapes of the various types of teeth illustrate that each one performs a different and very precise function. The canine teeth have a conical shape, called tusks, are used only to kill the prey and are stabbed in the throat, neck, or nape of the prey like daggers; if the prey does not die immediately they are used to maintain the grip until the prey has suffocated. Mandibular teeth (molars and premolars) have sharp and pointed cusps; they are not used in predation and therefore are protected from possible trauma; their function, especially that of the carnassial teeth, which are very sharp, is that of cutting tendons and cutting pieces of leathery skin or detaching pieces of meat, suitable for being swallowed. The carnassial teeth include the fourth upper premolar (Pm4) and the first lower molar (M1). By closing the jaws, the sharp edges of the carnassial teeth function like the blades of a shear. The incisor teeth are used to strip the remnants of meat from bone. There are no teeth suitable for chewing meat which is ingested whole.

Teeth of the upper jaw and mandible or lower jaw of wildcat (Felis silvestris). Pink: canines; blue: carnassial teeth—the fourth upper premolar (Pm4) and first lower molar (M1).

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The carnassial teeth in the skull of jaguar highlighted as blue.

(A) The sharp tips of the maxillary teeth of felids (especially carnassial) are called the cone and style (metacone, paracone, parastyle, and protocone) in the upper teeth; they are called conid (paraconid and protoconid) in the lower teeth. Their sharp-edged tips are a further adaptation to better cut and remove pieces of meat to be ingested. The shape and size of molars and premolars is typical of each species and is often used in taxonomic classification. This is very important in paleontology, when the fossil records of some species are reduced to teeth only. (B)Pieces of meat are detached from the body of the prey with bites with the side of the mouth, where the carnassial teeth first penetrate, and then, when they touch, they work like the blades of a set of shears to detach mouthfuls that are then ingested whole and digested easily and quickly by the gastric juices.

A lion feeding on the remains of a downed gnu. The felid bites the carcass with the side of the mouth as it uses the carnassial teeth to detach pieces of meat.

Courtesy Naturaliter srl https://www.Naturaliter.com

(A) Skull of a serval (Leptailurus serval), where the presence of a small upper premolar which corresponds to the second upper premolar (Pm2) is noted. In some species it is present and in others it may be absent (e.g., Leopardus colocola, according to Barstow and Leslie, 2012). The three species of the puma lineage have all these teeth

(B) Skull of an Indochinese clouded leopard (Neofelis nebulosa) where we note the absence of the second upper premolar (Pm2). In all other Pantherinae species this small tooth is present

Species with only 28 teeth (without Pm2) Lynx lineage (Lynx) is the only lineage to have all species with only 28 teeth: L. lynx, L. pardellus, L. rufus, L. canadensis

Domestic cat lineage (Felis): F. bieti, F. margarita

Asian leopard cat lineage: Prionailurus bengalensis, P. rubiginosus, Otocolobus manul

Bay cat lineage: Pardofelis marmorata, Catopuma temminckii

Caracal lineage (Caracal): C. caracal

Ocelot lineage (Leopardus): L. jacobita, L. colocola (this species has some specimens with and some specimens without the Pm2)

Panthera lineage: Neofelis nebulosa, N. diardi

Family Felidae Chapter | 2

Musculature (muscular system) The muscular apparatus of felids is also designed to develop strength, quick reactions, and acceleration. Their flexible fast-acting muscles make their movements graceful and supple, but are especially suitable for acceleration, jumping and lightning flying, performance over short distances. The cells that make up the muscle fibers are of the rapid contraction type, which need large quantities of oxygen and burn a lot of energy. Felidae muscle is mainly made of these cells, which give power and speed but quickly fatigue the animals. There are also other types of muscle fibers formed by slow-twitching cells that produce contractions that are not fast but are sustainable for a long period of time. These are involved in hunting activities

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during the ambush phase, and allow Felids to move very slowly and furtively, or wait for long periods of time, in an uncomfortable position, with the flattened body to the ground with the paws contracted, but ready to react rapidly. In the musculature of felids, the great development of some muscles is very important: 1. The temporal and chewing muscles, especially the “masseter,” which makes the bite fatal and serves to keep the jaws tightened on the neck during the killing of prey. 2. The powerful shoulder muscles, which hold the forelegs and the scapula to the thorax, and give both great strength and ample mobility to the front legs. 3. The muscles of the thighs that allow rapid acceleration and very high or very long jumps.

https://upload.wikimedia.org/wikipedia/commons/e/ea/Superficial_muscles_of_a_cat.jpg

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Felines of the World

Cheetah with a hunted Thomson’s gazelle. After having chased and killed the prey, felids need time to recover from muscle fatigue. To recuperate from the large amount of oxygen used by the muscles to produce energy, the heart increases the rate of beating and breathing increases in frequency by up to 10 times. A cheetah after the chase goes from 15 to 150 breaths per minute. https://www.shutterstock.com/it/image-photo/cheetah-kill-onmasai-mara-kenya-1242531595?src 5 1rXivLvrWJumdBRN8gEQOw-1-80

All Felidae must remain immobile for a very long time to ambush their prey; for this they have bones and muscles that allow them to remain flattened in the grass, moving imperceptibly little by little toward their prey. https://www.shutterstock.com/it/image-photo/prey-sight-tall-grass-wild-bobcat772117915?src 5 uAdC40GUGzfxHOVo2Qu-og-1-77; https://www.shutterstock.com/it/image-photo/lioness-crouching-grass-guatemala-381926539? src 5 u_FDg6CA7zkTqJvlw6GhXA-1-12

Cats always land on their feet With the help of their excellent sight and balance organ, cats usually find the right position to fall onto their four limbs without getting hurt. This is only possible because felines have skeletons, muscles, and a

sophisticated nervous apparatus that allow them great coordination of movement and agility; they can perform 180 degrees twists thanks to their very flexible spine and can perfectly calibrate muscular efforts even in mid-air.

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Anatomy of the landing technique 1. It is very unlikely that a cat will suddenly fall when it is on a branch or at any high point. However, if this happens small and medium-sized felines know how to put in place an instinctive technique, in order to land on four legs. The steps of this technique are described here.

2. The head of the cat rotates first and, based on information from the eyes and the vestibular apparatus of the inner ear (cochlea, semicircular canals, organ of Corti providing information on balance and movement), the brain prepares the muscles and joints for subsequent movements.

3. Subsequently, the backbone or spine of the cat comes into play. The cat arches and twists the spine so that the front legs and hind legs turn in opposite directions.

4. The legs now play an important role: the cat withdraws the front legs while extending the hind legs, turning the front half of the body faster.

5. As the hind legs turn, the cat withdraws them toward the body, while extending the front legs.

6. This prevents the cat from rotating too much around the head-to-tail axis, blocking itself exactly in the desired position to land. Finally, with all the legs stretched and the back arched, the rotation stops in the position desired by the cat and it lands on all four legs with the force of the impact absorbed by the legs and limbs.

WARNING! These operations require some time and it is not possible for the cat to do it if the fall height is less than half a meter, as it risks falling on its side and hurting itself.

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(A) The safety and the ability to climb, of this clouded leopard, is due to a particularly adapted musculoskeletal structure which allows even in case of fall, to rotate the body so as to be able to land on the four legs. (B) The felines with arboreal habits, such as this Indian leopard (Panthera pardus fusca), despite a size and a weight (50
60 kg) quite relevant, are able to perform real acrobatics by moving among the branches. However the leopard, like the other big species of felids (big cats), is too heavy to perform the landing maneuvers of the small and medium felids. However they can jump from many feet high and land without getting hurt. There is a video documentation (YouTube see Chapter 4.1.2) in which it is possible to see a leopard jumping from the branches of a tree more than twenty meters high; before landing he hits an impala, killing it and then taking it away. https://upload.wikimedia.org/wikipedia/commons/5/50/Clouded_Leopard_Belly_%282%29_NashvilleZoo.jpg?uselang=it; https://upload. wikimedia.org/wikipedia/commons/b/b0/Leopard_davidraju_68.jpg?uselang=it

The fur Felidae fur is one of their most highly regarded esthetic features, however, due to the high monetary value of some furs and because of their rarity, they became a status symbol, and many species were actively hunted to near extinction.

Within the Felidae family there is a great variety of colors and fur patterns, all very beautiful, with each coloring functional to the type of habitat frequented by that particular species.

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The great coat patterns of felines: uniform fur coats (adult lion, adult puma, jaguarundi, caracal), flecks (cheetah, serval, Geoffroy’s cat, lynx, fishing cat), speckled with rosettes (genus Panthera, leopard, jaguar, etc.), large blotched (clouded leopards, marbled cat), small blotched (ocelot, margay, and other South American species), and striped (some species of genus Felis, manul).

These patterns are an adaptation to camouflage the animals in their environment in order to hide or ambush; moreover, Felidae fur has, for many species, a primary protective function from the inclemencies of the climate. It is not clear from which forms (most primitive patterns) derive the various designs and colors of modern felid species, but some hypotheses seem to agree with the latest discoveries in the genetic field, putting in report the design and the phylogeny of the various species (see below “Phylogenetic origin of patterns and colors in feline furs”). The color is also very important from an ecological point of view, as the fur adapts to the climate of the frequented environment. Coats with long and thick “guard hair,” with a very dense “undercoat” (or “down hair”) are used to shelter from cold climates; this kind of coat is found in the Canadian lynx, the snow leopard, the manul, and some other subspecies from cold climates such as the Amur leopard, the Siberian lynx, wildcat etc. Many of these species change the type of fur seasonally, varying the length and density of hairs (number of hairs/cm2) with decreases or increases in temperatures. In some cases there are summer and winter furs that can vary slightly

even in color, with spots that become more or less evident (e.g., the lynx). On the other hand, species in tropical and dry climates often have fur with sparse and short hairs (only guard hair without underfur) including the lion, leopard, caracal, etc. In desert climates, nocturnal species, such as the sand cat, have thick, woolly fur. As for fur color, one of the characteristics of many species of felidae is the variability of coloration with typical phases within the same species. This indicates good genetic variability in the chromosomal set; in fact, these phases or chromatic forms are not due to genetic mutations but to the phenotypic highlighting of genes normally present. Within the same species phases of reddish, blackish, and grayish colorations, more or less densely speckled or unicolor are considered normal. For example, the jaguarundi has a reddish phase (called Eyra) and a dark gray, almost black but grizzled, both of which can be found in the same litter. Reddish and grayish forms coexist in the Bornean bay cat. The serval, the African golden cat, and the Asiatic or Temmink’s cat, have blackish shapes, densely dotted shapes, and spotted phases; sometimes this variability is related to climatic variations and seems to be related to

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the humidity level of the habitat (with dark forms in regions with humid forests). Also melanism, a genetic mutation induced by an error of the genes, which causes the skin to produce an excess of a very dark pigment, called “melanin,” is quite common among felids; for example, in the leopard, the so-called black panthers appear. It is also common in many South American species of the genus Leopardus (L. guigna, L. colocola, L. geoffroyi). Usually melanism, being a mutation randomly arising, is a recessive character, but in the jaguar, where it is very frequent, it is a dominant character. In the cheetah there is a spontaneous mutation called “Rex” that gives

rise to the so-called “king cheetah,” which are born from normal parents but have a striped and grossly spotted mantle; we do not know why, but they are common only in Southwest Africa. Much less common is the mutation of albinism (lack of any type of pigment) that results in a white coat and the irises of the eyes that allow the red of the blood capillary circulation to shine through. So-called white tigers are not albino but specimens in which the yellow-red pigments (pheomelanine) do not develop. They have a whitish coat but they have black stripes that are formed by the presence of brown-black “eumelanine” (see Chapter 10: Genetics).

PHILOGENETICS ORIGIN OF PATTERNS AND COLORS IN FELINE FURS

1- Large blotches fur Typical only of the clouded Leopards and the marbled cat; Phylogenetically it is the most primitive design of all, from this probably, derive all the other types of pattern. Both species that have this pattern, are at the base of their lineage

Clouded leopard

2 -Fur speckled or flecks Typical of cheetah, serval, all lynxes, Geoffroy's cat, Bengal cat, Asian wild cat (Felis lybica ornata) etc. Even the puma has this hair in the first months of life. It is considered one of the oldest and most primitive types of patterns

Cheetah

Puma cub

3 - Rosettes fur Typical of all belonging to the genus Panthera. The tiger also has rosette cloaks, whose stripes are very elongated rosettes; the uniform fur of the lion is a secondary adptation to the colors of the savannah as the young are born with hair with rosettes and keep it for a few months It derives directly from the fur large blotches (Werdelin and Olsson 1997)

Leopard

Immature lion

Tiger

Snow leopard

Jaguar

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4 -Fur with small blotches Typical of many South American species of the genus Leopardus: ocelot, margay. Colocolo, etc.

Ocelot

5- Fur of uniform color Fur of a single color, usually fawn: yaguarundi, caracal, flathead cat, Bornean bay cat This seems to be a derivation of the speckled fur for the cubs of some fawn species, when they are young

Caracal

6 -Striped fur Typical of some species of the genus Felis: Wild cats, cat of the sands and also of the manul It is possibly a derivation of the fur flecks or small blotched pattern

Wild cat

Masai Mara National Reserve Kenya. (Left) Lioness with three young lions showing spotted fur. (Right) Immature lion with spotted fur. The maculation will be lost once they reach adulthood. https://www.shutterstock.com/it/image-photo/young-lion-cub-133699460?src 5 QzYDlf6cmziMDL_ KZFb8IA-1-25

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Furs: patterns, colors, and habitat 1. The is fur almost uniformly fawn—camouflage for the species that hunt in open environments such as grasslands and savannas. They are often spotted in the first

months of life, as happens in young lions and pumas; this may be an ancestral memory (phylogenetic) inherited from their oldest ancestors, which may have had spotted fur.

2. Thickly spotted yellow furs, like that of cheetah, are very useful for hiding in tall grass.

3. The colors with large spots and dark stripes that make the fur very beautiful and precious, such as those of ocelot, leopard, and serval, are very mimetic for the species that hunt using ambush between light and dark and use the light and thick vegetation, especially in tropical forests; these types of patterns are called “disruptive colors,” “disruptive patterning,” or “disruptive camouflage.” The striped fur of the tiger is also part of this category.

Seen with diffused light, the striped colors and large dark spots or faded outlines seem very showy, however in twilight orthehalflightofforests,wherethesuncreateslightanddark by projecting on the ground the shadows of fronds, the big spots of fur “break” the shape of the feline and make it almost invisible.

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The serval is very evident in full light, but in dim light and in the “chiaroscuro” games of the dense vegetation they make it invisible by breaking its outline.

Thanks to the pattern and colors of its fur, the camouflage of this Amur leopard cat (Prionailurus bengalensis euptilurus) is perfect and makes it invisible, hidden in its typical habitat, the mixed forests of conifers and deciduous trees with a cold-temperate climate of South Oriental Russia, Manchuria, and Korea.

Fur as a protection from cold Fur also has a function of thermal insulation and protection from the cold climate of regions inhabited by some northern or mountain species. In regions where the climate is seasonal, in winter, it is important to protect yourself from cold, especially if you have to stay

outdoors for a long time and lie in wait to carry out ambushes. The species of these regions have summer and winter furs. The latter has longer hair (guard hair or giarra) which is much thicker, with a higher density of hairs (number of hairs/cm2) and a woolly undercoat (down hair or borra).

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Eurasian lynx (Lynx lynx lynx) in a snowy habitat. This lynx of the temperate and cold regions of Eurasia, is one of the species in which the fur is used to shelter from the cold and where there is a seasonal variation in the length, density, and color of the hair. Photo by Vincenzo Martegani.

(A) Royal or Bengal tiger (Indian population) https://www.shutterstock.com/it/image-photo/behavior-tiger-316149524?src=veUYYqV2yBeLATJjHeJQXQ-1-80 (B) Tiger (Siberian population). Comparing tigers of different populations we can clearly see the phenotype differences certainly due to different adaptations climatic and environmental conditions. For example, Siberian tigers are more robust with a much longer and thicker coat than Indian, Indochinese and Sunda tigers. (B) Photo by Vincenzo Martegani.

Family Felidae Chapter | 2

Seasonal and geographical variations in the length of hair in tiger furs (Piechocki, 1990). Modified by Macdonald and Loveridge Subspecies and geographic origin

Coat length in summer (mm)

Coat length in winter (mm)

Amur region (Southeast Siberia): Siberian tiger (Panthera tigris altaica)a

15
17

40
60

North China: Chinese tiger (Panthera tigris amoyensis)a

8

30

India: Royal or Bengal tiger (Panthera tigris tigris)

8
15

17
25

a

Indochina: Indochinese tiger (Panthera tigris corbettii)

10
15 b

15
20

Sumatra Island: Sumatran tiger (Panthera tigris sondaica ex sumartae)

10
15

b

Java island: Javan tiger (Panthera tigris sondaica)a Extinct

8
12b

b

Bali Island: Bali Tiger (Panthera tigris balica)a Extinct

7
10b

b

Only the geographical varieties of tiger that live where the climate is seasonal (especially with cold winters) have a winter fur that is different from the summer one. Populations living in warm tropical climates (islands of Sumatra, Java, Bali), do not change fur during the year. a Currently these are no longer considered subspecies but of genetically undetectable geographic varieties. b There are no seasonal variations.

https://upload.wikimedia.org/wikipedia/commons/0/06/ ChausCaudatusWolfSmit.jpg Turkestan wildcat or Bokhara (Felis libyca ornata 5 ex caudata) of Middle Eastern and North African origin, this species does not have a fur particularly suited to cold climates, 3500 hairs/cm2 of density Lithographic printing by Joseph Wolf (1820
1899) from Proceedings of the general meetings for scientific business of the Zoological Society of London Year 1874

The European wildcat, Felis silvestris silvestris, can have 5500
24,000 hairs/cm2 in summer, which increases to 10,000
30,000 hairs/cm2 in winter (Piechocki, 1990). However, Haltenorth (1953) provides much lower values of 1800
4700 hairs/cm2 in summer and 6700
8800 hairs/cm2 in winter (Macdonald and Loveridge)

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Variations in density and length of the guard hair and undercoat in some Felidae species of the Palearctic region (Eurasia, North Africa, and Middle East) Species

Fur density (number of hairs/cm2)

Percentage ratio between underfur and guard hair

Length of the guard hair (giarra) in mm

Length of undercoat (down hair or borra) in mm

Manul or Pallas cat (Otocolobus manul)

9000*

10

69*

40

Eurasian lynx (Lynx lynx lynx)

9000*

12
13

51

31

Caucasus wildcat (Felis silvestris caucasica)

8000

10

44

34

Turkestan wildcat (Felis libyca ornata) (ex caudata)

3500

8

51

35

Snow leopard (Panthera uncia)

4000

8

54*

43

Amur leopard cat (Prionailurus bengalensis euptilurus)

7000

30*

47

34

Turkmenistan caracal (Caracal caracal michaelis 5 schmitzi)

2500

4
5

39

28

Cheetah (Acinonyx jubatus)

2000

35

25

Asiatic cheetah (Acinonyx jubatus venaticus)

There are no definite data on these measurements, but it is known that the Asiatic cheetah, which lives in habitats with cold winters, has a longer and thicker coat than the African cheetah, especially in winter

*Indicates the most significant data.

The Palearctic region includes Eurasia, North Africa (north of the Sahara), and the Middle East; being so vast and with considerable latitudinal variability it includes very cold northern climatic bands, up to the arid warm Middle Eastern deserts and the northern Sahara. Also in this zoogeographic region are mountain ranges and vast high plateaus, such as the Himalayas and Tibet. There are many Palaearctic felids species and, observing the data in

the table, we note that the species that live in cold regions, such as the manul, Eurasian lynx, and snow leopard, have long and thick “guard hair” furs and an undercoat (down hair or borra) composed of long and very dense hairs. Those that live in warm and semidesert regions, such as caracal and cheetah, have short and not very thick “guard hair” (modified by Heptner and Sludskii, 1992). Manul or Pallas cat (Otocolobus manul) in a snowy habitat. This small wildcat has the thickest fur with the longest hairs of all the felines. The length of its hair (69 mm) is greater than that of the snow leopard (54 mm), although this is a big cat (Panthera uncia). https://www.shutterstock.com/it/ image-photo/manul-pallas-cat-wild-livingcentral-255412132?src=OjpvaQ32GzhSMy9MEScTw-1-15.