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Order of carnivores (Carnivora)
Chapter 1
Order of carnivores (Carnivora) Chapter Outline Introduction The carnivorous animals Man and carnivores Chapter 1.1 Anatomical features common to order Carnivora
1 1 2 3
Chapter 1.2 Features of Caniformia and Feliformia Carnivora denture or dentition Chapter 1.3 Evolution, phylogeny, and classification
4 6 7
African lion (Panthera leo leo), order Carnivora, certainly the best known representative of this group of animals, as all members of the family Felidae, is a skilled predator and has a “hypercarnivorous” diet.
Introduction The carnivorous animals Many animals can be defined as “carnivores” from the point of view of their diet: for example, sharks, among the fish, crocodiles and snakes, of current reptiles as well as many dinosaurs from the past; and eagles, hawks, and owls among the birds. Felines of the World. DOI: https://doi.org/10.1016/B978-0-12-816503-4.00001-5 © 2020 Elsevier Inc. All rights reserved.
Many mammals are carnivores, examples include the marsupial carnivores such as the Dasiuridae family or quoll (Dasyurus), the Tasmanian devil (Sarcophilus harrisii), the famous Tasmanian wolf or thylacine (Thylacinus cynocephalus) (relatively recently extinct), and the marsupial lion (Thylacoleo) of the Australian Pleistocene. Other orders of mammals present with totally or mostly carnivorous diets including bats, other insectivores, and some monkeys
1
2
Felines of the World
(chimpanzees, baboons) and prosimians. However, those we will deal with are the carnivores (order Carnivora) that, from a taxonomic point of view, belong to the precise order of mammals and share a common phylogenetic history together with particular anatomical features.
The order of Carnivora includes dogs and wolves, cats and “big cats,” bears, raccoons, weasels, genets, seals, etc.
(A) Eurasian lynx (Lynx lynx linx) order Carnivora, family Felidae. (B) Siberian weasel (Mustela sibirica) order Carnivora, family Mustelidae. (C) Maned wolf (Chrysocyon brachyurus) order Carnivora, family Canidae. This South American species has an omnivorous diet and is particularly greedy for a certain type of wild tomato (Solanum lycocarpum).
Man and carnivores Within the order of Carnivora there are two species of mammals which are the most popular of human pets: the cat and the dog. These are bred everywhere that man has settled; with cats being the most common pet with about 500 million specimens around the world. Dogs, often called “man’s best friend,” is also used as a working animal (for hunting, towing sleds, guarding flocks, etc.) or as guide dogs for the blind, sniffer dogs (police dogs), and for carrying out rescues after avalanches and storms. Their relatives and wild ancestors, namely wolves and the big wild cats, are admired as great hunters, but the relationship with the Carnivora also creates a series of conflicts and a complicated outlook, with opinions that can be very different or even conflicting, in different cultures and in various historical periods. This simple admiration for their strength and beauty has occasionally escalated to a veneration or viewing them as sacred as in many ancient cultural and religious traditions. However, carnivores have also
always been considered as rivals and dangerous competitors, especially when man hunted prey for food; they were and can still be a serious danger to farmers and their livestock, and there is also a conflict over space due to natural and wild environments giving way to agriculture. The invention of hunting as a “sport” as a “test of courage” or to obtain their precious furs, or for other multiple reasons whether selfish, utilitarian, or merely as a convenient petty economy, has reduced many species of carnivores to the point of extinction, especially the larger ones (tiger, lion, bears, wolves, etc.) which need large spaces in which to live together with their prey, with which they play a primary role as predators and/or superpredators, which is an indispensable role in the maintenance of the ecological balance of the natural environment. Many species have been eradicated from most of their natural habitats and relegated to live in restricted protected areas, which are not always sufficient to safeguard their future.
(A) Red tabby (long haired) and (B) Caucasian shepherd dog (a female with four puppies). These are breeds domesticated and bred by man, but which derive from wild carnivores.
Order of carnivores (Carnivora) Chapter | 1
Chapter 1.1 Anatomical features common to order Carnivora The Carnivora are an order of mammals to which belong animals that are almost all adapted to a predominantly carnivorous diet (i.e., they need high percentages of animal proteins obtained from meat and fish meat), and for this reason, their anatomical structure is specialized for predation and in the digestion of this type of food; their “small intestine” is short (three to six times the length of their body) and their digestive enzymes include urate oxidase or uricase, which allows them to digest the uric acid contained in meat. Very few species have subsequently
3
evolved by adapting to an omnivorous diet (composed of different percentages of plant substances and animal substances), such as badgers, bears, and the almost vegetarian, giant and lesser pandas (bamboo eaters), and the aardwolf (Proteles cristata), an Ienidae, and bat-eared fox (Otocyon megalotis), a Canidae, which have an entomophagous or insectivorous diet (termites). Some Canidae, such as the foxes (Vulpes sp.) and the maned wolf (Chrysocyon brachyurus), being opportunistic species, feed abundantly on fruit in the season that they ripen. Felids belong instead to a group described as “hypercarnivorous” as their diet is almost exclusively meat (more than 70%).
The red or lesser panda (Ailurus fulgens) is the only species of the Ailuridae family.
Like the giant panda (family Ursidae), it has an almost vegetarian diet based on bamboo. Both these Asian species, have a sort of “sixth finger” in the front legs, which is the sesamoid bone of the hand, and has the shape and function of an opposable thumb, it is used to grasp bamboo twigs and take them to the mouth. To this order belong minute species weighing as little as 25 g like the least weasel (Mustela nivalis) up to the giant polar bear and Kodiak brown bear, which can exceed 800 kg, although the greatest of all is the enormous southern elephant seal (Mirounga leonina) with a weight of up to 3000 kg. The gait can be plantigrade or digitigrade and the paws are always supplied with strong claw nails. The muscles of the hind legs are often massive, equipped with strong tendons that allow in many cases long leaps and rapid snappy movements (sprinters). In the Pinnipeds (Pinnipedia), earless seals, sea lions (eared seals or otary), and walruses, the limbs are transformed into fins. They have very developed senses, especially sight and hearing, but in some an acute sense of smell prevails as revealed by the development of the nasal mucosa and the olfactory region of the brain, especially in the some
Caniformia and Felidae; the latter also have very acute sight, with eyes suitable for night vision. The following six anatomical features largely define carnivores. 1. All carnivores have elongated and pointed canines with a conical shape called tusks which are used to kill prey; the premolar and molar teeth have a pointed shape with one or more sharp cusps; the so-called carnassial or sectorial teeth are composed of the fourth upper premolar (P4) and the first lower molar (M1), they are larger and very sharp, essential for being able to cut (with a scissor-like action) the muscles and tendons of prey, and to obtain pieces of meat of a size suitable for being ingested. 2. The third upper molar (M3 ) is missing in adult Carnivora dentition. 3. Within the skull it is notable that the braincase (the cerebral portion of the skull) is well rounded and well developed, so that the “frontoparietal suture” of the cranial bones is placed anteriorly. 4. An important characteristic to determine the taxonomic rank in Carnivores is the particular conformation of the bones of the base of the skull; it is here that there is also
4
Felines of the World
the tympanic bulla (auditory bulla), an ovoid hollow bone formation which contains the three hearing bones (the hammer, anvil, and stirrup). Until a few years ago it was believed that the bulla was formed from the tympanic bone only, however, more recent studies have shown instead that its morphogenesis evolved in different ways in the various families of carnivores, and that it may also derive from the fusion of several bones (ectotympanic, rostral, and caudal entotympanics). These different anatomical shapes influence the path of the carotid artery and this set of the features are one of the most important diagnostic factors for the determination of some taxa, including fossil taxa. 5. In the skeleton, the clavicle is missing or very small (vestigial).
6. On the front legs there are always with five digits, often with the first short and vestigial (the dew-claw), which is not used in walking, however, especially in the Felids, it is provided with a hooked claw that is used for predation. There are three small carpal bones (scaphoid, semilunar, and central) that merge into the single bone (“scapholunar”) of the wrist. The hind legs can have four or five digits depending on the gait adopted by the species. Plantigrade species have five digits and digitigrade species four. Felids (cats) and Canidae (dogs and wolves), which include adept cursorial and sprinter species, are digitigrade; meanwhile Ursidi (bears) and Procyonidae (raccoons) which are not cursorials have legs suitable to their plantigrade gait.
(A) In the order of Carnivora the carpal bones (of the front legs), scaphoid and lunar (semilunar), are fused into a single bone, the scapholunar. (B) Within the Carnivora there are various types of gait, plantigrade, semiplantigrade (some Viverridae like Paradoxurus), semidigitigrade (some Mustelidae like the badger), and digitigrade. The digitigrades put only the end phalanges of their digits on the ground, a gait that allows greater speed.
Chapter 1.2 Features of Caniformia and Feliformia The order of Carnivora is composed of 16 families divided into two suborders. 1. The suborder Caniformia, which means “dog-like” includes bears, wolves, raccoons, weasels, etc., and the Clade Pinnipedia. It has evolved with diversification centers that have been found in North America and northern Eurasia; the most ancient fossils found in these continents have anatomical structures adapted to an arboreal life. Today’s representatives of the suborder have largely plantigrade gait, except Canidae which are digitigrade; they tend to have an omnivorous diet and often have a large number of teeth—from 34 (only in
the weasel) to a maximum of 48 50. A diagnostic characteristic is the tympanic bulla, containing a part of the organs of hearing, which is formed by ectotympanic bones and has no internal median septum which divides it into two chambers. In some families including the Canidae and Ursidae, the alisphenoid canal is present and the internal carotid artery is not obstructed by the temporal bone structure and so is not reduced. 2. The suborder Feliformia, which means “cat-like,” includes cats, hyenas, genet, mongooses, Malagasy mongooses, etc. It originated with diversification centers located in Africa and southern Asia, with species with an anatomical structure suitable for an arboreal life. The current species almost all have a
Order of carnivores (Carnivora) Chapter | 1
digitigrade gait (at least in the front legs) and many have nails that are partially retractable or completely retractable, such as the claws of the Felidae. They have a much more carnivorous diet than caniforms and some groups are “hypercarnivorous.” To improve the possibility of predation the most advanced, like some Felidi, has gradually decreased the number of
5
teeth to up to 28 30; in the other Feliformia there can be up to a maximum of 40 teeth. Their tympanic bulla is formed by entotympanic and ectotympanic bones and it is divided into two chambers by a median septum. With the alisphenoid canal absent, the internal carotid artery is reduced because it is obstructed by the bone structure.
Skull of a carnivore showing the basicranial region, where the two auditory or tympanic bullae are seen at the sides of the occipital hole (or foramen magnum).
Feliformia
Caniformia
Section of an auditory bulla of Feliformia Where it is seen that the interior is divided into two parts by a septum
Section of an auditory bulla of Caniformia Where it is seen that the interior is a single chamber, not divided into two parts by a septum
6
Felines of the World
Carnivora denture or dentition Feliformia Few teeth Wild cat (Felis silvestris) skull
Caniformia Many teeth Black-backed jackal (Canis mesomelas) skull
The Feliformia have 28/40 teeth Felidae have 28/30 teeth Hyaenidae have 34 teeth
The Caniformia have 34/48 50 teeth Canidae have 38/42 teeth, but one species has many more
Spotted hyena (Crocuta crocuta). These carnivores have very large teeth and extremely robust jaws to break bones
The Canidae bat-eared fox (Otocyon megalotis) has up to 48/50 teeth, the largest number of teeth among all Carnivora
Viverridae have 32/40 teeth
Ursidae have 40/42 teeth
African civet (Civettictis civetta). The largest of all the Viverridae and the only civet in Africa
Andean or spectacled bear (Tremarctos ornatus). The only South American species of bear
Order of carnivores (Carnivora) Chapter | 1
7
Pink, canine teeth; blue, carnassial teeth (M1) (PM4)
Chapter 1.3 classification
Evolution,
phylogeny,
and
The assumptions made in order to exactly define the period in which the first true Carnivora appeared are sometimes discordant. It had always been asserted that they first appeared in the late Paleocene, but according to the latest fossil discoveries and based on calculations on the evolution of their anatomical characteristics and molecular phylogeny, today it is generally thought that they probably appeared more than 66 million years ago (Mya), at the beginning of Paleocene. It has always been assumed that the fossil forms belonging to the superfamily of Miacoidea were the first true ancestors of modern carnivores. Miacoidea remains are found in Western Europe, Asia, and North America, with some forms that survived for almost the entire Eocene. These evolved into two families: 1. Miacidae with many genera, including Vulpavus, Paroodectes, Miacis, etc. 2. Viverravidae with fewer genera, including Viverravus, Mustelodon, etc. Similar to a cross between small genets and martens, they all presented characteristics typical of arboreal
animals, such as frontal eyes, an elongated skull and body, short legs, long tail, and pointed and retractable claws. Their dentition, typical of carnivores, with long zanniform canines (fang-shaped canines 5 tusk shaped canines) and molars with pointed cusps, was generally composed of 42/44 teeth. However, according to important research in the field of comparative anatomy and paleontology, the true nature of Miacoidea as direct ancestors of the current Carnivora is questioned, with some considering them as only belonging to the Clade of the Carnivoramorpha, which includes the true carnivores, the Miacidae, the Viverravidae, and some forms not well defined from a systematic point of view, including some genera such as Tapocyon and Quercygale (which some authors continue to ascribe to the Miacoidea). Especially Tapocyon, for some of the characteristics of the base of the skull, can perhaps be considered very similar or closely related to the group that originated the true Carnivora. It is, however, quite certain that the first true members of the carnivorous order appeared in Central Asia (perhaps in China) at high latitudes, in regions with a cold temperate climate (Rolland et al., 2015) and there they diversified considerably and then spread to tropical regions later.
8
Felines of the World
Shortly after their appearance (after the middle of the Paleocene) the order was immediately differentiated into the two great present suborders: Feliformia and Caniformia. The results of the latest research indicate that the division between Feliformia and Caniformia began between the beginning and the middle of the Paleocene (57 Mya), whereas before it was assumed to be a much later subdivision, in the middle Eocene about 43 Mya.
Later these Taxa gave rise, in addition to the current families of carnivores, also to many important fossil groups (Nimravidae, Amphicyonidae, Percrocutidae, etc.), which are well represented in many fossiliferous sites and were therefore widely diffused in the past, but which became extinct in various successive epochs but allowing some to survive until the beginning of the Pliocene.
Order of carnivores (Carnivora) Chapter | 1
9
Miacidae: Paroodectes feisti, which belongs to the “Carnivoramorpha” group. These are animals more or less the size of a genet and with arboreal habits. To this group, that dates back to the Pleistocene, there are many genera and species, some of which represent the true ancestors of the modern carnivores.
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Felines of the World
Blue branches (blue lines), Caniformia, Red branches (red lines), Feliformia Figure from Van Valkenburgh, B., Wayne, R.K., 2010. Carnivores. Curr. Biol. 20(23), 2157. Figure created by G. Slater and J. Pollinger. Van Valkenburgh, B. Pang, B., Bird, D., Curtis, A., Yee, K., Wysocki, C., Craven, B. A., 2014. Respiratory and olfactory turbinals in feliform and caniform carnivorans: the influence of snout length. Anat. Rec. 297, 2065 2079. https:// www.researchgate.net/publication/266857277.
Order of carnivores (Carnivora) Chapter | 1
https://upload.wikimedia.org/wikipedia/commons/c/c3/Carnivora_phylogeny_%28eng%29.png
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Felines of the World
After a long evolutionary history, Caniformia and Feliformia have evolved into the current 16 families composed of about 286 species. These are widespread in almost all the natural and anthropized environments of the Earth, from the Arctic tundra to the tropical forests, in deserts, wetlands, and the sea. The carnivores have reached and colonized all the continents except Australia,
but even here they are still present, with at least one species of feral dog, the dingo, imported in prehistoric times (3000 4000 years ago) from Indochina and the Sunda islands by man, but that has now assumed a well-defined ecological role in some Australian ecosystems.
Order of carnivores (Carnivora) Chapter Outline Introduction The carnivorous animals Man and carnivores Chapter 1.1 Anatomical features common to order Carnivora
1 1 2 3
Chapter 1.2 Features of Caniformia and Feliformia Carnivora denture or dentition Chapter 1.3 Evolution, phylogeny, and classification
4 6 7
African lion (Panthera leo leo), order Carnivora, certainly the best known representative of this group of animals, as all members of the family Felidae, is a skilled predator and has a “hypercarnivorous” diet.
Introduction The carnivorous animals Many animals can be defined as “carnivores” from the point of view of their diet: for example, sharks, among the fish, crocodiles and snakes, of current reptiles as well as many dinosaurs from the past; and eagles, hawks, and owls among the birds. Felines of the World. DOI: https://doi.org/10.1016/B978-0-12-816503-4.00001-5 © 2020 Elsevier Inc. All rights reserved.
Many mammals are carnivores, examples include the marsupial carnivores such as the Dasiuridae family or quoll (Dasyurus), the Tasmanian devil (Sarcophilus harrisii), the famous Tasmanian wolf or thylacine (Thylacinus cynocephalus) (relatively recently extinct), and the marsupial lion (Thylacoleo) of the Australian Pleistocene. Other orders of mammals present with totally or mostly carnivorous diets including bats, other insectivores, and some monkeys
1
2
Felines of the World
(chimpanzees, baboons) and prosimians. However, those we will deal with are the carnivores (order Carnivora) that, from a taxonomic point of view, belong to the precise order of mammals and share a common phylogenetic history together with particular anatomical features.
The order of Carnivora includes dogs and wolves, cats and “big cats,” bears, raccoons, weasels, genets, seals, etc.
(A) Eurasian lynx (Lynx lynx linx) order Carnivora, family Felidae. (B) Siberian weasel (Mustela sibirica) order Carnivora, family Mustelidae. (C) Maned wolf (Chrysocyon brachyurus) order Carnivora, family Canidae. This South American species has an omnivorous diet and is particularly greedy for a certain type of wild tomato (Solanum lycocarpum).
Man and carnivores Within the order of Carnivora there are two species of mammals which are the most popular of human pets: the cat and the dog. These are bred everywhere that man has settled; with cats being the most common pet with about 500 million specimens around the world. Dogs, often called “man’s best friend,” is also used as a working animal (for hunting, towing sleds, guarding flocks, etc.) or as guide dogs for the blind, sniffer dogs (police dogs), and for carrying out rescues after avalanches and storms. Their relatives and wild ancestors, namely wolves and the big wild cats, are admired as great hunters, but the relationship with the Carnivora also creates a series of conflicts and a complicated outlook, with opinions that can be very different or even conflicting, in different cultures and in various historical periods. This simple admiration for their strength and beauty has occasionally escalated to a veneration or viewing them as sacred as in many ancient cultural and religious traditions. However, carnivores have also
always been considered as rivals and dangerous competitors, especially when man hunted prey for food; they were and can still be a serious danger to farmers and their livestock, and there is also a conflict over space due to natural and wild environments giving way to agriculture. The invention of hunting as a “sport” as a “test of courage” or to obtain their precious furs, or for other multiple reasons whether selfish, utilitarian, or merely as a convenient petty economy, has reduced many species of carnivores to the point of extinction, especially the larger ones (tiger, lion, bears, wolves, etc.) which need large spaces in which to live together with their prey, with which they play a primary role as predators and/or superpredators, which is an indispensable role in the maintenance of the ecological balance of the natural environment. Many species have been eradicated from most of their natural habitats and relegated to live in restricted protected areas, which are not always sufficient to safeguard their future.
(A) Red tabby (long haired) and (B) Caucasian shepherd dog (a female with four puppies). These are breeds domesticated and bred by man, but which derive from wild carnivores.
Order of carnivores (Carnivora) Chapter | 1
Chapter 1.1 Anatomical features common to order Carnivora The Carnivora are an order of mammals to which belong animals that are almost all adapted to a predominantly carnivorous diet (i.e., they need high percentages of animal proteins obtained from meat and fish meat), and for this reason, their anatomical structure is specialized for predation and in the digestion of this type of food; their “small intestine” is short (three to six times the length of their body) and their digestive enzymes include urate oxidase or uricase, which allows them to digest the uric acid contained in meat. Very few species have subsequently
3
evolved by adapting to an omnivorous diet (composed of different percentages of plant substances and animal substances), such as badgers, bears, and the almost vegetarian, giant and lesser pandas (bamboo eaters), and the aardwolf (Proteles cristata), an Ienidae, and bat-eared fox (Otocyon megalotis), a Canidae, which have an entomophagous or insectivorous diet (termites). Some Canidae, such as the foxes (Vulpes sp.) and the maned wolf (Chrysocyon brachyurus), being opportunistic species, feed abundantly on fruit in the season that they ripen. Felids belong instead to a group described as “hypercarnivorous” as their diet is almost exclusively meat (more than 70%).
The red or lesser panda (Ailurus fulgens) is the only species of the Ailuridae family.
Like the giant panda (family Ursidae), it has an almost vegetarian diet based on bamboo. Both these Asian species, have a sort of “sixth finger” in the front legs, which is the sesamoid bone of the hand, and has the shape and function of an opposable thumb, it is used to grasp bamboo twigs and take them to the mouth. To this order belong minute species weighing as little as 25 g like the least weasel (Mustela nivalis) up to the giant polar bear and Kodiak brown bear, which can exceed 800 kg, although the greatest of all is the enormous southern elephant seal (Mirounga leonina) with a weight of up to 3000 kg. The gait can be plantigrade or digitigrade and the paws are always supplied with strong claw nails. The muscles of the hind legs are often massive, equipped with strong tendons that allow in many cases long leaps and rapid snappy movements (sprinters). In the Pinnipeds (Pinnipedia), earless seals, sea lions (eared seals or otary), and walruses, the limbs are transformed into fins. They have very developed senses, especially sight and hearing, but in some an acute sense of smell prevails as revealed by the development of the nasal mucosa and the olfactory region of the brain, especially in the some
Caniformia and Felidae; the latter also have very acute sight, with eyes suitable for night vision. The following six anatomical features largely define carnivores. 1. All carnivores have elongated and pointed canines with a conical shape called tusks which are used to kill prey; the premolar and molar teeth have a pointed shape with one or more sharp cusps; the so-called carnassial or sectorial teeth are composed of the fourth upper premolar (P4) and the first lower molar (M1), they are larger and very sharp, essential for being able to cut (with a scissor-like action) the muscles and tendons of prey, and to obtain pieces of meat of a size suitable for being ingested. 2. The third upper molar (M3 ) is missing in adult Carnivora dentition. 3. Within the skull it is notable that the braincase (the cerebral portion of the skull) is well rounded and well developed, so that the “frontoparietal suture” of the cranial bones is placed anteriorly. 4. An important characteristic to determine the taxonomic rank in Carnivores is the particular conformation of the bones of the base of the skull; it is here that there is also
4
Felines of the World
the tympanic bulla (auditory bulla), an ovoid hollow bone formation which contains the three hearing bones (the hammer, anvil, and stirrup). Until a few years ago it was believed that the bulla was formed from the tympanic bone only, however, more recent studies have shown instead that its morphogenesis evolved in different ways in the various families of carnivores, and that it may also derive from the fusion of several bones (ectotympanic, rostral, and caudal entotympanics). These different anatomical shapes influence the path of the carotid artery and this set of the features are one of the most important diagnostic factors for the determination of some taxa, including fossil taxa. 5. In the skeleton, the clavicle is missing or very small (vestigial).
6. On the front legs there are always with five digits, often with the first short and vestigial (the dew-claw), which is not used in walking, however, especially in the Felids, it is provided with a hooked claw that is used for predation. There are three small carpal bones (scaphoid, semilunar, and central) that merge into the single bone (“scapholunar”) of the wrist. The hind legs can have four or five digits depending on the gait adopted by the species. Plantigrade species have five digits and digitigrade species four. Felids (cats) and Canidae (dogs and wolves), which include adept cursorial and sprinter species, are digitigrade; meanwhile Ursidi (bears) and Procyonidae (raccoons) which are not cursorials have legs suitable to their plantigrade gait.
(A) In the order of Carnivora the carpal bones (of the front legs), scaphoid and lunar (semilunar), are fused into a single bone, the scapholunar. (B) Within the Carnivora there are various types of gait, plantigrade, semiplantigrade (some Viverridae like Paradoxurus), semidigitigrade (some Mustelidae like the badger), and digitigrade. The digitigrades put only the end phalanges of their digits on the ground, a gait that allows greater speed.
Chapter 1.2 Features of Caniformia and Feliformia The order of Carnivora is composed of 16 families divided into two suborders. 1. The suborder Caniformia, which means “dog-like” includes bears, wolves, raccoons, weasels, etc., and the Clade Pinnipedia. It has evolved with diversification centers that have been found in North America and northern Eurasia; the most ancient fossils found in these continents have anatomical structures adapted to an arboreal life. Today’s representatives of the suborder have largely plantigrade gait, except Canidae which are digitigrade; they tend to have an omnivorous diet and often have a large number of teeth—from 34 (only in
the weasel) to a maximum of 48 50. A diagnostic characteristic is the tympanic bulla, containing a part of the organs of hearing, which is formed by ectotympanic bones and has no internal median septum which divides it into two chambers. In some families including the Canidae and Ursidae, the alisphenoid canal is present and the internal carotid artery is not obstructed by the temporal bone structure and so is not reduced. 2. The suborder Feliformia, which means “cat-like,” includes cats, hyenas, genet, mongooses, Malagasy mongooses, etc. It originated with diversification centers located in Africa and southern Asia, with species with an anatomical structure suitable for an arboreal life. The current species almost all have a
Order of carnivores (Carnivora) Chapter | 1
digitigrade gait (at least in the front legs) and many have nails that are partially retractable or completely retractable, such as the claws of the Felidae. They have a much more carnivorous diet than caniforms and some groups are “hypercarnivorous.” To improve the possibility of predation the most advanced, like some Felidi, has gradually decreased the number of
5
teeth to up to 28 30; in the other Feliformia there can be up to a maximum of 40 teeth. Their tympanic bulla is formed by entotympanic and ectotympanic bones and it is divided into two chambers by a median septum. With the alisphenoid canal absent, the internal carotid artery is reduced because it is obstructed by the bone structure.
Skull of a carnivore showing the basicranial region, where the two auditory or tympanic bullae are seen at the sides of the occipital hole (or foramen magnum).
Feliformia
Caniformia
Section of an auditory bulla of Feliformia Where it is seen that the interior is divided into two parts by a septum
Section of an auditory bulla of Caniformia Where it is seen that the interior is a single chamber, not divided into two parts by a septum
6
Felines of the World
Carnivora denture or dentition Feliformia Few teeth Wild cat (Felis silvestris) skull
Caniformia Many teeth Black-backed jackal (Canis mesomelas) skull
The Feliformia have 28/40 teeth Felidae have 28/30 teeth Hyaenidae have 34 teeth
The Caniformia have 34/48 50 teeth Canidae have 38/42 teeth, but one species has many more
Spotted hyena (Crocuta crocuta). These carnivores have very large teeth and extremely robust jaws to break bones
The Canidae bat-eared fox (Otocyon megalotis) has up to 48/50 teeth, the largest number of teeth among all Carnivora
Viverridae have 32/40 teeth
Ursidae have 40/42 teeth
African civet (Civettictis civetta). The largest of all the Viverridae and the only civet in Africa
Andean or spectacled bear (Tremarctos ornatus). The only South American species of bear
Order of carnivores (Carnivora) Chapter | 1
7
Pink, canine teeth; blue, carnassial teeth (M1) (PM4)
Chapter 1.3 classification
Evolution,
phylogeny,
and
The assumptions made in order to exactly define the period in which the first true Carnivora appeared are sometimes discordant. It had always been asserted that they first appeared in the late Paleocene, but according to the latest fossil discoveries and based on calculations on the evolution of their anatomical characteristics and molecular phylogeny, today it is generally thought that they probably appeared more than 66 million years ago (Mya), at the beginning of Paleocene. It has always been assumed that the fossil forms belonging to the superfamily of Miacoidea were the first true ancestors of modern carnivores. Miacoidea remains are found in Western Europe, Asia, and North America, with some forms that survived for almost the entire Eocene. These evolved into two families: 1. Miacidae with many genera, including Vulpavus, Paroodectes, Miacis, etc. 2. Viverravidae with fewer genera, including Viverravus, Mustelodon, etc. Similar to a cross between small genets and martens, they all presented characteristics typical of arboreal
animals, such as frontal eyes, an elongated skull and body, short legs, long tail, and pointed and retractable claws. Their dentition, typical of carnivores, with long zanniform canines (fang-shaped canines 5 tusk shaped canines) and molars with pointed cusps, was generally composed of 42/44 teeth. However, according to important research in the field of comparative anatomy and paleontology, the true nature of Miacoidea as direct ancestors of the current Carnivora is questioned, with some considering them as only belonging to the Clade of the Carnivoramorpha, which includes the true carnivores, the Miacidae, the Viverravidae, and some forms not well defined from a systematic point of view, including some genera such as Tapocyon and Quercygale (which some authors continue to ascribe to the Miacoidea). Especially Tapocyon, for some of the characteristics of the base of the skull, can perhaps be considered very similar or closely related to the group that originated the true Carnivora. It is, however, quite certain that the first true members of the carnivorous order appeared in Central Asia (perhaps in China) at high latitudes, in regions with a cold temperate climate (Rolland et al., 2015) and there they diversified considerably and then spread to tropical regions later.
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Felines of the World
Shortly after their appearance (after the middle of the Paleocene) the order was immediately differentiated into the two great present suborders: Feliformia and Caniformia. The results of the latest research indicate that the division between Feliformia and Caniformia began between the beginning and the middle of the Paleocene (57 Mya), whereas before it was assumed to be a much later subdivision, in the middle Eocene about 43 Mya.
Later these Taxa gave rise, in addition to the current families of carnivores, also to many important fossil groups (Nimravidae, Amphicyonidae, Percrocutidae, etc.), which are well represented in many fossiliferous sites and were therefore widely diffused in the past, but which became extinct in various successive epochs but allowing some to survive until the beginning of the Pliocene.
Order of carnivores (Carnivora) Chapter | 1
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Miacidae: Paroodectes feisti, which belongs to the “Carnivoramorpha” group. These are animals more or less the size of a genet and with arboreal habits. To this group, that dates back to the Pleistocene, there are many genera and species, some of which represent the true ancestors of the modern carnivores.
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Felines of the World
Blue branches (blue lines), Caniformia, Red branches (red lines), Feliformia Figure from Van Valkenburgh, B., Wayne, R.K., 2010. Carnivores. Curr. Biol. 20(23), 2157. Figure created by G. Slater and J. Pollinger. Van Valkenburgh, B. Pang, B., Bird, D., Curtis, A., Yee, K., Wysocki, C., Craven, B. A., 2014. Respiratory and olfactory turbinals in feliform and caniform carnivorans: the influence of snout length. Anat. Rec. 297, 2065 2079. https:// www.researchgate.net/publication/266857277.
Order of carnivores (Carnivora) Chapter | 1
https://upload.wikimedia.org/wikipedia/commons/c/c3/Carnivora_phylogeny_%28eng%29.png
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Felines of the World
After a long evolutionary history, Caniformia and Feliformia have evolved into the current 16 families composed of about 286 species. These are widespread in almost all the natural and anthropized environments of the Earth, from the Arctic tundra to the tropical forests, in deserts, wetlands, and the sea. The carnivores have reached and colonized all the continents except Australia,
but even here they are still present, with at least one species of feral dog, the dingo, imported in prehistoric times (3000 4000 years ago) from Indochina and the Sunda islands by man, but that has now assumed a well-defined ecological role in some Australian ecosystems.