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A small, “wader-like” bird from the Early Eocene of Messel (Germany)
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Original article
A small, “wader-like” bird from the Early Eocene of Messel (Germany) Un petit oiseau de type échassier de l’Éocène Inférieur de Messel (Allemagne) Gerald Mayr Senckenberg Research Institute and Natural History Museum Frankfurt, Ornithological Section, 25, Senckenberganlage, 60325 Frankfurt am Main, Germany
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Article history: Received 30 November 2016 Accepted 10 January 2017 Available online xxx Keywords: Aves Fossil birds Charadriiformes Jacanidae Songziidae Vanolimicola longihallucis gen. et sp. nov.
a b s t r a c t A small bird with a shorebird-like beak and a very long hind toe is described from the Early Eocene of Messel in Germany. Vanolimicola longihallucis, gen. et sp. nov. is one of the few candidate species for a “wading bird” from Messel, that is, a bird that may have foraged along the shoreline of the ancient lake. A few features indicate a relationship to charadriiform birds and Jacanidae (jacanas) in particular, but charadriiform affinities are only weakly supported. In the preserved skeletal elements, V. longihallucis also resembles the taxon Songzia from the Early Eocene of China, which is considered to be a representative of the Ralloidea (rails and allies). A potential biogeographic significance of the new Messel fossil is strengthened by similar fossils from the North American Green River Formation. © 2017 Elsevier Masson SAS. All rights reserved.
r é s u m é Mots clés : Aves Oiseaux fossiles Charadriiformes Jacanidae Songziidae Vanolimicola longihallucis, gen. et sp. nov.
Un petit oiseau avec un bec d’oiseau de rivage et un orteil postérieur très long est décrit de l’Éocène Inférieur de Messel en Allemagne. Vanolimicola longihallucis, gen. et sp. nov. est l’un des rares candidats au type « échassier » de Messel, c’est-à-dire un oiseau qui a pu se nourrir le long de la rive de l’ancien lac. Quelques traits indiquent une relation avec les Charadriiformes, et les Jacanidae (jacanas) en particulier, mais les affinités avec les oiseaux charadriiformes ne sont que faiblement basées. De par les éléments squelettiques préservés, V. longihallucis ressemble également au taxon Songzia de l’Éocène Inférieur de Chine, qui est considéré comme un représentant des Ralloidea (râles et formes apparentées). Une signification biogéographique potentielle du nouveau fossile de Messel est renforcée par des fossiles semblables provenant de la Formation de la Green River en Amérique du Nord. ´ ´ es. © 2017 Elsevier Masson SAS. Tous droits reserv
1. Introduction In the past decades, the Early Eocene avifauna of the German fossil site Messel has been intensely studied and about 70 species are currently known, not all of which have been named. Although the fossil-bearing oilshale of the locality originated in a crater lake, the site is notable for the paucity of aquatic or semi-aquatic birds, with most of the avian remains belonging to terrestrial or arboreal taxa (Mayr, 2016a, in press a). Here, a partial skeleton of a small bird is described, which was found in 1984 and has not been studied so far. The fossil was
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originally identified as a limicoline charadriiform on the specimen label, but as detailed in this study an assignment to an extant avian higher-level taxon is not straightforward. A few osteological features hint at possible affinities with the Jacanidae (jacanas or lily trotters), an aberrant group of pantropical Charadriiformes. Compared with other Early Eocene birds, however, the new specimen from Messel also resembles the taxon Songzia from the Early Eocene (Bumbanian) of China. The two species of this taxon, S. heidangkouensis and S. acutunguis, are both from the Yangxi Formation of Hubei province and are considered to be most closely related to Ralloidea, the clade including Rallidae and Heliornithidae (Hou, 1990; Wang et al., 2012). Although the new bird from Messel is only based on a partial skeleton, the find has potential paleoecological and
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Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001
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Fig. 1. Holotype of Vanolimicola longihallucis, gen. et sp. nov. from the Early Eocene of Messel. A, SMNK.PAL 8683a. B, SMNK.PAL 8683b. The fossils were coated with ammonium chloride. Scale bars equal 10 mm. Holotype de Vanolimicola longihallucis, gen. et sp. nov. de l’Eocène Inférieur de Messel. A, SMNK.PAL 8683a. B, SMNK.PAL 8683b. Les fossiles ont été recouverts de chlorure d’ammonium. Les échelles représentent 10 mm.
paleobiogeographic implications that justify its publication. Clearly, it represents a taxon not yet reported from the Messel avifauna and is one of the few candidates for a semi-aquatic bird known from the locality. The similarity to Songzia furthermore suggests a potential biogeographic significance of the new Messel fossil, which, as detailed below, is strengthened by the occurrence of similar fossils from the North American Green River Formation.
Museum of Natural History, Chicago, USA (FMNH). All measurements are in millimeters.
3. Systematic Palaeontology
2. Material and methods
Class Aves Linnaeus, 1758 Family cf. Jacanidae Stejneger, 1885 and Songziidae Hou, 1990 Genus Vanolimicola, gen. nov.
The fossils are deposited in Staatliches Museum für Naturkunde, Karlsruhe, Germany (SMNK), the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China (IVPP), and the Field
Type genus: Vanolimicola longihallucis, gen. et sp. nov. Differential diagnosis: The new taxon is characterized by
Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001
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Fig. 2. A, B: skull of Vanolimicola longihallucis, gen. et sp. nov. (holotype, A: SMNK.PAL 8683a; B: SMNK.PAL 8683b). The inset in A shows a digitally highlighted section of the beak, the inset in B shows the digitally highlighted quadrate and mandible (white frame). C-E, skulls of C: Songzia acutunguis (Songziidae) from the Early Eocene of China (IVPP 18188), D: the Tawny-throated Dotterel, Oreopholus ruficollis (Charadriidae), and E: the Wattled Jacana, Jacana jacana (Jacanidae). Abbreviations: cnb, caudal nasal bar; fcm, fenestra caudalis mandibulae; frm, fenestra rostralis mandibulae; hyo, hyoid apparatus; lmd, caudal end of left mandible; lqd, left quadrate; nos, nostril; rqd, right quadrate. Fossils in A and B were coated with ammonium chloride. Scale bars equal 5 mm. A, B :crâne de Vanolimicola longihallucis, gen. et sp. nov. (holotype, A : SMNK.PAL 8683a ; B : SMNK.PAL 8683b). L’encadré en A montre une section du bec, accentuée numériquement ; l’encadré en B montre le carré et la mandibule (cadre blanc), accentuée numériquement. C–E : crânes de C, Songzia acutunguis (Songziidae) de l’Eocène Inférieur de Chine (IVPP 18188), D : du Pluvier oréophile, Oreopholus ruficollis (Charadriidae) et E : du Jacana noir Jacana jacana (Jacanidae). Abréviations : cnb, barre nasale caudale ; fcm, fenestra caudalis mandibulae ; frm, fenestra rostralis mandibulae ; hyo, appareil hyoïdien ; lmd, extrémité caudale de la mandibule gauche ; lqd, carré gauche ; nos, narine ; rqd, carré droit. Les fossiles en A et B ont été recouverts de chlorure d’ammonium. Les échelles représentent 5 mm.
• a long, pointed, and probably schizorhinal beak with long nostrils, • a long tarsometatarsus, and • a very long hallux, whose first phalanx exceeds all other pedal phalanges in length. It differs from the Early Eocene Songzia Hou, 1990 in the proportionally longer and narrower beak, the proportionally longer hallux (which distinctly exceeds the proximal phalanx of the second toe in Vanolimicola, but is slightly shorter than this phalanx in Songzia), and the proportionally shorter fore toes (whereas the third toe approaches the length of the tarsometatarsus in Songzia, it is distinctly shorter than the tarsometatarsus in Vanolimicola). Etymology: The name is derived from vanum (Lat.), appearance, and Limicola, a taxon of “limicoline” Charadriiformes, in reference to the wader-like overall morphology of the new taxon. Vanolimicola longihallucis, gen. et sp. nov. Holotype: SMNK.PAL 8683a + b (partial skeleton on two slabs; Fig. 1).
Diagnosis: As for genus. Type locality and horizon: Messel near Darmstadt, Germany; late Early Eocene (48 million years ago; Lenz et al., 2015). Measurements (left [l] and right [r]): Skull, 35.2; humerus (estimated), ∼18 (l); carpometacarpus, ∼9.5 (r, estimated); femur, ∼20 (r); tibiotarsus, 32.4 (r); tarsometatarsus, 21.2 (l), 21.0 (r). Pedal phalanges: I1, 6.6 (l); I2, 2.5 (l); II1, 5.4 (l); II2, 3.8 (r); II3, 3.8 (r); III1, > 4.8 (l), ∼5.0 (r); III2, 4.8 (l), ∼4.9 (r); III3, 4.2 (r); III4, 2.9 (r); IV1,–; IV2, ∼2.9 (l); IV3, 2.7 (l), 2.6 (r); IV4, 2.7 (l), 2.5 (r); IV5, 2.0 (r). Etymology: The species epithet refers to the long hallux of the new species. Remarks: Vanolimicola longihallucis, gen. et sp. nov. is clearly distinguished from all other avian species known from Messel and a potential confusion is only possible with the long-legged, zygodactyl Primozygodactylus, which is a stem group representative of Passeriformes (Mayr, 2009, 2016, in press b). In spite of similar length proportions of the leg bones, V. longihallucis differs from zygodactylids in the narrower beak, the proportionally longer carpometacarpus, the much longer hallux (longer than the
Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001
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Fig. 3. Osteological details of Vanolimicola longihallucis, gen. et sp. nov. A: left humerus in caudal view (SMNK.PAL 8683b); note that the entire proximal half of the bone is only preserved as a resin cast. B: left humerus (caudal view) of the Wattled Jacana, Jacana jacana (Jacanidae). C: right humerus in caudal view (SMNK.PAL 8683b). D: hand section of right wing in ventral view (SMNK.PAL 8683b). E: cervical vertebrae (SMNK.PAL 8683b). F: pelvic region in ventral view (SMNK.PAL 8683a). G: proximal end of right tibiotarsus (SMNK.PAL 8683a). Abbreviations: ccc, crista cnemialis cranialis; fem, femur; dep, depression in cranial end of synsacrum; flx, processus flexorius; fvd, foramen vasculare distale; ocu, os carpi ulnare; pdm, phalanx proximalis digiti majoris; mtI, os metatarsale I; prj, ventral projection on proximal end of os metacarpale minus; psd,
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first phalanx of the third toe in V. longihallucis, but much shorter in Primozygodactylus), and the presumed absence of zygodactyl feet (as deduced from the preserved position of the fourth toe). Description and comparisons: Although the holotype skeleton is fragmentary and not well preserved, it allows the recognition of characteristic osteological details. In skull proportions, Vanolimicola longihallucis, gen. et sp. nov. resembles some extant plovers (Charadriiformes, Charadriiformes), especially the South American Tawny-throated Dotterel (Oreopholus ruficollis), in which the beak is, however, proportionally somewhat longer (Fig. 2D). The needle-like beak of V. longihallucis measures about half of the entire skull length and is dorsoventrally narrow, with a straight culmen and a pointed, mediolaterally narrow tip. The nostrils are very long, but their exact length is difficult to determine, because it is uncertain whether a furrow in the distal portion of the beak represents the distal section of the nostril or the collapsed rostrum maxillae. The proximal end of the nostril appears to have been slit-like, therefore indicating a schizorhinal condition and a rhynchokinetic beak. Owing to the dorsoventrally narrow upper beak, the caudal nasal bar is more obliquely oriented than in many extant schizorhinal Charadriiformes. The mandible exhibits a long and slitlike fenestra rostralis mandibulae and a small, subcircular fenestra caudalis mandibulae; the caudal end seems to lack the distinct, dorsally directed process that is characteristic for many crown group charadriiforms (Fig. 2). The left quadrate is visible in caudal view, the right one in lateral view (Fig. 2). Taxonomically significant details of the bone, however, cannot be discerned. Although the fossil preserves elements of the hyoid apparatus (Fig. 2A), no ossified tracheal rings are visible. The cervical vertebrae (Fig. 3E) are of average proportions and neither very long nor very short, with deep lacunae interzygapophysiales. The number of praesacral vertebrae cannot be determined and no features of phylogenetic significance are visible. The ventral surface of the cranial end of the synsacrum bears a pair of shallow, lateral depressions (Fig. 3F), but whether these indicate pleurocoelous thoracic vertebrae (a characteristic feature of charadriiform birds, in which the thoracic vertebrae bear deep lateral depressions) cannot be said. Few details of the fragmentary wing and pectoral girdle elements are discernible. Of both humeri, only the distal portions are preserved as bone substance. The outline of the proximal end of the left humerus is, however, traced by a resin cast of the void left by the bone in the original matrix (like most Messel fossils, the specimen was prepared with the resin transfer method) and allows the recognition of a fairly large tuberculum dorsale (Fig. 3A). The distal end of the left humerus bears a small processus supracondylaris dorsalis, whose tip is broken (Fig. 3A). A processus supracondylaris dorsalis characterizes charadriiform birds, but in SMNK.PAL 8683 the process is much smaller than in most extant charadriiform taxa (in Jacanidae, this process is, however, likewise only weakly developed; Fig. 3B). On the right humerus, a well-developed processus flexorius is visible (Fig. 3C). Both ulnae lack the distal portions, with the distal end of the left ulna having been on a missing part of the slab, whereas the distal right ulna appears to exhibit a perimortem fracture. Only the right carpometacarpus is preserved and lacks its proximal portion. The bone is fairly long, with a narrow
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spatium intermetacarpale and a long symphysis metacarpalis distalis (Fig. 3D). The proximal end of the os metacarpale minus forms a small ventral projection. The phalanx proximalis digiti majoris is of average proportions. Except for a portion of the right scapula, elements of the pectoral girdle are not visible, and remains of the wing and tail feathers are likewise not preserved. Overall and as far as comparisons are possible, the wing bones correspond well with those of Songzia, although critical bone sections, such as the distal end of the humerus, are not well preserved in the Songzia fossils (Wang et al., 2012). The leg bones are more complete, but the poor preservation of the specimen impedes the recognition of osteological details. The crista cnemialis cranialis of the tibiotarsus (Fig. 3G) is only moderately prominent and less developed than in most charadriiform birds; the condylus medialis (Fig. 4A) is fairly large and its proximodistal length exceeds the minimum mediolateral width of the tibiotarsus shaft. The tarsometatarsus (Fig. 4) is long and slender. The hypotarsus of the right tarsometatarsus is visible in medial (SMNK.PAL 8683b) and lateral (SMNK.PAL 8683a) view. It is proximodistally short, with moderate plantar prominence, and has a similar shape to the hypotarsus of charadriiform birds. The foramen vasculare distale on the distal end of the bone is very large (Fig. 4B). Details of the tarsometatarsal trochleae cannot be seen. The tarsometatarsus of Songzia has similar overall proportions to that of Vanolimicola, but the size of the foramen vasculare distale is not clearly visible in the known specimens. The toes exhibit a characteristic morphology. Most notably, the hallux is unusually long, reaching almost one third of the length of the tarsometatarsus, and its first phalanx is markedly curved. The third toe measures slightly less than the length of the tarsometatarsus. The fourth phalanx of the fourth toe has about the same length as the third phalanx, which characterizes Charadriiformes and a few other extant avian groups (e.g., Otididae; Hesse, 1988). The ungual phalanges are relatively long and straight.
4. Discussion The holotype of Vanolimicola longihallucis, gen. et sp. nov. is fragmentary and not well preserved, but the comparatively long legs and the “limicoline” beak prompt comparisons with Charadriiformes and suggest that V. longihallucis was foraging in the shore area of the Messel lake. The only previous record of a putative charadriiform bird from Messel was described by Mayr (2000). This fossil stems from an unnamed species and consists of wing and pectoral girdle elements, so that only few meaningful comparisons with the V. longihallucis holotype are possible. With a carpometacarpus length of 17.2 mm, the specimen is, however, much larger than V. longihallucis. The new species agrees with Charadriiformes in the proportions of the phalanges of the fourth toe, with the fourth phalanx being of subequal length to the third (Hesse, 1988). In birds, the fourth phalanx of the fourth toe is usually longer than the third, but in some taxa, the proportions of this phalanx are variable, which diminishes the phylogenetic significance of the character (e.g., whereas the fourth phalanx of the fourth toe is distinctly longer than the
processus supracondylaris dorsalis; rad, radius; smd, symphysis metacarpalis distalis; syn, synsacrum; tbd, tuberculum dorsale; tbt, tibiotarsus; tho, thoracic vertebra; uln, ulna. Fossils were coated with ammonium chloride. Scale bars equal 5 mm. Détails ostéologiques de Vanolimicola longihallucis, gen. et sp. nov. A : humérus gauche en vue caudale (SMNK.PAL 8683b) ; noter que toute la moitié proximale de l’os est seulement préservée sous forme de coulée de résine. B : humérus gauche (vue caudale) de Jacana noir, Jacana jacana (Jacanidae). C : humérus droit en vue caudale (SMNK.PAL 8683b). D : portion distale (main) de l’aile droite en vue ventrale (SMNK.PAL 8683b). E :vertèbres cervicales (SMNK.PAL 8683b). F : région pelvienne en vue ventrale (SMNK.PAL 8683a). G : extrémité proximale du tibiotarsus droit (SMNK.PAL 8683a). Abréviations : ccc, crista cnemialis cranialis ; fem, fémur ; dep, dépression à l’extrémité crânienne du synsacrum ; flx, processus flexorius ; fvd, foramen vasculare distale ; ocu, os carpi ulnare ; pdm, phalanx proximalis digiti majoris ; mtI, os metatarsale I ; prj, projection ventrale à l’extrémité proximale de l’os metacarpale minus ; psd, processus supracondylaris dorsalis ; rad, radius ; smd, symphysis metacarpalis distalis ; syn, synsacrum ; tbd, tuberculum dorsale ; tbt, tibiotarsus ; tho, vertèbre thoracique ; uln, ulna. Les fossiles ont été recouverts de chlorure d’ammonium. Les échelles représentent 5 mm.
Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001
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Fig. 4. Feet of Vanolimicola longihallucis, gen. et sp. nov. A: left foot in dorsal view (SMNK.PAL 8683a). B: detail of distal end of left foot (SMNK.PAL 8683a). C, D: right foot in lateral (SMNK.PAL 8683a) and medial (SMNK.PAL 8683b) view. E: left tarsometatarsus of the Wattled Jacana, Jacana jacana (Jacanidae). F: left foot of Songzia acutunguis (Songziidae) from the Early Eocene of China (IVPP 18188). G: right foot (dorsal view) of the African Jacana, Actophilornis africanus (Jacanidae; the ungual phalanx of the third toe is broken and lacks its tip). Abbreviations: cdm, condylus medialis; fvd, foramen vasculare distale. The toes are numbered. Fossils in A–D were coated with ammonium chloride. Scale bars equal 5 mm. Pieds de Vanolimicola longihallucis, gen. et sp. nov. A : pied gauche en vue dorsale (SMNK.PAL 8683a). B : détail de l’extrémité distale du pied gauche (SMNK.PAL 8683a). C, D : pied droit en vue latérale (SMNK.PAL 8683a) et médiane (SMNK.PAL 8683b). E : tarsometatarsus gauche de Jacana noir, Jacana jacana (Jacanidae). F : pied gauche de Songzia acutunguis (Songziidae) de l’Eocène Inférieur de Chine (IVPP 18188). G: pied droit (vue dorsale) de Jacana à poitrine dorée, Actophilornis africanus (Jacanidae, la phalange unguéale du troisième orteil est cassée et son extrémité distale manque). Abréviations : cdm, condylus medialis ; fvd, foramen vasculare distale. Les orteils sont numérotés. Les fossiles en A–D ont été recouverts de chlorure d’ammonium. Les échelles représentent 5 mm.
third in most Rallidae, both phalanges are of subequal length in Himantornis haematopus and Canirallus oculeus). Concerning the unusually long hallux, V. longihallucis clearly differs from most extant Charadriiformes, in which the hind toe is short to very short. A very long hallux is only found in Jacanidae, with which V. longihallucis also agrees in the large foramen vasculare distale of the tarsometatarsus, which is, however, even larger in the Jacanidae. As in Vanolimicola and unlike in most other charadriiform birds, the processus supracondylaris dorsalis of the humerus is only weakly developed in extant Jacanidae. In contrast
to Vanolimicola, however, jacanas also have very long fore toes with extremely elongated ungual phalanges, which enable these birds to walk on floating vegetation (Fig. 4G). The legs of jacanas are furthermore proportionally longer than those of Vanolimicola, with the tibiotarsus distinctly exceeding the skull in length. All of these differences may well be due to the possibility that Vanolimicola is a very early stem group representative of jacanids, in which case it would be the oldest fossil record of the group, with the earliest definitive Jacanidae being from the Late Eocene of Egypt (Rasmussen et al., 1987; Mayr, 2016b).
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Currently, however, an assignment of V. longihallucis to Jacanidae is not strongly based and compared with other Eocene birds, the new species also resembles the taxon Songzia from the Bumbanian of China (Hou, 1990; Wang et al., 2012). Like Vanolimicola, Songzia has a very long hallux, although the three fore toes of the Chinese taxon are proportionally longer than those of Vanolimicola. The nostrils of S. acutunguis appear to have been holorhinal, but their caudal ends are not well visible in the two known specimens. Songzia has proportionally shorter wings than Jacanidae and other charadriiform birds, and unlike in Charadriiformes the ulna does not exceed the humerus in length. In fact, the relative length of the ulna is a feature that readily distinguishes Jacanidae and all other extant representatives of Charadriiformes from the Ralloidea. Unfortunately, humerus and ulna are very fragmentary in the V. longihallucis holotype, and their relative lengths cannot be assessed. Future specimens with well preserved wing bones are therefore needed to further evaluate the affinities between V. longihallucis and either Jacanidae or Songziidae. With an age of 55.8–54.8 million years (Ni et al., 2013), the Songzia fossils are about 7 million years older than V. longihallucis from Messel. It should finally be mentioned that there exists an undescribed fossil from the Green River Formation, which was figured by Grande (2013: Fig. 143A, top right, FMNH PA 728) and shows some overall similarity to V. longihallucis. This North American fossil likewise features long nostrils and a long hallux, but with a skull length of 44 mm (Grande, 2013), it is from a larger species. Unlike in V. longihallucis, the fourth phalanx of the fourth toe is furthermore longer than the third, and the nostrils have a rounded caudal margin and are therefore holorhinal. Grande (2013: Fig. 143A, bottom right) referred a second specimen from the Green River Formation (FMNH PA 756) to the same undescribed species, but detailed studies of these fossils are required for an assessment of possible affinities to V. longihallucis. Disclosure of interest
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Acknowledgements I thank Eberhard Frey (SMNK) for the loan of the fossil and Sven Tränkner for photographs of the Messel specimen; the Songzia photos were taken by Min Wang (IVPP). Lance Grande (FMNH) is thanked for a photo of the Vanolimicola-like fossil from the Green River Formation. Comments from Vanesa De Pietri and an anonymous reviewer improved the manuscript. References Grande, L., 2013. The lost world of fossil lake. Snapshots from deep time. University of Chicago Press, Chicago. Hesse, A., 1988. Taxonomie der Ordnung Gruiformes (Aves) nach osteologischen morphologischen Kriterien unter besonderer Berücksichtigung der Messelornithidae Hesse, 1988. Courier Forschungsinstitut Senckenberg 107, 235–247. Hou, L.H., 1990. An Eocene bird from Songzi. Hubei province. Vertebrata PalAsiatica 28, 34–42. Lenz, O.K., Wilde, V., Mertz, D.F., Riegel, W., 2015. New palynology-based astronomical and revised 40Ar/39Ar ages for the Eocene maar lake of Messel (Germany). International Journal of Earth Sciences 104, 873–889. Mayr, G., 2000. Charadriiform birds from the early Oligocene of Céreste (France) and the Middle Eocene of Messel (Hessen Germany). Geobios 33, 625–636. Mayr, G., 2009. Paleogene fossil birds. Springer, Heidelberg. Mayr, G., 2016a. Fragmentary but distinctive: three new avian species from the early Eocene of Messel, with the earliest record of medullary bone in a Cenozoic bird. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 279, 273–286. Mayr, G., 2016b. Avian evolution: the fossil record of birds and its paleobiological significance. Wiley-Blackwell, Chichester. Mayr, G., in press a. The early Eocene birds of the Messel fossil site: a 48 million-yearold bird community adds a temporal perspective to the evolution of tropical avifaunas. Biological Reviews. 10.1111/brv.12274. Mayr, G., in press b. New species of Primozygodactylus from Messel and the ecomorphology and evolutionary significance of early Eocene zygodactylid birds (Aves, Zygodactylidae). Historical Biology.10.1080/08912963.2016.1261135. Ni, X., Gebo, D.L., Dagosto, M., Meng, J., Tafforeau, P., Flynn, J.J., Beard, K.C., 2013. The oldest known primate skeleton and early haplorhine evolution. Nature 498, 60–64. Rasmussen, D.T., Olson, S.L., Simons, E.L., 1987. Fossil birds from the Oligocene Jebel Qatrani Formation, Fayum Province. Egypt. Smithsonian Contributions to Paleobiology 62, 1–20. Wang, M., Mayr, G., Zhang, J., Zhou, Z., 2012. Two new skeletons of the enigmatic, rail-like avian taxon Songzia Hou, 1990 (Songziidae) from the early Eocene of China. Alcheringa 36, 487–499.
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Original article
A small, “wader-like” bird from the Early Eocene of Messel (Germany) Un petit oiseau de type échassier de l’Éocène Inférieur de Messel (Allemagne) Gerald Mayr Senckenberg Research Institute and Natural History Museum Frankfurt, Ornithological Section, 25, Senckenberganlage, 60325 Frankfurt am Main, Germany
a r t i c l e
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Article history: Received 30 November 2016 Accepted 10 January 2017 Available online xxx Keywords: Aves Fossil birds Charadriiformes Jacanidae Songziidae Vanolimicola longihallucis gen. et sp. nov.
a b s t r a c t A small bird with a shorebird-like beak and a very long hind toe is described from the Early Eocene of Messel in Germany. Vanolimicola longihallucis, gen. et sp. nov. is one of the few candidate species for a “wading bird” from Messel, that is, a bird that may have foraged along the shoreline of the ancient lake. A few features indicate a relationship to charadriiform birds and Jacanidae (jacanas) in particular, but charadriiform affinities are only weakly supported. In the preserved skeletal elements, V. longihallucis also resembles the taxon Songzia from the Early Eocene of China, which is considered to be a representative of the Ralloidea (rails and allies). A potential biogeographic significance of the new Messel fossil is strengthened by similar fossils from the North American Green River Formation. © 2017 Elsevier Masson SAS. All rights reserved.
r é s u m é Mots clés : Aves Oiseaux fossiles Charadriiformes Jacanidae Songziidae Vanolimicola longihallucis, gen. et sp. nov.
Un petit oiseau avec un bec d’oiseau de rivage et un orteil postérieur très long est décrit de l’Éocène Inférieur de Messel en Allemagne. Vanolimicola longihallucis, gen. et sp. nov. est l’un des rares candidats au type « échassier » de Messel, c’est-à-dire un oiseau qui a pu se nourrir le long de la rive de l’ancien lac. Quelques traits indiquent une relation avec les Charadriiformes, et les Jacanidae (jacanas) en particulier, mais les affinités avec les oiseaux charadriiformes ne sont que faiblement basées. De par les éléments squelettiques préservés, V. longihallucis ressemble également au taxon Songzia de l’Éocène Inférieur de Chine, qui est considéré comme un représentant des Ralloidea (râles et formes apparentées). Une signification biogéographique potentielle du nouveau fossile de Messel est renforcée par des fossiles semblables provenant de la Formation de la Green River en Amérique du Nord. ´ ´ es. © 2017 Elsevier Masson SAS. Tous droits reserv
1. Introduction In the past decades, the Early Eocene avifauna of the German fossil site Messel has been intensely studied and about 70 species are currently known, not all of which have been named. Although the fossil-bearing oilshale of the locality originated in a crater lake, the site is notable for the paucity of aquatic or semi-aquatic birds, with most of the avian remains belonging to terrestrial or arboreal taxa (Mayr, 2016a, in press a). Here, a partial skeleton of a small bird is described, which was found in 1984 and has not been studied so far. The fossil was
E-mail address: [email protected]
originally identified as a limicoline charadriiform on the specimen label, but as detailed in this study an assignment to an extant avian higher-level taxon is not straightforward. A few osteological features hint at possible affinities with the Jacanidae (jacanas or lily trotters), an aberrant group of pantropical Charadriiformes. Compared with other Early Eocene birds, however, the new specimen from Messel also resembles the taxon Songzia from the Early Eocene (Bumbanian) of China. The two species of this taxon, S. heidangkouensis and S. acutunguis, are both from the Yangxi Formation of Hubei province and are considered to be most closely related to Ralloidea, the clade including Rallidae and Heliornithidae (Hou, 1990; Wang et al., 2012). Although the new bird from Messel is only based on a partial skeleton, the find has potential paleoecological and
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Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001
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Fig. 1. Holotype of Vanolimicola longihallucis, gen. et sp. nov. from the Early Eocene of Messel. A, SMNK.PAL 8683a. B, SMNK.PAL 8683b. The fossils were coated with ammonium chloride. Scale bars equal 10 mm. Holotype de Vanolimicola longihallucis, gen. et sp. nov. de l’Eocène Inférieur de Messel. A, SMNK.PAL 8683a. B, SMNK.PAL 8683b. Les fossiles ont été recouverts de chlorure d’ammonium. Les échelles représentent 10 mm.
paleobiogeographic implications that justify its publication. Clearly, it represents a taxon not yet reported from the Messel avifauna and is one of the few candidates for a semi-aquatic bird known from the locality. The similarity to Songzia furthermore suggests a potential biogeographic significance of the new Messel fossil, which, as detailed below, is strengthened by the occurrence of similar fossils from the North American Green River Formation.
Museum of Natural History, Chicago, USA (FMNH). All measurements are in millimeters.
3. Systematic Palaeontology
2. Material and methods
Class Aves Linnaeus, 1758 Family cf. Jacanidae Stejneger, 1885 and Songziidae Hou, 1990 Genus Vanolimicola, gen. nov.
The fossils are deposited in Staatliches Museum für Naturkunde, Karlsruhe, Germany (SMNK), the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China (IVPP), and the Field
Type genus: Vanolimicola longihallucis, gen. et sp. nov. Differential diagnosis: The new taxon is characterized by
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Fig. 2. A, B: skull of Vanolimicola longihallucis, gen. et sp. nov. (holotype, A: SMNK.PAL 8683a; B: SMNK.PAL 8683b). The inset in A shows a digitally highlighted section of the beak, the inset in B shows the digitally highlighted quadrate and mandible (white frame). C-E, skulls of C: Songzia acutunguis (Songziidae) from the Early Eocene of China (IVPP 18188), D: the Tawny-throated Dotterel, Oreopholus ruficollis (Charadriidae), and E: the Wattled Jacana, Jacana jacana (Jacanidae). Abbreviations: cnb, caudal nasal bar; fcm, fenestra caudalis mandibulae; frm, fenestra rostralis mandibulae; hyo, hyoid apparatus; lmd, caudal end of left mandible; lqd, left quadrate; nos, nostril; rqd, right quadrate. Fossils in A and B were coated with ammonium chloride. Scale bars equal 5 mm. A, B :crâne de Vanolimicola longihallucis, gen. et sp. nov. (holotype, A : SMNK.PAL 8683a ; B : SMNK.PAL 8683b). L’encadré en A montre une section du bec, accentuée numériquement ; l’encadré en B montre le carré et la mandibule (cadre blanc), accentuée numériquement. C–E : crânes de C, Songzia acutunguis (Songziidae) de l’Eocène Inférieur de Chine (IVPP 18188), D : du Pluvier oréophile, Oreopholus ruficollis (Charadriidae) et E : du Jacana noir Jacana jacana (Jacanidae). Abréviations : cnb, barre nasale caudale ; fcm, fenestra caudalis mandibulae ; frm, fenestra rostralis mandibulae ; hyo, appareil hyoïdien ; lmd, extrémité caudale de la mandibule gauche ; lqd, carré gauche ; nos, narine ; rqd, carré droit. Les fossiles en A et B ont été recouverts de chlorure d’ammonium. Les échelles représentent 5 mm.
• a long, pointed, and probably schizorhinal beak with long nostrils, • a long tarsometatarsus, and • a very long hallux, whose first phalanx exceeds all other pedal phalanges in length. It differs from the Early Eocene Songzia Hou, 1990 in the proportionally longer and narrower beak, the proportionally longer hallux (which distinctly exceeds the proximal phalanx of the second toe in Vanolimicola, but is slightly shorter than this phalanx in Songzia), and the proportionally shorter fore toes (whereas the third toe approaches the length of the tarsometatarsus in Songzia, it is distinctly shorter than the tarsometatarsus in Vanolimicola). Etymology: The name is derived from vanum (Lat.), appearance, and Limicola, a taxon of “limicoline” Charadriiformes, in reference to the wader-like overall morphology of the new taxon. Vanolimicola longihallucis, gen. et sp. nov. Holotype: SMNK.PAL 8683a + b (partial skeleton on two slabs; Fig. 1).
Diagnosis: As for genus. Type locality and horizon: Messel near Darmstadt, Germany; late Early Eocene (48 million years ago; Lenz et al., 2015). Measurements (left [l] and right [r]): Skull, 35.2; humerus (estimated), ∼18 (l); carpometacarpus, ∼9.5 (r, estimated); femur, ∼20 (r); tibiotarsus, 32.4 (r); tarsometatarsus, 21.2 (l), 21.0 (r). Pedal phalanges: I1, 6.6 (l); I2, 2.5 (l); II1, 5.4 (l); II2, 3.8 (r); II3, 3.8 (r); III1, > 4.8 (l), ∼5.0 (r); III2, 4.8 (l), ∼4.9 (r); III3, 4.2 (r); III4, 2.9 (r); IV1,–; IV2, ∼2.9 (l); IV3, 2.7 (l), 2.6 (r); IV4, 2.7 (l), 2.5 (r); IV5, 2.0 (r). Etymology: The species epithet refers to the long hallux of the new species. Remarks: Vanolimicola longihallucis, gen. et sp. nov. is clearly distinguished from all other avian species known from Messel and a potential confusion is only possible with the long-legged, zygodactyl Primozygodactylus, which is a stem group representative of Passeriformes (Mayr, 2009, 2016, in press b). In spite of similar length proportions of the leg bones, V. longihallucis differs from zygodactylids in the narrower beak, the proportionally longer carpometacarpus, the much longer hallux (longer than the
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Fig. 3. Osteological details of Vanolimicola longihallucis, gen. et sp. nov. A: left humerus in caudal view (SMNK.PAL 8683b); note that the entire proximal half of the bone is only preserved as a resin cast. B: left humerus (caudal view) of the Wattled Jacana, Jacana jacana (Jacanidae). C: right humerus in caudal view (SMNK.PAL 8683b). D: hand section of right wing in ventral view (SMNK.PAL 8683b). E: cervical vertebrae (SMNK.PAL 8683b). F: pelvic region in ventral view (SMNK.PAL 8683a). G: proximal end of right tibiotarsus (SMNK.PAL 8683a). Abbreviations: ccc, crista cnemialis cranialis; fem, femur; dep, depression in cranial end of synsacrum; flx, processus flexorius; fvd, foramen vasculare distale; ocu, os carpi ulnare; pdm, phalanx proximalis digiti majoris; mtI, os metatarsale I; prj, ventral projection on proximal end of os metacarpale minus; psd,
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first phalanx of the third toe in V. longihallucis, but much shorter in Primozygodactylus), and the presumed absence of zygodactyl feet (as deduced from the preserved position of the fourth toe). Description and comparisons: Although the holotype skeleton is fragmentary and not well preserved, it allows the recognition of characteristic osteological details. In skull proportions, Vanolimicola longihallucis, gen. et sp. nov. resembles some extant plovers (Charadriiformes, Charadriiformes), especially the South American Tawny-throated Dotterel (Oreopholus ruficollis), in which the beak is, however, proportionally somewhat longer (Fig. 2D). The needle-like beak of V. longihallucis measures about half of the entire skull length and is dorsoventrally narrow, with a straight culmen and a pointed, mediolaterally narrow tip. The nostrils are very long, but their exact length is difficult to determine, because it is uncertain whether a furrow in the distal portion of the beak represents the distal section of the nostril or the collapsed rostrum maxillae. The proximal end of the nostril appears to have been slit-like, therefore indicating a schizorhinal condition and a rhynchokinetic beak. Owing to the dorsoventrally narrow upper beak, the caudal nasal bar is more obliquely oriented than in many extant schizorhinal Charadriiformes. The mandible exhibits a long and slitlike fenestra rostralis mandibulae and a small, subcircular fenestra caudalis mandibulae; the caudal end seems to lack the distinct, dorsally directed process that is characteristic for many crown group charadriiforms (Fig. 2). The left quadrate is visible in caudal view, the right one in lateral view (Fig. 2). Taxonomically significant details of the bone, however, cannot be discerned. Although the fossil preserves elements of the hyoid apparatus (Fig. 2A), no ossified tracheal rings are visible. The cervical vertebrae (Fig. 3E) are of average proportions and neither very long nor very short, with deep lacunae interzygapophysiales. The number of praesacral vertebrae cannot be determined and no features of phylogenetic significance are visible. The ventral surface of the cranial end of the synsacrum bears a pair of shallow, lateral depressions (Fig. 3F), but whether these indicate pleurocoelous thoracic vertebrae (a characteristic feature of charadriiform birds, in which the thoracic vertebrae bear deep lateral depressions) cannot be said. Few details of the fragmentary wing and pectoral girdle elements are discernible. Of both humeri, only the distal portions are preserved as bone substance. The outline of the proximal end of the left humerus is, however, traced by a resin cast of the void left by the bone in the original matrix (like most Messel fossils, the specimen was prepared with the resin transfer method) and allows the recognition of a fairly large tuberculum dorsale (Fig. 3A). The distal end of the left humerus bears a small processus supracondylaris dorsalis, whose tip is broken (Fig. 3A). A processus supracondylaris dorsalis characterizes charadriiform birds, but in SMNK.PAL 8683 the process is much smaller than in most extant charadriiform taxa (in Jacanidae, this process is, however, likewise only weakly developed; Fig. 3B). On the right humerus, a well-developed processus flexorius is visible (Fig. 3C). Both ulnae lack the distal portions, with the distal end of the left ulna having been on a missing part of the slab, whereas the distal right ulna appears to exhibit a perimortem fracture. Only the right carpometacarpus is preserved and lacks its proximal portion. The bone is fairly long, with a narrow
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spatium intermetacarpale and a long symphysis metacarpalis distalis (Fig. 3D). The proximal end of the os metacarpale minus forms a small ventral projection. The phalanx proximalis digiti majoris is of average proportions. Except for a portion of the right scapula, elements of the pectoral girdle are not visible, and remains of the wing and tail feathers are likewise not preserved. Overall and as far as comparisons are possible, the wing bones correspond well with those of Songzia, although critical bone sections, such as the distal end of the humerus, are not well preserved in the Songzia fossils (Wang et al., 2012). The leg bones are more complete, but the poor preservation of the specimen impedes the recognition of osteological details. The crista cnemialis cranialis of the tibiotarsus (Fig. 3G) is only moderately prominent and less developed than in most charadriiform birds; the condylus medialis (Fig. 4A) is fairly large and its proximodistal length exceeds the minimum mediolateral width of the tibiotarsus shaft. The tarsometatarsus (Fig. 4) is long and slender. The hypotarsus of the right tarsometatarsus is visible in medial (SMNK.PAL 8683b) and lateral (SMNK.PAL 8683a) view. It is proximodistally short, with moderate plantar prominence, and has a similar shape to the hypotarsus of charadriiform birds. The foramen vasculare distale on the distal end of the bone is very large (Fig. 4B). Details of the tarsometatarsal trochleae cannot be seen. The tarsometatarsus of Songzia has similar overall proportions to that of Vanolimicola, but the size of the foramen vasculare distale is not clearly visible in the known specimens. The toes exhibit a characteristic morphology. Most notably, the hallux is unusually long, reaching almost one third of the length of the tarsometatarsus, and its first phalanx is markedly curved. The third toe measures slightly less than the length of the tarsometatarsus. The fourth phalanx of the fourth toe has about the same length as the third phalanx, which characterizes Charadriiformes and a few other extant avian groups (e.g., Otididae; Hesse, 1988). The ungual phalanges are relatively long and straight.
4. Discussion The holotype of Vanolimicola longihallucis, gen. et sp. nov. is fragmentary and not well preserved, but the comparatively long legs and the “limicoline” beak prompt comparisons with Charadriiformes and suggest that V. longihallucis was foraging in the shore area of the Messel lake. The only previous record of a putative charadriiform bird from Messel was described by Mayr (2000). This fossil stems from an unnamed species and consists of wing and pectoral girdle elements, so that only few meaningful comparisons with the V. longihallucis holotype are possible. With a carpometacarpus length of 17.2 mm, the specimen is, however, much larger than V. longihallucis. The new species agrees with Charadriiformes in the proportions of the phalanges of the fourth toe, with the fourth phalanx being of subequal length to the third (Hesse, 1988). In birds, the fourth phalanx of the fourth toe is usually longer than the third, but in some taxa, the proportions of this phalanx are variable, which diminishes the phylogenetic significance of the character (e.g., whereas the fourth phalanx of the fourth toe is distinctly longer than the
processus supracondylaris dorsalis; rad, radius; smd, symphysis metacarpalis distalis; syn, synsacrum; tbd, tuberculum dorsale; tbt, tibiotarsus; tho, thoracic vertebra; uln, ulna. Fossils were coated with ammonium chloride. Scale bars equal 5 mm. Détails ostéologiques de Vanolimicola longihallucis, gen. et sp. nov. A : humérus gauche en vue caudale (SMNK.PAL 8683b) ; noter que toute la moitié proximale de l’os est seulement préservée sous forme de coulée de résine. B : humérus gauche (vue caudale) de Jacana noir, Jacana jacana (Jacanidae). C : humérus droit en vue caudale (SMNK.PAL 8683b). D : portion distale (main) de l’aile droite en vue ventrale (SMNK.PAL 8683b). E :vertèbres cervicales (SMNK.PAL 8683b). F : région pelvienne en vue ventrale (SMNK.PAL 8683a). G : extrémité proximale du tibiotarsus droit (SMNK.PAL 8683a). Abréviations : ccc, crista cnemialis cranialis ; fem, fémur ; dep, dépression à l’extrémité crânienne du synsacrum ; flx, processus flexorius ; fvd, foramen vasculare distale ; ocu, os carpi ulnare ; pdm, phalanx proximalis digiti majoris ; mtI, os metatarsale I ; prj, projection ventrale à l’extrémité proximale de l’os metacarpale minus ; psd, processus supracondylaris dorsalis ; rad, radius ; smd, symphysis metacarpalis distalis ; syn, synsacrum ; tbd, tuberculum dorsale ; tbt, tibiotarsus ; tho, vertèbre thoracique ; uln, ulna. Les fossiles ont été recouverts de chlorure d’ammonium. Les échelles représentent 5 mm.
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Fig. 4. Feet of Vanolimicola longihallucis, gen. et sp. nov. A: left foot in dorsal view (SMNK.PAL 8683a). B: detail of distal end of left foot (SMNK.PAL 8683a). C, D: right foot in lateral (SMNK.PAL 8683a) and medial (SMNK.PAL 8683b) view. E: left tarsometatarsus of the Wattled Jacana, Jacana jacana (Jacanidae). F: left foot of Songzia acutunguis (Songziidae) from the Early Eocene of China (IVPP 18188). G: right foot (dorsal view) of the African Jacana, Actophilornis africanus (Jacanidae; the ungual phalanx of the third toe is broken and lacks its tip). Abbreviations: cdm, condylus medialis; fvd, foramen vasculare distale. The toes are numbered. Fossils in A–D were coated with ammonium chloride. Scale bars equal 5 mm. Pieds de Vanolimicola longihallucis, gen. et sp. nov. A : pied gauche en vue dorsale (SMNK.PAL 8683a). B : détail de l’extrémité distale du pied gauche (SMNK.PAL 8683a). C, D : pied droit en vue latérale (SMNK.PAL 8683a) et médiane (SMNK.PAL 8683b). E : tarsometatarsus gauche de Jacana noir, Jacana jacana (Jacanidae). F : pied gauche de Songzia acutunguis (Songziidae) de l’Eocène Inférieur de Chine (IVPP 18188). G: pied droit (vue dorsale) de Jacana à poitrine dorée, Actophilornis africanus (Jacanidae, la phalange unguéale du troisième orteil est cassée et son extrémité distale manque). Abréviations : cdm, condylus medialis ; fvd, foramen vasculare distale. Les orteils sont numérotés. Les fossiles en A–D ont été recouverts de chlorure d’ammonium. Les échelles représentent 5 mm.
third in most Rallidae, both phalanges are of subequal length in Himantornis haematopus and Canirallus oculeus). Concerning the unusually long hallux, V. longihallucis clearly differs from most extant Charadriiformes, in which the hind toe is short to very short. A very long hallux is only found in Jacanidae, with which V. longihallucis also agrees in the large foramen vasculare distale of the tarsometatarsus, which is, however, even larger in the Jacanidae. As in Vanolimicola and unlike in most other charadriiform birds, the processus supracondylaris dorsalis of the humerus is only weakly developed in extant Jacanidae. In contrast
to Vanolimicola, however, jacanas also have very long fore toes with extremely elongated ungual phalanges, which enable these birds to walk on floating vegetation (Fig. 4G). The legs of jacanas are furthermore proportionally longer than those of Vanolimicola, with the tibiotarsus distinctly exceeding the skull in length. All of these differences may well be due to the possibility that Vanolimicola is a very early stem group representative of jacanids, in which case it would be the oldest fossil record of the group, with the earliest definitive Jacanidae being from the Late Eocene of Egypt (Rasmussen et al., 1987; Mayr, 2016b).
Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001
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Currently, however, an assignment of V. longihallucis to Jacanidae is not strongly based and compared with other Eocene birds, the new species also resembles the taxon Songzia from the Bumbanian of China (Hou, 1990; Wang et al., 2012). Like Vanolimicola, Songzia has a very long hallux, although the three fore toes of the Chinese taxon are proportionally longer than those of Vanolimicola. The nostrils of S. acutunguis appear to have been holorhinal, but their caudal ends are not well visible in the two known specimens. Songzia has proportionally shorter wings than Jacanidae and other charadriiform birds, and unlike in Charadriiformes the ulna does not exceed the humerus in length. In fact, the relative length of the ulna is a feature that readily distinguishes Jacanidae and all other extant representatives of Charadriiformes from the Ralloidea. Unfortunately, humerus and ulna are very fragmentary in the V. longihallucis holotype, and their relative lengths cannot be assessed. Future specimens with well preserved wing bones are therefore needed to further evaluate the affinities between V. longihallucis and either Jacanidae or Songziidae. With an age of 55.8–54.8 million years (Ni et al., 2013), the Songzia fossils are about 7 million years older than V. longihallucis from Messel. It should finally be mentioned that there exists an undescribed fossil from the Green River Formation, which was figured by Grande (2013: Fig. 143A, top right, FMNH PA 728) and shows some overall similarity to V. longihallucis. This North American fossil likewise features long nostrils and a long hallux, but with a skull length of 44 mm (Grande, 2013), it is from a larger species. Unlike in V. longihallucis, the fourth phalanx of the fourth toe is furthermore longer than the third, and the nostrils have a rounded caudal margin and are therefore holorhinal. Grande (2013: Fig. 143A, bottom right) referred a second specimen from the Green River Formation (FMNH PA 756) to the same undescribed species, but detailed studies of these fossils are required for an assessment of possible affinities to V. longihallucis. Disclosure of interest
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Acknowledgements I thank Eberhard Frey (SMNK) for the loan of the fossil and Sven Tränkner for photographs of the Messel specimen; the Songzia photos were taken by Min Wang (IVPP). Lance Grande (FMNH) is thanked for a photo of the Vanolimicola-like fossil from the Green River Formation. Comments from Vanesa De Pietri and an anonymous reviewer improved the manuscript. References Grande, L., 2013. The lost world of fossil lake. Snapshots from deep time. University of Chicago Press, Chicago. Hesse, A., 1988. Taxonomie der Ordnung Gruiformes (Aves) nach osteologischen morphologischen Kriterien unter besonderer Berücksichtigung der Messelornithidae Hesse, 1988. Courier Forschungsinstitut Senckenberg 107, 235–247. Hou, L.H., 1990. An Eocene bird from Songzi. Hubei province. Vertebrata PalAsiatica 28, 34–42. Lenz, O.K., Wilde, V., Mertz, D.F., Riegel, W., 2015. New palynology-based astronomical and revised 40Ar/39Ar ages for the Eocene maar lake of Messel (Germany). International Journal of Earth Sciences 104, 873–889. Mayr, G., 2000. Charadriiform birds from the early Oligocene of Céreste (France) and the Middle Eocene of Messel (Hessen Germany). Geobios 33, 625–636. Mayr, G., 2009. Paleogene fossil birds. Springer, Heidelberg. Mayr, G., 2016a. Fragmentary but distinctive: three new avian species from the early Eocene of Messel, with the earliest record of medullary bone in a Cenozoic bird. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 279, 273–286. Mayr, G., 2016b. Avian evolution: the fossil record of birds and its paleobiological significance. Wiley-Blackwell, Chichester. Mayr, G., in press a. The early Eocene birds of the Messel fossil site: a 48 million-yearold bird community adds a temporal perspective to the evolution of tropical avifaunas. Biological Reviews. 10.1111/brv.12274. Mayr, G., in press b. New species of Primozygodactylus from Messel and the ecomorphology and evolutionary significance of early Eocene zygodactylid birds (Aves, Zygodactylidae). Historical Biology.10.1080/08912963.2016.1261135. Ni, X., Gebo, D.L., Dagosto, M., Meng, J., Tafforeau, P., Flynn, J.J., Beard, K.C., 2013. The oldest known primate skeleton and early haplorhine evolution. Nature 498, 60–64. Rasmussen, D.T., Olson, S.L., Simons, E.L., 1987. Fossil birds from the Oligocene Jebel Qatrani Formation, Fayum Province. Egypt. Smithsonian Contributions to Paleobiology 62, 1–20. Wang, M., Mayr, G., Zhang, J., Zhou, Z., 2012. Two new skeletons of the enigmatic, rail-like avian taxon Songzia Hou, 1990 (Songziidae) from the early Eocene of China. Alcheringa 36, 487–499.
The author declares that he has no competing interest.
Please cite this article in press as: Mayr, G., A small, “wader-like” bird from the Early Eocene of Messel (Germany). Annales de Paléontologie (2017), http://dx.doi.org/10.1016/j.annpal.2017.01.001