Eocene Lagomorpha (Mammalia) of Asia: 2. Strenulagus and Gobiolagus (Strenulagidae)

Two species of early lagomorph, Strenulagus solaris sp. nov. (Monogolia, Khaychin-Ula 2 and 3 localities, Middle Eocene) and Gobiolagus hekkeri (Kyrgyzstan, Andarak 2 locality, terminal Lower Eocene), are described. A revision of Romanolagus hekkeri Shevyreva from the Andarak 2 locality has shown that it belongs to the genus Gobiolagus; consequently, the monotypic genus Romanolagus Shevyreva, 1995 is a junior synonym of Gobiolagus Burke, 1941. The diagnoses and species compositions of the genera Strenulagus and Gobiolagus are revised. Zaissanolagus gromovi Erbajeva from the Lower Oligocene of eastern Kazakhstan is shown to be the latest representative of the genus Gobiolagus and the family Strenulagidae.     

First record of Entelodontidae (Mammalia,Artiodactyla) from the late Eocene of Southeast Asia

We describe two entelodontid upper premolars that were recovered from the late Eocene of the Krabi coal mine in southern Thailand. The size and morphology of the material suggest that it can be referred to Entelodon aff. E. gobiensis, a species known from the late Eocene to the early Oligocene of northern Asia and southern China. The Thai material documents for the first time the southernmost occurrence of entelodontids in Asia during the Paleogene and also suggests that Eocene Southeast Asian mammal localities might potentially yield further entelodontid remains mostly associated with selenodont ungulates.     

Phylogeny and systematic revision of Eocene Cricetidae (Rodentia,Mammalia) from Central and East Asia: on the origin of cricetid rodents

The origin of the Cricetidae and the relationships among earliest species from Central and East Asia are still disputed. The taxonomic status of some Eocene cricetid taxa is also doubtful. A parsimony analysis based on 65 cranial and dental characters and including 22 early Myomorpha was performed to elucidate these issues. As a result, the North American Elymys, known as the first Myodonta, belongs to dipodoid rodents, although it shares a suite of characters with the first cricetids. This implies that the split between dipodoids and muroids occurred in North America during the early middle Eocene, as previously supposed. The disputed Simimys and Nonomys could constitute an early dipodoid radiation. It appears that the earliest offshoot of the cricetid clade is the Asian genus Palasiomys. This taxon has a more advanced cricetid plan than contemporaneous dipodoids. The genus Raricricetodon no longer exists here because it is polyphyletic; the species are included in Palasiomys (P. minor, P. trapezius) and Pappocricetodon (P. zhongtiaensis). The genus Pappocricetodon displays a complete cricetid plan associated with both the loss of P⁴ and the development of an anterocone on M¹. The disputed genera Eocricetodon and Oxynocricetodon characterize the beginning of the Oligocene radiations of Eucricetodontinae throughout the Holarctic continents.     

Early Eocene lagomorph (Mammalia) from Western India and the early diversification of Lagomorpha

We report the oldest known record of Lagomorpha, based on distinctive, small ankle bones (calcaneus and talus) from Early Eocene deposits (Middle Ypresian equivalent, ca 53 Myr ago) of Gujarat, west-central India. The fossils predate the oldest previously known crown lagomorphs by several million years and extend the record of lagomorphs on the Indian subcontinent by 35 Myr. The bones show a mosaic of derived cursorial adaptations found in gracile Leporidae (rabbits and hares) and primitive traits characteristic of extant Ochotonidae (pikas) and more robust leporids. Together with gracile and robust calcanei from the Middle Eocene of Shanghuang, China, also reported here, the Indian fossils suggest that diversification within crown Lagomorpha and possibly divergence of the family Leporidae were already underway in the Early Eocene.     

Zhailimeryx, A New Lophiomerycid Artiodactyl (Mammalia) from the Late Middle Eocene of Central China and the Early Evolution of Ruminants

A new genus and species of primitive selenodont artiodactyl, Zhailimeryx jingweni, occurs in the late middle Eocene Zhaili Member of the Heti Formation, Yuanqu Basin, Shanxi Province, China. A phylogenetic analysis of dental characters suggests that Zhailimeryx is closely related to Lophiomeryx and other lophiomerycid ruminants of Asia and Europe. Zhailimeryx and other Eocene records of Lophiomerycidae from Asia support an Asian origin for this family, followed by dispersal into Europe both before and after the Grande Coupure. Morphological evidence from Zhailimeryx suggests that ruminant artiodactyls had already undergone substantial diversification prior to the late middle Eocene, and it reopens the issue of whether the higher taxa Tragulina and Pecora are valid expressions of ruminant phylogeny.     

Taxonomy of Allobethylus Kieffer (Hymenoptera: Bethylidae) from southeastern Asia

Two new species of Allobethylus Kieffer, 1905 are described and illustrated. Allobethylus korystus sp. nov. from Thailand is characterized as having a mandible with four apical teeth, a clypeus with a trapezoidal frontal profile and a pronotal declivity with a conspicuous crest. The last two traits are new characteristics to the genus. Allobethylus lamprus sp. nov. from Myanmar is characterized as having a mandible with three apical teeth, a clypeus with a triangular frontal profile and a bidentate median lobe. Additionally, A. multicolor Kieffer is recorded for the first time from Thailand. An updated world key to the species of genus is also provided.     

Paratritemnodon indicus (Creodonta: Mammalia) from the early Middle Eocene Subathu Formation,NW Himalaya,India, and the Kalakot mammalian community structure

A complete post-incisor upper dentition and a left mandible with P/3-M/3 of the proviverrine hyaenodontid (Creodonta: Mammalia)Paratritemnodon indicus, which was hitherto known by heavily worn P/3-M/3, are described from the uppermost Subathu Formation (Middle Eocene) of the Kalakot-Metka-Mohgala area, Rajauri District, Jammu and Kashmir.P. indicus is most closely related to the North American Early Eocene proviverrine,Tritemnodon; its relationships withProdissopsalis from the Middle Eocene of Europe andPropterodon from the Middle to Late Eocene of China are also close. In the Kalakot Eocene vertebrate community of the Subathu vertebrate bioprovince,P. indicus is the only land dwelling carnivorous mammal against more than 20 species of herbivorous mammals, a majority of which are larger than it. This is viewed as an imbalance in trie community and it reflects an immaturity of the ecosystem supporting the fauna. The scarcity of carnivore remains in the Kalakot mammalian fauna is not an artifact.     

New material of Diacodexis (Mammalia,Artiodactyla) from the early Eocene of Southern Europe

Diacodexeidae are the first representatives of Artiodactyla in the fossil record. Their first occurrence is at the very base of the Ypresian (earliest Eocene, 56.0 Ma) with Diacodexis, a genus well diversified during the early Eocene in Europe, especially during the MP7–MP8 + 9 interval. However, most of European species are documented by scarce material, retrieved from single localities. In this work, we describe new Diacodexis material from ～MP7 and ～MP8 + 9 localities of Southern Europe, including material of D. antunesi from Silveirinha, considered as the most primitive European Diacodexis species, and material from three localities from Southern France (Fordones, Palette, and La Borie). The new material documents Diacodexis premolar morphology and deciduous dentition which bear potentially important phylogenetic information, as well as astragali, including a specimen from Silveirinha that constitutes the earliest occurrence of an astragalus of the genus Diacodexis in the European fossil record. Investigation of the enamel microstructure reveals that early European species had a simple enamel pattern with one-layered Schmelzmuster composed of ‘basic’ radial enamel only, instead of the two-layered Schmelzmuster (thin radial enamel + thick layer of Hunter-Schreger bands) observed on North American species and so far considered to represent the primitive condition within Artiodactyla. In accordance with previous studies, our observations highlight that Diacodexis gigasei from Belgium is morphologically closer to the North American species D. ilicis than to D. antunesi from Portugal. The latter species, together with D. aff. antunesi from Fordones, appears to be morphologically closer to the Asiatic taxa D. indicus and D. pakistanensis. Finally, we found numerous similarities between D. cf. gigasei from Palette and D. gigasei, a result that challenges the intra-European provincialism that characterizes the earliest Ypresian. Diacodexis gigasei could be one of the rare species shared by the northwestern and southwestern European bioprovinces.     

The paroxyclaenidae (Mammalia) and a new form from the early Eocene of Palette,France

A new genus and species of the Paroxyclaenidae is described,Merialus martinae, and the family is reviewed and divided into two subfamilies, the Paroxyclaeninae and the Merialinae, new. The two species ofDyspterna are attributed to two genera, of whichEuhookeria is new; Dyspterninae Kretzoi, 1943, is resurrected to includeDyspterna woodi, Cryptopithecus andKochictis; the subfamily is referred to the Pantolestidae.Vulpavoides is considered valid and includes“Russellites” simplicidens;V. vanvaleni n. sp. is described from Bouxwiller.Kiinkerishella andDulcidon are discussed, as are possible relationships between the Ptolemaiidae and the Merialine paroxyclaenids.     

A ctenodactylid rodent (Mammalia: Rodentia) from the Middle Miocene of Chios Island (Greece)

Field work carried out in 1991 and 1993 at the Middle Miocene locality of Thymiana (Chios Island, Greece), produced much rodent material including a number of ctenodactylid dental specimens. They represent a single taxon whose upper and lower cheek tooth morphology clearly differs from Prosayimys flynni and all Sayimys species known so far, except for Sayimys intermedius. The ctenodactylid teeth from the Middle Miocene of Chios are identified as pertaining to the latter species, despite minor differences from the Pakistani and Saudi Arabian representatives of S. intermedius.     

新疆准噶尔盆地北缘中中新世早期的原圆齿鼠(Promylagaulinae,Mylagaulidae)(英文)

<正>1988年吴文裕描述了产自新疆准噶尔盆地北缘铁尔斯哈巴合地点哈拉玛盖组下部层位的一枚圆齿鼠的P4,定名为Sinomylagaulus halamagaiensis。1997年中国科学院古脊椎动物与古人类研究所新疆考察队又在铁尔斯哈巴合的哈拉玛盖组下部层位中采集到两枚p4。1988年的研究工作仅依据一枚上前臼齿(P4),标本的稀缺决定了当时研究成果的局限性。新材料无疑为认识新疆的圆齿鼠类提供了新的信息     

New acrodont lizards (Lacertilia) from the Middle Eocene of southern Mongolia

The problematic lizard family Changjiangosauridae, representatives of which inhabited Asia in the Early Paleogene, is discussed. Six new species of this group, including Acrodontopsis robustus gen. et sp. nov., Agamimus gracilis gen. et sp. nov., Graminisaurus interruptus gen. et sp. nov., Khaichinsaurus reshetovi gen. et sp. nov., Lavatisaurus elegans gen. et sp. nov., and Lentisaurus giganteus gen. et sp. nov., from the Middle Eocene of the Khaichin Uul 2 locality (southern Gobi, Mongolia) are described. It is shown that Changjiangosauridae are probably related to the Late Cretaceous Isodontosauridae and recent Uromastycidae; independent development of a number of dental features in different lineages of Acrodonta (Iguania) is corroborated.     

Sinopaninae and Arfianinae (Hyaenodontida,Mammalia) from the Early Eocene of Europe and Asia; evidence for dispersal in Laurasia around the Paleocene/Eocene boundary and for an unnoticed faunal turnover in Europe

Hyaenodontida are represented in Europe by three subfamilies: Proviverrinae, Arfianinae and Sinopaninae. Here, we review all the specimens of Arfianinae and Sinopaninae known to date in Europe and Asia. A new Galecyon species is erected: Galecyon gallus nov. sp. We discuss the taxonomic position of the two Asian hyaenodontidans Anthracoxyaena palustris and Arfia langebadreae; the genus Anthracoxyaena is synonymized with Arfia. The analysis of the European and Asian arfianines and sinopanines provides new data concerning the dispersals and faunal events that occurred during the Early Eocene in Laurasia. The Arfianinae and Sinopaninae appeared in Europe around the Paleocene/Eocene boundary (reference-level MP7). The sinopanines are widespread in Europe; they are known in Dormaal (Belgium, reference-locality of the level MP7), Rians, Soissons, Pourcy, Try, Le Quesnoy (France), and Abbey Wood (England). The analysis of the paleogeographic distribution of all Oxyaenodonta and Hyaenodontida at and after the MP7 supports the existence of two European provinces: the North Province and Mesogean Province. We show that the Arfianinae and Sinopaninae rapidly disappeared from Europe; they are unknown in Avenay (reference-locality of the level MP8+9) and younger localities. Their disappearance from Europe is synchronous with that of the Oxyaenodonta. These observations support the existence of a faunal turnover, which occurred between the reference-levels MP7 (Dormaal) and MP8+9 (Avenay). The hypothesis of a dispersal from Europe to North America during the Paleocene-Eocene transition for the Arfianinae and Sinopaninae is supported. Moreover, the study of Arfianinae supports a dispersal from Europe to Asia around the P/E boundary, followed by a short period of endemic evolution. However, our study does not support a close relationship between Arfia and the “Arfia-like South Asian Proviverrinae” (Kyawdawia, Indohyaenodon, Paratritemnodon and Yarshea).     

A new Chalicothere from the Pondaung Formation (late Middle Eocene of Myanmar)

The 2002 field work campaign of the joint Myanmar–French Expedition has resulted in the discovery of new material particularly in the Bahin area (Pondaung Formation, Middle–Upper Eocene, Myanmar). The Nyaung Pin Le outcrop has yielded, among other fossil mammals, a maxillary of a primitive chalicothere, the first ever discovered in the southeastern Asia Palaeogene, which is assigned to the Eomoropidae, Eomoropus pawnyunti nov. sp. This form is distinguished from the other representatives of the family by its small size, its brachyodonty and the few derived shape of the molar ectolophs, nevertheless provided with low mesostyles. To cite this article: J.-A. Remy et al., C. R. Palevol 4 (2005).     

A New Eocene Dasypodid with Caniniforms (Mammalia,Xenarthra, Cingulata) from Northwest Argentina

The aim of this work is to present a new genus and species of Dasypodidae from the Lumbrera Formation (“lower Lumbrera”), early-middle Eocene of Salta Province, northwest Argentina. The new taxon, documented by one specimen, consists of an incomplete skull and jaw with teeth housed in their alveoli, postcranial remains, and isolated osteoderms. Lumbreratherium oblitum, gen. et sp. nov., is characterized by heterodont dentition, with a caniniform as the first tooth, diastema between caniniform and first molariform, teeth with closed roots, and a peculiar morphology of the osteoderms. A phylogenetic analysis indicates that Lumbreratherium oblitum, gen. et sp. nov., and Pucatherium parvum belong to a monophyletic clade in a basal position within the Cingulata. The singularity of the morphological characteristics of these Paleogene armadillos of northwest Argentina reinforces the hypothesis of an intertropical origin of mammal clades different from those of the Paleogene in more austral regions of Argentina.     

Taxonomy and phylogeny of theParanourosorex lineage,Neogene of Eurasia (Mammalia: Soricidae: Anourosoricini)

Paranourosorex remains from 14 Miocene and Pliocene localities in Inner Mongolia (China) and SW Siberia (Russia, Kazakhstan) are referred to a detailed biochronological sequence. The fossils are considered to represent a single evolutionary lineage which ranges in time from late middle Turolian (MN 12) through late early Ruscinian (MN 14). The lineage is subdivided into 5 species, including the previously describedP. gigas Rzebik-Kowalska 1975 from Poland.Neomys inexspectatus Schlosser 1924 is assigned toParanourosorex, andP. seletiensis n.sp. is described as new. All taxa are diagnosed. Evolutionary changes within theParanourosorex lineage over a period of about 1.5 my are discussed. Intratribal comparisons suggest 3 anourosoricine clades during the Mio/Pliocene of Eurasia, consisting of 1)Crusafontina, 2) Paranourosorex, and 3)Anourosorex andAmblycoptus.