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1. chinaXiv:202004.00003 [pdf]

A new species of Amynodontopsis (Perissodactyla:?Amynodontidae) from the Middle Eocene of Jiyuan,?Henan, China

WANG Xiao-Yang; WANG Yuan-Qing; ZHANG Rui; ZHANG Zhong-Hui; ?LIU Xiao-Ling; REN Li-Ping
Subjects: Biology >> Zoology

An adult amynodont skull, collected from the Middle Eocene Niezhuang Formation of Jiyuan Basin (Henan, China), is recognized as a new species Amynodontopsis jiyuanensis sp. nov. The specimen possesses the typical features of the genus Amynodontopsis, such as a dolichocephalic skull with elevated roof, premaxilla-nasal contact, large preorbital fossa extending posteriorly medial to the orbit, inner surface of anterior orbital bar concave in continuation with the preorbital fossa, antecrochet usually presented on M1, and metastyle of M3 strongly deflected labially. A. jiyuanensis is diagnosed by a combination of the following characters: long nasals, nasal process of premaxilla extending far back laterally below the nasal and excluding the maxilla from the border of external nares, nasal notch above the post-canine diastema, more transverse and proportionally longer protoloph and metaloph on upper molars. Comparison with known species of Amynodontopsis indicates that it is the most primitive one in the genus, due to the possession of primitive characters. Associated fossil mammals support a correlation of the strata bearing A. jiyuanensis with the Shara Murun Formation of the Erlian Basin, Nei Mongol, China, namely the Middle Eocene Sharamurunian Asian Land Mammal Age (ALMA), prior to all other known Amynodontopsis species. The earlier geologic age and primitive morphological features of A. jiyuanensis suggest that Amynodontopsis has an Asian origin in the Middle Eocene and later immigrated into North America.

submitted time 2020-03-31 From cooperative journals:《古脊椎动物学报》 Hits6705Downloads1327 Comment 0

2. chinaXiv:201910.00060 [pdf]

Reinvestigation of the scaling law of the windblown sand launch velocity with a wind tunnel experiment

ZHANG Yang1; LI Min; WANG Yuan; YANG Bin
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology

Windblown sand transport is a leading factor in the geophysical evolution of arid and semi-arid regions. The evolution speed is usually indicated by the sand transport rate that is a function of launch velocity of sand particle, which has been investigated by the experimental measurement and numerical simulation. However, the obtained results in literatures are inconsistent. Some researchers have discovered a relation between average launch velocity and wind shear velocity, while some other researchers have suggested that average launch velocity is independent of wind shear velocity. The inconsistence of launch velocity leads to a controversy in the scaling law of the sand transport rate in the windblown case. On the contrary, in subaqueous case, the scaling law of the sand transport rate has been widely accepted as a cubic function of fluid shear velocity. In order to explain the debates surrounding the windblown case and the difference between windblown and subaquatic cases, this study reinvestigates the scaling law of the vertical launch velocity of windblown transported sand particles by using a dimensional analysis in consideration of the compatibility of the characteristic time of sand particle motion and that of air flow. Then a wind tunnel experiment is conducted to confirm the revisited scaling law, where the sand particle motion pictures are recorded by a high-speed camera and then the launch velocity is solved by the particle tracking velocimetry. By incorporating the results of dimensional analysis and wind tunnel experiment, it can be concluded that, the ratio of saltons number to reptons number determines the scaling law of sand particle launch velocity and that of sand transport rate, and using this ratio is able to explain the discrepancies among the classical models of steady sand transport. Moreover, the resulting scaling law can explain the sand sieving phenomenon: a greater fraction of large grains is observed as the distance to the wind tunnel entrance becomes larger.

submitted time 2019-10-26 From cooperative journals:《Journal of Arid Land》 Hits1423Downloads953 Comment 0

3. chinaXiv:201908.00120 [pdf]

New gobiconodontid (Eutriconodonta, Mammalia) from?the Lower Cretaceous Shahai and Fuxin formations,?Liaoning, China

KUSUHASHI Nao; WANG Yuan-Qing; ?LI Chuan-Kui; JIN Xun
Subjects: Biology >> Zoology

Eutriconodontans are one of the key members of mammals to our understanding of the evolution and transition of mammalian fauna in Asia during the Cretaceous. Two gobiconodontid?and two triconodontid species have previously been reported from the upper Lower Cretaceous?Shahai and Fuxin formations. Here we describe two additional eutriconodontans from the?formations, Fuxinoconodon changi gen. et sp. nov. and ?Gobiconodontidae gen. et sp. indet.?This new species is attributed to the Gobiconodontidae, characterized by having an enlarged?first lower incisor, reduction in the number of incisors and premolariforms, proportionally large?cusps b and c being well distant from cusp a on the molariforms, presence of a labial cingulid,?and a unique mixed combination of molariform characters seen on either the first or the second,?but not both, generations of molariforms in Gobiconodon. Together with the four known species,?eutriconodontans remained diverse to some extent in the late Early Cretaceous in Asia, although?their family-level and generic level diversity appears to have been already reduced at that time.

submitted time 2019-08-26 From cooperative journals:《古脊椎动物学报》 Hits9035Downloads1173 Comment 0

4. chinaXiv:201908.00119 [pdf]

New gobiconodontid (Eutriconodonta, Mammalia) from?the Lower Cretaceous Shahai and Fuxin formations,?Liaoning, China

KUSUHASHI Nao; WANG Yuan-Qing; ?LI Chuan-Kui; JIN Xun
Subjects: Biology >> Zoology

Eutriconodontans are one of the key members of mammals to our understanding of the evolution and transition of mammalian fauna in Asia during the Cretaceous. Two gobiconodontid?and two triconodontid species have previously been reported from the upper Lower Cretaceous?Shahai and Fuxin formations. Here we describe two additional eutriconodontans from the?formations, Fuxinoconodon changi gen. et sp. nov. and ?Gobiconodontidae gen. et sp. indet.?This new species is attributed to the Gobiconodontidae, characterized by having an enlarged?first lower incisor, reduction in the number of incisors and premolariforms, proportionally large?cusps b and c being well distant from cusp a on the molariforms, presence of a labial cingulid,?and a unique mixed combination of molariform characters seen on either the first or the second,?but not both, generations of molariforms in Gobiconodon. Together with the four known species,?eutriconodontans remained diverse to some extent in the late Early Cretaceous in Asia, although?their family-level and generic level diversity appears to have been already reduced at that time.

submitted time 2019-08-26 From cooperative journals:《古脊椎动物学报》 Hits8882Downloads1210 Comment 0

5. chinaXiv:201804.01251 [pdf]

Fossil gibbons (Mammalia, Hylobatidae) from the Pleistocene of Chongzuo, Guangxi Zhuang Autonomous Region, China

ZHANG Ying-Qi; JIN Chang-Zhu; WANG Yuan; Alejandra ORTIZ; HE Kai; Terry HARRISON
Subjects: Geosciences >> Geology

Recent fieldwork at Pleistocene cave sites in the Chongzuo area in Guangxi Zhuang Autonomous Region has yielded 33 isolated teeth of fossil hylobatids. Comparisons indicate that the teeth can all be referred to a single species of Nomascus, but the material is insufficient to assign it to a particular species. The molars are slightly larger on average than those of extant species of Nomascus, but unlike contemporary great apes from the Pleistocene of southern China, the hylobatids do not seem to have undergone a change in dental size through time. Nomascus is not present in the Chongzuo area today, but historical records indicate that the genus may have been widely distributed across southern China in the recent past.

submitted time 2018-04-04 From cooperative journals:《古脊椎动物学报》 Hits5821Downloads1626 Comment 0

6. chinaXiv:201802.00746 [pdf]

Reappraisal of Endotherium niinomii Shikama, 1947, a eutherian mammal from the Lower Cretaceous Fuxin Formation, Fuxin-Jinzhou Basin, Liaoning, China

WANG Yuan-Qing; KUSUHASHI Nao; JIN Xun; LI Chuan-Kui; SETOGUCHI Takeshi; GAO Chun-Ling; LIU Jin-Yuan
Subjects: Geosciences >> Geology

Reinvestigation of the Early Cretaceous eutherian mammal Endotherium niinomii Shikama, 1947, based on the impressions of the type specimen, casts made from the impressions, and the original description, indicates that E. niinomii is characterized by the following characters: decrease in size from the m1 to the m3; a moderate height difference between the trigonid and talonid of lower molars; blunt lower molar cusps; the protoconid being the largest among the trigonid cusps; the paraconid being as tall as the metaconid; the p3 not being obviously reduced; and possible possession of five lower premolars. These characteristics clearly distinguish E. niinomii from other known Cretaceous eutherians, and support its taxonomic identity as a valid taxon.

submitted time 2018-02-26 From cooperative journals:《古脊椎动物学报》 Hits5809Downloads1768 Comment 0

7. chinaXiv:201801.00584 [pdf]

Postcranial morphology of Middle Eocene deperetellid Teleolophus (Perissodactyla, Tapiroidea) from Shara Murun region of the Erlian Basin, Nei Mongol, China

BAI Bin; WANG Yuan-Qing; MENG Jin
Subjects: Geosciences >> Geology

Deperetellidae are a group of common, endemic Asian Middle Eocene tapiroids. Although five genera within the family have been named, most of them were represented by fragmentary maxillae and mandibles except for some skeletal material of Deperetella. Based exclusively on dental characters, different authors have proposed affinities of deperetellids with, for instance, helaletid Colodon, lophialetids, or rhodopagids. Here we described the partial postcranial skeleton of Teleolophus medius? recently discovered at Wulanhuxiu (=Ulan Shireh) of the Erlian Basin, China, and compared the postcranial skeletons of Teleolophus with those of Lophialetes, Deperetella, Heptodon, Helaletes, and Colodon. The postcranial skeleton of Teleolophus shares many similarities with that of Deperetella especially in having elongated and slender limbs, a relatively long, narrow lunar with a slightly concave medial border of the radial facet, a magnum with an anteriorly situated hump and a deeply excavated Mc IV facet, Mc II not elevated above Mc III, a slightly asymmetric trochlea of the femur, a fibula highly reduced or even fused with a tibia, Mt III contacting the cuboid, Mt II in contact with ectocuneiform only on the posterior end, and the manus and pes with functional tridactyls. These similarities support the close relationship between Teleolophus and Deperetella. We interpreted some similarities of postcrania between Teleolophus and Lophialetes as a result of parallel evolution, due to their cursorial adaptations. Colodon is more similar to Heptodon than to Teleolophus in the postcranial features, suggesting a close relationship between Colodon and Heptodon. Whether or not Helaletidae and Deperetellidae are closely related await further investigation. Both morphological characters and ternary diagram indicate that Teleolophus adapted to fast running, as its contemporary Lophialetes.

submitted time 2018-01-25 From cooperative journals:《古脊椎动物学报》 Hits5741Downloads1993 Comment 0

8. chinaXiv:201711.01893 [pdf]

Dentition of Subengius mengi (Mammalia: Plesiadapoidea) and a reassessment of the phylogenetic relationships of Asian Carpolestidae

K. Christopher BEARD; NI Xi-Jun; WANG Yuan-Qing; MENG Jin; Daniel L. GEBO
Subjects: Biology >> Zoology

New fossils pertaining to the oldest known Asian plesiadapiform, the Gashatan carpolestid Subengius mengi, clarify aspects of the dental anatomy of this taxon. The dentition of S. mengi is substantially more primitive than previously recognized in retaining a lower dental formula of 2.1.3.3, a low-crowned p4 with three main cusps that are less fully connate than their counterparts in species of Elphidotarsius, P3 with a narrower and structurally simpler lingual margin, and in lacking widely splayed paraconid and metaconid on m1. The unique structure of P3 in S. mengi and a reassessment of P3 anatomy in Elphidotarsius sp., cf. E. florencae, suggest that certain cusp homologies on P3 in Carpolestidae have been misinterpreted in the past. Following a detailed character analysis, the phylogenetic relationships of carpolestids and their close relatives are reconstructed. The Bumbanian taxon Chronolestes simul is recovered as the most basal member of Carpolestidae. S. mengi and a second Bumbanian taxon, Carpocristes oriens, also appear to be relatively basal members of the carpolestid radiation, although none of these Asian carpolestid taxa seems to be specially related to each other. Dispersal of carpolestids between Asia and North America appears to have been restricted to earlier parts of the Paleocene, although carpolestids survived on both continents until sometime near the Paleocene–Eocene boundary.

submitted time 2017-11-07 From cooperative journals:《古脊椎动物学报》 Hits2677Downloads1182 Comment 0

9. chinaXiv:201711.01894 [pdf]

The incisor enamel microstructure of Mina hui (Mammalia, Glires) and its implication for the taxonomy of basal Glires

MAO Fang-Yuan; LI Chuan-Kui; WANG Yuan-Qing; LI Qian; MENG Jin
Subjects: Biology >> Zoology

The incisor enamel microstructure of Mina hui Li et al., 2016 from the upper Wanghudun Formation, Middle Paleogene of Qianshan, Anhui is described following the hierarchical system ranging from crystallites to Schmelzmuster. The enamel sample was taken from the upper incisor of the holotype. The enamel consists of a very thin prismless external layer, a relatively thick outer layer (PE) with radial enamel and an inner layer (PI) with multilayered Hunter-Schreger bands (HSB). The thickness of HSB is irregular and the inclination has a small angle; no transition zones between the HSB; prism cross sections are irregularly round; interprismatic matrix is very thick with crystallites in the PE running parallel to the prism long axes. These characters resemble pauciserial HSB in rodents. Ribbon-like prism seams and convergent crystallite discontinuities are consistent in different portions of the enamel, which are interpreted as a primitive feature for Glires, or even placental mammals. Compared with known enamel structure of basal Glires, the enamel of Mina stands for the earliest known evidence of double-layered enamel of the group. It indicates that the early evolution of Glires and placental mammals is complex and adds more details to the enamel microstructure of the earliest Glires.

submitted time 2017-11-07 From cooperative journals:《古脊椎动物学报》 Hits2564Downloads1098 Comment 0

10. chinaXiv:201711.01898 [pdf]

A new mimotonidan Mina hui (Mammalia, Glires) from the Middle Paleocene of Qianshan, Anhui, China

LI Chuan-Kui; WANG Yuan-Qing; ZHANG Zhao-Qun; MAO Fang-Yuan1MENG Jin
Subjects: Biology >> Zoology

Here we report a new genus and species, Mina hui gen. et sp. nov., of basal Glires from the Middle Paleocene of Qianshan, Anhui, China. The new taxon is characterized by combination of the following characters: medium-sized mimotonidan; upper dental formula 2.0.3.3; d I2 transversely narrow and having smooth labial surface without longitudinal groove; M1 the largest cheek tooth and other cheek teeth decreasing in size considerably away from M1 so that the external margin of the upper cheek tooth row is distinctly arched labially; lingual side of upper molars unilaterally hypsodont and bearing no hypostria; hypocone being slightly distolingual to protocone; presence of a mesostyle; upper incisor with double-layered enamel structure; posterior border of anterior root of zygoma situated lateral to M1–2 and infraorbital foramen positioned low. M. hui is one of the earliest known Glires, co-existing with Heomys and Mimotona in Qianshan geographically and Middle Paleocene (ca. 61 Ma) chronologically. We consider that the Mimotonida would include two families: the monotypic Mimotonidae that contains Mimotona and Mimolagidae that includes Mimolagus, Gomphos, Anatolimys, Mina and possibly Amar aleator. Among known mimotonidans, Mimotona probably represents a primitive “morphotype” as the ancestor of lagomorphs, whereas Mimolagidae includes a side branch diverged from the clade evolved toward lagomorphs. Future research may show that Mimolagidae is not a natural group, and may possibly submerge into Mimotonida, or involve more than one family-level clade. The occurrence of Heomys, Mimotona and Mina from Qianshan show that Glires had already diversified by the Middle Paleocene.

submitted time 2017-11-07 From cooperative journals:《古脊椎动物学报》 Hits2692Downloads1255 Comment 0

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