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1. chinaXiv:202104.00006 [pdf]

Climate change and evolution of early lagomorphs (Mammalia): a study perspective based on new materials of Ordolagus from Nei Mongol (northern China)

Chiara ANGELONE; ZHANG Zhao-Qun
Subjects: Biology >> Zoology

The Early Oligocene is a critical time for global climate changes in the Cenozoic. This epoch witnessed severe mammalian faunal turnovers known as “Grande Coupure” in Europe and “Mongolian Remodelling” in Asia. However, insights about morphological changes in Oligocene mammal lineages have not been explored in detail. One of the least diversified groups of recent mammals, lagomorpha, is globally common in the fossil records, especially in Asia. During the Oligocene, many Eocene archaic lagomorph taxa died out and were replaced by more advanced forms. New findings from Nei Mongol and re-examination of the specimens from older collections enabled a revision of a common Asian lagomorph genus, Ordolagus, which possibly has a close affinity with the Middle–Late Eocene genus Gobiolagus. In Nei Mongol, we recognized the presence of Ordolagus during the basal Early Oligocene. Comparisons with coeval and slightly older lagomorph taxa from Asia and North America show that Ordolagus attained some salient tooth morphological characters (i.e., development of anteroconid on p3, full hypselodonty of cheek teeth, and lingual connection of trigonid and talonid on p4–m2), which are also the key features of modern leporids. The appearance of those morphologic features in Ordolagus is coeval to major global or regional climatic changes. Further investigations on Asian early lagomorphs compared with the study of other small mammals and local climatic factors will be essential to refine the role of lagomorphs as palaeoclimatic proxies.

submitted time 2021-04-02 From cooperative journals:《古脊椎动物学报》 Hits201Downloads98 Comment 0

2. chinaXiv:202104.00007 [pdf]

An Upper Miocene “Hipparion fauna” locality sandwiched by basalts in Hanjiaying, Nei Mongol

WANG Qian;LIU Yan;WANG Li-Hua; Mikael FORTELIUS; ZHANG Zhao-Qun
Subjects: Biology >> Zoology

Here we report a Hipparion fauna locality discovered in between two basalt layers near Hanjiaying Village, Jining District, Wulanchabu City, Nei Mongol. K-Ar isotopic dating of the lower and upper level of the basalt constrains the age of the fauna from 7.2 to 6.8 Ma. Compared with classical Hipparion fauna from northern China, the Hanjiaying fauna is closer to those from Baode of Shanxi, Siziwang Banner of Nei Mongol and the Linxia Basin of Gansu. It is similar to the Loc. 43, 44 and 49 from Baode by faunal composition, confirming their age to be ~7.0 Ma rather than 5.5 Ma. The high similarity with the fossils from Wulanhua, Siziwang Banner, Nei Mongol, verified the age of Wulanhua fauna at about 7 Ma. Compared with faunas from the Linxia Basin, Gansu, it is more similar to those from the upper part of the Liushu Formation, especially the Yangjiashan fauna. Based on the faunal composition and their tooth morphology, the Hanjiaying fauna could be included in the “Gazella dorcadoides” fauna, which is supposed to be at the west paleobiome in northern China during the Late Miocene.

submitted time 2021-04-02 From cooperative journals:《古脊椎动物学报》 Hits139Downloads58 Comment 0

3. 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》 Hits8484Downloads981 Comment 0

4. 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》 Hits8630Downloads942 Comment 0

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