Numerous Neogene mammal fossils have been excavated in Hezheng location, Gansu province because the 1970s. Two fossil skulls of a bizarre bovid were discovered in current years. In an write-up
published in the journal of Science China, Dr. SHI Qinqin, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), described them as a new species, Tsaidamotherium brevirostrum. This is the second discovery of the genus in Northwest China almost 70 years immediately after the genus was initially established, sheding new light on the skull morphology and systematics of the genus.
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Holotype skull of Tsaidamotherium brevirostrum sp. nov.
[Credit: SHI Qinqin] |
Tsaidamotherium is a mid-sized late Miocene bovid with an odd-seeking horn-core apparatus so far known only from northwestern China. Through the Sino-Swedish Scientific Expedition to Northwest China in the early 1930s, two bovid cranial components with odd-looking horn-core apparatus have been collected from the Miocene deposits in the Qaidam Basin. The "absolutely exclusive horn-core apparatus" of the cranial parts seemed so peculiar and essential that these cranial parts had been assigned to a new genus and species in 1935, Tsaidamotherium hedini. Given that then not even a single specimen of Tsaidamotherium has been reported.
The holotype of Tsaidamotherium brevirostrum is a cranial element of skull with effectively-preserved horn-core apparatus, basioccipital and occipital regions. It was collected from the Liushu Formation (late Miocene) of the Linxia Basin close to the village Yancanping, approximately 2.5 km east of Maijiaji Township. Of the new specimens there is also a practically full skull of female individual, with the top element of its horn-core apparatus broken.
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Skull of female individual of Tsaidamotherium brevirostrum sp. nov.
[Credit: SHI Qinqin] |
The new species differs from the type species, T. bohlini, mainly in horn-core morphology, obtaining the frontal horn-cores correct substantially smaller and less distinctly separated from the plate-shaped posterior portion. Moreover, the new species has smaller frontal sinuses, but a thicker layer of compact bone beneath the horn-core apparatus as noticed in frontal section.
A full skull with a smaller sized horn-core apparatus is regarded as to represent a female person of T. brevirostrum. The facial element of the skull, which is initial recognized for this genus, is pretty short and higher, with a high nasal cavity, strongly retracted nasals, and shortened premaxillae and premolar rows. All this probably suggests that the animal with an enlarged nasal cavity, like the contemporary Saiga and Budorcas, might have had a specific adaptation to the higher plateau atmosphere.
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Skull reconstruction of Tsaidamotherium brevirostrum sp. nov.
[Credit: SHI Qinqin] |
Although the fossil material of Tsaidamotherium is extremely scarce, its distribution area could be a lengthy strip along the north margin of the Tibetan plateau, since the localities of the two species are pretty much 600 km apart from every single other. The distribution of this sort of animal may well even extend to Xinjiang Uygur Autonomous Region. To date, Tsaidamotherium is found only in Northwest China, and seems to be a very endemic kind there.
Source: Chinese Academy of Sciences [March 31, 2014]
