分类： 生物学 >> 动物学 提交时间： 2021-11-26 合作期刊: 《古脊椎动物学报》
摘要： The aardwolf Proteles cristatus is the only known hyaenid, living or extinct, to exhibit an extremely reduced dentition related to its termite-specializing diet. The fossil record of extant aardwolves extends to 2 to 4 million years ago, but records that inform its evolutionary origins are essentially nonexistent. Such circumstance renders it difficult to place this unusual hyena in the broader evolutionary context of small-bodied hyaenid species in Eurasian Neogene deposits. Here we describe a new genus and species of a small-bodied hyaenid, Gansuyaena megalotis, representing the closest morphological link to aardwolves to date. This new fossil hyena is based on a skull with associated mandible, a rostrum preserving several teeth, and several referred specimens. The new specimens were discovered in Neogene deposits in Linxia Basin, Gansu Province, China. Phylogenetic analysis indicates that among early hyaenids, G. megalotis is most closely related, but unlikely ancestral, to the living aardwolf. Also recognized in this new species are the fossils previously referred to “Protictitherium” aff. P. gaillardi from Pasalar, Turkey. Additionally, “Plioviverrops” guerini from Los Mansuetos, Spain is interpreted to represent a second Gansuyaena species. In addition to the living aardwolf, Proteles cristatus, our analyses suggest that the proteline lineage includes the extinct genera Gansuyaena, Mesoviverrops, and Plioviverrops. Although the precise timing and geographic location of evolutionary divergence between the aardwolf and Gansuyaena remain elusive, critical new morphological information provided by Gansuyaena specimens reinforce findings from recent genomic analyses that the aardwolf lineage has an ancient origin from small-bodied stem hyaenids prior to the appearance of large and robust bone-cracking hyaenines.
分类： 生物学 >> 动物学 提交时间： 2020-03-31 合作期刊: 《古脊椎动物学报》
摘要： A skull with mandible and several cervicals of a new species of Huerzelerimys, H.asiaticus, collected from the Late Miocene Liushu Formation in Linxia Basin, Gansu Province,is described in this paper. The skull is the first one ever found for the genus Huerzelerimys. Its main characters are: size small; skull broad and short with stout rostrum; interorbital roof narrow;premaxillary laterodorsal crest well developed; frontal crests weak and subparallel; incisive foramina long, with their posterior ends lined up with anterior root of M1; posterior palatal foramina located mesial to M2; caudal border of hard palate lying posterior to M3;interpterygoid foramen absent; alisphenoid canal bony; bulla large and inflated; internal carotid foramen located near the basilar tubercle; mandible having low horizontal ramus and deeply concave diastema; anterior end of masseteric ridge lined up with anterior margin of m1; mental foramen situated slightly anterior to masseteric ridge and anteroventral to m1, near to mandibular diastema; upper incisors orthodont; M1 having slightly anteriorly located t1; in M1 and M2 t6 and t9 connected by distinct crest and t12 crest-like; t1 and t3 of M2 and t1 of M3 connected to t5; M3 having t3 and a large isolated t8; small Acc of m1 connected with both Alc and Abc; m1 and m2 having distinct buccal cingula, larger c2 attached to protoconid, and low crest-like posterior heel; m2 and m3 having isolated Abc; c1 absent in m3. The evolutionary level of the described skull tends to show that the age of the upper part of the Liushu Formation yielding H. asiaticus may belong to late Bahean, corresponding to European upper MN11 or lower MN12.
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