分类： 生物学 >> 动物学 提交时间： 2022-10-16 合作期刊: 《古脊椎动物学报》
摘要： The saurichthyiform fishes, characterized by a pointed rostrum and a streamlined long and slender body plan, ranked among the top predators of the ichthyofauna in the Early Mesozoic oceanic ecosystem. In a cosmopolitan pattern, these fishes rapidly radiated after the end-Permian mass extinction (EPME) and diversified morphologically and ecologically during the Middle Triassic. Thereafter, they seemingly showed a notable shrinkage from a global distribution to an occurrence basically restricted to the western Paleo-Tethys realm since the Late Triassic. Specifically, there is no saurichthyiform fossil record so far from the marine Late Triassic of South China (eastern Paleo-Tethys), where contrastingly they were highly diversified in stratigraphically older Lagersttten (Middle Triassic Panxian-Luoping and Xingyi biotas). Here we report the discovery of Saurichthys taotie sp. nov. from the Guanling biota of Guizhou and Yunnan provinces, southwestern China. This new species is a medium-sized Saurichthys featured by subtriangular subopercles ornamented with densely arranged vertical striae, faint ornamentation on the posterior part of the skull roof, and strong longitudinal ridges decorating the anterodorsal surface of the rostrum. By marking its own groups first occurrence in the Late Triassic of eastern Paleo-Tethyan province, Saurichthys taotie suggests that the saurichthyiform fishes were actually much more widespread than previously thought during that geological stage when they showed a considerable decline in the diversity. By still possessing some features previously only seen in its Early Triassic congeners elsewhere, Saurichthys taotie sheds new light on the evolutionary and paleobiogeographical history of saurichthyiform fishes.
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.
分类： 生物学 >> 动物学 提交时间： 2019-08-26 合作期刊: 《古脊椎动物学报》
摘要： The Nihewan Basin has been well known for its Cezonoic fossiliferous fluviolacustrine deposits and paleolithic sites for almost a century. There have been considerable research efforts devoted to the understanding of the geology, chronology, and stratigraphy of this complex of sedimentary body. The current fundamental problem lies in the chronological aspect of the Nihewan Beds. Arvicolinae and Myospalacinae are two groups of rodents characterized by rapid evolutionary rates and quantifiable evolutionary trends, and hence particularly helpful in Late Cenozoic biostratigraphic correlations. Therefore, we briefly describe three new species of Arvicolinae and two new species of Myospalacinae that mainly came from the selected sections in the Nihewan Basin. Hopefully, they would contribute towards the establishment of the biostratigraphic framework of the Nihewan Basin and provide new evidence on the chronological understanding of the Nihewan Beds from an evolutionary point of view.
分类： 生物学 >> 动物学 提交时间： 2017-11-07 合作期刊: 《古脊椎动物学报》
摘要： Here we describe †Nanningocyprinus wui gen. et sp. nov, a fossil Cyprinus-like fish from the Early-Middle Oligocene deposits of Langdong, Nanning Basin, Guangxi Province, South China. †Nanningocyprinus wui is represented by a number of pharyngeal bones and teeth. It differs from all other cyprinid fishes in the following character combination: tooth formula —3·2·1, crushing molar-like A1 much larger than A2, only one groove on the grinding surface of A2 and B1 respectively, and the anterior angle of the pharyngeal bone triangular and prominent. The new-found Cyprinus-like fish, along with the previously known Late Eocene †Eoprocypris maomingensis (Procypris-like) and Oligocene †Huashancyprinus robustispinus (Cyprinus-like) from South China, further indicates an early branching and diversification of the Cyprininae (Cyprinidae) in this area.
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