分类： 生物学 >> 动物学 提交时间： 2020-09-15 合作期刊: 《古脊椎动物学报》
摘要： The YJW (Yangjiawan) Cave 2 of Pingxiang in Jiangxi Province is a karst cave that developed in the Permian limestone of the Changxing Formation, which is filled with clay and grit of Late Pleistocene age. Six excavations have been conducted at the site since 2015. More than ten thousand mammalian fossils have been unearthed, and the wild boar fossils account for approximately 49%, which represents the richest wild boar fossil tooth collection of Pleistocene age in southern China. This study focuses on the studies of the canine teeth and the third molars, and mainly compares fossils of Sus peii and S. xiaozhu in South China and the data of extant S. scrofa respectively in dental morphology and odontometric data analyses which includes scatter plot analysis, regression analysis, coefficient of variation analysis and linear discriminant analysis. The typical scrofic type of the male’s lower canine teeth confirmed the identification of the suid fossils from YJW Cave 2 as S. scrofa. Although the male’s lower canines, the M2s and m3s, are among the most variable teeth in sizes, they stay in the ranges of S. scrofa; furthermore, the scatterplots of both the upper and lower third molars form two distinct clusters respectively, which can probably be attributed to sexual dimorphism rather than resulting from a mixture of different suid species. The post-Early Pleistocene suid fauna in southern China is almost only composed of S. scrofa, which is quite different from the adjacent Southeast Asia where the suid fauna is quite taxonomically diversified and dominated by the verrucosic type.
分类： 生物学 >> 动物学 提交时间： 2020-08-02 合作期刊: 《古脊椎动物学报》
摘要： To improve the Paleogene biochronological framework of the Erlian Basin, Nei Mongol and clarify the diversity of fossil rodents in this region, new tsaganomyids (Cyclomylus lohensis,Coelodontomys asiaticus) from the “Upper White” beds, cylindrodontids (Gobiocylindrodon sp.,Proardynomys sp., and Cylindrodontidae gen. et sp. indet.) from the “Middle Red” and “Lower Red” beds, and ctenodactyloids (Yuomys sp.) from the “Lower White” beds of the Erden Obo section are reported. The appearance of C. lohensis and Co. asiaticus from the Erden Obo section confirms that the age of the “Upper White” beds is Early Oligocene. The “Upper White” beds of the Erden Obo section and the top bed of the Nom Khong Obo are confirmed to belong to the same formation by both lithofacies and mammalian fossils. The different kinds of cylindrodontids found from the different horizons of the Erden Obo section show that the cylindrodontids had a high diversity and a relative continuous evolution in Eocene Asia.
分类： 生物学 >> 动物学 提交时间： 2020-08-02 合作期刊: 《古脊椎动物学报》
摘要： 新鳍鱼类是辐鳍鱼亚纲中最大的现生类群，中三叠世卢加诺鱼科则是新鳍鱼类干群中的一支，具有特化的头骨和特别高的侧腹鳞片。自1939年命名以来，卢加诺鱼科仅以瑞士东部和南部、意大利北部和西班牙东南部中三叠世海相地层安尼期/拉丁期界线附近发现的瓷鳞卢加诺鱼(Luganoia lepidosteoides)为唯一代表。根据贵州兴义中三叠世晚期(拉丁期)海相地层发现的一块较完整的精美鱼化石，命名了卢加诺鱼属一新种，祥瑞卢加诺鱼(Luganoia fortuna sp. nov.)。新种代表了卢加诺鱼科在亚洲的首次出现，表明此科的生物地理分布比之前认识的要大很多。基于新种与模式种的比较研究，修订了卢加诺鱼属的鉴定特征，揭示了该属过去一些未注意到的解剖学特征，例如存在一对眶前骨，缺少板片状的方颧骨，背鳍基部具有一狭长的裸露身体区域；臀鳍很小，与尾鳍的距离比与腹鳍更近；后匙骨缺失。此外，详细列举了中国新种与欧洲模式种的形态差异，研究结果为了解卢加诺鱼属的形态多样性提供了重要信息。
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： The elephantimorph proboscideans, Serridentinus gobiensis Osborn & Granger, 1932, and Miomastodon tongxinensis Chen, 1978, from the Middle Miocene of northern China, were revised as Zygolophodon gobiensis (Osborn & Granger, 1932). However, their phylogenetic positions are still being debated because of their intermediate morphology between the typical bunodont (Gomphotheriidae) and zygodont (Mammutidae) elephantimorphs. In the present paper, we compare their dental and mandibular morphology with that of the Eurasian Z. turicensis, Gomphotherium subtapiroideum, and G. tassyi, as well as the North American Mio. merriami and G. productum. It appears that S. gobiensis and Mio. tongxinensis share with Mio. merriami the slightly more bunodont molar morphology than that of Z. turicensis, e.g., the thicker enamel, thicker pretrite crescentoids, higher interlophid enamel pillars in buccal view, and the narrower contour majorly caused by the narrower posttrite half loph(id)s. S. gobiensis and Mio. merriami also possess an “erected oval cross-sectioned mandibular tusk”, in which the cross-section is mediolaterally compressed (dorsoventral diameter being larger than the mediolateral one). Whereas, in Z. turicensis and G. productum, the mandibular tusk is “laid oval cross-sectioned”, in which the cross-section is dorsoventrally compressed (dorsoventral diameter is smaller than the mediolateral one). Therefore, it is reasonable to revive the genus Miomastodon Osborn, 1922, which contains the species that were previously attributed to Zygolophodon, but they have relatively bunodont molar morphology (i.e., the robust type of the Z. turicensis group). The mandibular tusk with erected oval cross-section seems to be a synapomorphy of Miomastodon species. Furthermore, the molar morphology of G. subtapiroideum and G. tassyi also exhibits intermediate status between the typical bunodonts and zygodonts. However, the mandibular symphysis of G. subtapiroideum and G. tassyi is stronger than that of Miomastodon, and the mandibular tusk is pyriform cross-sectioned. The validity of Miomastodon and G. subtapiroideum/tassyi obscures the boundary between the Gomphotheriidae and Mammutidae, and suggests that the evolutions of the Gomphotheriidae and Mammutidae are deeply involved in with each other, rather than straightforwardly detached. This phenomenon has been revealed by a collagen sequence analysis among Notiomastodon, Mammut, and extant elephants, which should be further studied.
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： Many cervid specimens were uncovered during the field exploration for Nihewan beds at the beginning of the 1980s from Taijiaping, Shuichongkou and Dazhuangke localities along Xinyaozi Ravine at Nangaoya Township of Tianzhen County, Shanxi Province in North China. Recent studies on the cervid material identified seven species of Cervidae in total: Muntiacus bohlini, Cervavitus cf. C. huadeensis, Axis shansius, Nipponicervus elegans, Elaphurus davidianus predavidianus, E. bifurcatus from the Early Pleistocene deposits at Taijiaping and Shuichongkou localities, and Cervus (Elaphus) elaphus from uncertain horizon at Dazhuangke. At least the previous six species of cervids were from Nihewan Formation (Nihewanian or equivalent to European middle and late Villafranchian), i.e. the Early Pleistocene, in Sangganhe Basin area.Cervavitus cf. C. huadeensis and A. shansius were survivors from the Late Neogene; M. bohlini,N. elegans, E. davidianus predavidianus and E. bifurcatus are new forms of the Early Pleistocene.If Dazhuangke horizon can be dated as those of Shuichongkou and Taijiaping localities, the appearance of elaphoid cervids could be traced back to the Early Pleistocene, and the evolution of elaphoid antler would start from absence to presence of bez tine. The presence of Elaphurus and Nipponicervus in mainland China and Japanese archipelago implies further that the sea level was dropped down that these cervids could migrate from the mainland to the islands. The abundance of folivorous cervid specimens in the Xinyaozi Ravine area indicates the existence of a certain scale of forested environment in Sangganhe Basin area during the Early Pleistocene.
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： 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.
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： 2019-06-11 合作期刊: 《古脊椎动物学报》
摘要： The Permian dicynodont records were previously rare in North China, but many dicynodont specimens have been collected from the Naobaogou Formation in Daqingshan area, Nei Mongol since 2009. Among these specimens, seven morphotypes have been identified, and they may represent seven different species: two of them are closely related to Daqingshanodon limbus, three or four are closely related to Jimusaria sinkianensis, and one may be closely related to Turfanodon. This study shows the dicynodonts also have a high diversity at the species level in North China.
分类： 生物学 >> 动物学 提交时间： 2019-06-11 合作期刊: 《古脊椎动物学报》
摘要： The late-branching alvarezsaurian Xixianykus zhangi is among the smallest known non-avialan theropods. With great similarity to its close relatives, it is highly cursorial as indicated by proportionally long lower segments of the hindlimbs and the presence of an arctometatarsalian pes–a highly modified structure that has been suggested to improve cursorial capability in theropods. Here we describe the osteohistology of the metatarsal II of the holotype of X. zhangi (XMDFEC V 0011). Two rarely reported histological features, radial vascular canals and Sharpey’s fibers, are presented in this study. We suggest that both features are related to the development of the arctometatarsalian pes; however, further investigations of metatarsal osteohistology in theropods are required for the validation of our interpretation.
分类： 生物学 >> 动物学 提交时间： 2019-06-11 合作期刊: 《古脊椎动物学报》
摘要： The late-branching alvarezsaurian Xixianykus zhangi is among the smallest known non-avialan theropods. With great similarity to its close relatives, it is highly cursorial as indicated by proportionally long lower segments of the hindlimbs and the presence of an arctometatarsalian pes–a highly modified structure that has been suggested to improve cursorial capability in theropods. Here we describe the osteohistology of the metatarsal II of the holotype of X. zhangi (XMDFEC V 0011). Two rarely reported histological features, radial vascular canals and Sharpey’s fibers, are presented in this study. We suggest that both features are related to the development of the arctometatarsalian pes; however, further investigations of metatarsal osteohistology in theropods are required for the validation of our interpretation.
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