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  • Reappraisal of some perissodacyl fossils from the Middle Eocene of the Lijiang Basin, Yunnan, China with a revision of tapiroid Diplolophodon

    分类: 生物学 >> 动物学 提交时间: 2022-08-02 合作期刊: 《古脊椎动物学报》

    摘要:云南西部丽江盆地中始新世丽江组中的哺乳动物群以奇蹄类占据优势,之前已经报道了13个种,丽江动物群的时代被认为从伊尔丁曼哈期延续到沙拉木伦期。重新研究了丽江盆地的部分奇蹄类化石,认为Rhodopagus yunnanensis是Lijiangia zhangi 16 Vertebrata PalAsiatica的次同物异名,而后者具有和Lophiohippus相似的特征,所以将Lijiangia置于古兽科(Palaeotheriidae)的Anchilophini, 而不是最初有疑问地归入的蹄齿犀科(Hyracodontidae)。Lunania也代表了一类和Paranchilophus相似的古兽而不是爪兽;如果Lophiohippus的正型标本代表了Lunania的上臼齿,那么Lophiohippus是Lunania的次同物异名。通过对戴氏貘科(Deperetellidae) Diplolophodon的厘定,认为该属包括了3个种:D. similis, D. lunanensis 和D.xiangshanensis (新组合), 其中丽江盆地的Teleolophus xiangshanensis应归入到Diplolophodon xiangshanensis。丽江盆地的奇蹄类化石组合和垣曲盆地河堤组任村段的奇蹄类化石相似性最高,且丽江动物群的时代应限于中始新世沙拉木伦期

  • Xitunaspis, a new eugaleaspid fish (Eugaleaspiformes, Galeaspida) from the Lower Devonian of Qujing, Yunnan

    分类: 生物学 >> 动物学 提交时间: 2022-04-16 合作期刊: 《古脊椎动物学报》

    摘要:A new genus and species of the family Eugaleaspidae (Eugaleaspiformes, Galeaspida), Xitunaspis magnus gen. et sp. nov., is described from the Lower Devonian Xitun Formation in Qujing, Yunnan Province, China. The new genus displays the diagnostic characters of the Eugaleaspidae, including a slit-like median dorsal opening, no inner cornual process, developed median dorsal canals, and only three pairs of lateral transverse canals extending from lateral dorsal canals. Different from the other eugaleaspids, X. magnus possesses a large headshield with thick dermal bone and a more plesiomorphic sensory canal system. The phylogenetic analysis of the Galeaspida reveals that Xitunaspis clusters with Dunyu and Eugaleaspis to form a monophyletic clade Eugaleaspidae Liu, 1965, and has a closer relationship with Dunyu than Eugaleaspis by sharing the thick dermal bone of the headshield. The new finding represents the first convincing fossil record of the Eugaleaspiformes in the middle Lochkovian Xitun Formation and adds to our knowledge about the morphology of eugaleaspiforms and the evolutionary pattern of the sensory canal system in the Eugaleaspiformes and even Galeaspida.

  • New fossils of small and medium-sized bovids from the Early Pleistocene Site of Shanshenmiaozui in Nihewan Basin, North China

    分类: 生物学 >> 动物学 提交时间: 2022-04-16 合作期刊: 《古脊椎动物学报》

    摘要:Shanshenmiaozui site in Nihewan Basin in North China is a recently discovered Early Pleistocene site which yields rich and diverse mammalian fossils. In the fauna, the small and medium-sized bovid fossils are well represented and can be referred to the following taxa: Spirocerus wongi, Gazella sinensis, Ovis shantungensis and Megalovis piveteaui respectively, among which G. sinensis is the dominate species. S. wongi and G. sinensis are mainly represented by horn-cores and partial skull bones as well as mandibles; in addition, metacarpal and/or metatarsal bones were also recognized for all of the four species. The horn-cores are easy to be identified to the species level, while the dentitions and the postcranial bones underwent a series of examinations and comparisons before getting properly determined and referred to the most approximate taxa. Among the postcranial bones, the metapodials, especially to the metacarpal bones special attentions were paid, which are crucial not only for taxonomic identification, but also for phylogenetic and paleoecological reconstructions; the previously misidentified metapodial specimens in Nihewan fauna were reconsidered in this paper. In the SSMZ fauna, the bovid guild is dominated by Gazella and Bison, which indicates steppe was the most important biome in Nihewan Basin during Early Pleistocene.

  • Attributing “Gomphotherium shensiense” to Platybelodon tongxinensis, and a new species of Platybelodon from the latest Middle Miocene

    分类: 生物学 >> 动物学 提交时间: 2022-04-16 合作期刊: 《古脊椎动物学报》

    摘要:Platybelodon is the predominant proboscidean of northern China’s Middle Miocene. However, the cranial and cheek tooth morphologies are not clearly diagnosed. In particular, the differential diagnoses between Platybelodon and Gomphotherium have not been comprehensively examined. Here we restudied the cranium previously identified as Gomphotherium shensiense. The upper tusks lack an enamel band, the rostrum is long and narrow, the facial part is rostrally positioned, and a large “prenasal slope” is present. These characters are distinct from those of any species of Gomphotherium, but fit well with some primitive species of Platybelodon, i.e., P. tongxinensis and P. danovi. The molars are also close to the type specimen of P. tongxinensis in the tetralophodont M3 with mesiodistally wide interlophs, curved outline, and a tendency of cementodonty. In this article, we synonymized Gomphotherium shensiense with P. tongxinensis. Moreover, we recognized a new species, Platybelodon tetralophus, from the P. grangeri material collected by the AMHN expedition in Tunggur region. Platybelodon tetralophus differs from P. grangeri and the other species in the tetralophodont M2 and m2, representing the most derived species within Platybelodon. It has only occurred in the uppermost horizon of the Tunggur Formation, i.e., the Tamuqin Fauna (Platybelodon Quarry and Wolf Camp Quarry of AMHN). This work is a comprehensive amending of the genus Platybelodon.

  • A Late Pliocene Hipparion houfenense fauna from Yegou, Nihewan Basin and its biostratigraphic significance

    分类: 生物学 >> 动物学 提交时间: 2022-01-24 合作期刊: 《古脊椎动物学报》

    摘要:Currently, there are still different views regarding the chronology of the Late Cenozoic deposits in the Nihewan Basin, which results from the contradiction between biostratigraphic correlations based on mammalian fossils and magnetostratigraphic dating results. Biostratigraphic correlations indicate that the aeolian red clay exposed in the Sanggan River canyon, the fluviolacustrine red clay with sands and gravels, and the sandy clay of swamp facies on both sides of the lower reaches of the Huliu River belong to the Upper Pliocene, whereas the magnetostratigraphic dating usually correlates them to the Lower Pleistocene. In October 2011, a collection of mammalian fossils was unearthed from a block of collapsed deposits at Yegou in the Nihewan Basin, which is about 300 m north of the Laowogou section that is well known for the Pliocene mammalian fossils from its lower part. The Yegou fossils are identified herein as 10 species in 9 genera: Nyctereutes tingi, N. sinensis, Pachycrocuta pyrenaica, Homotherium sp., Hipparion (Plesiohipparion) houfenense, Dicerorhinus sp., Muntiacus sp., Axis shansius, Gazella blacki, and Paracamelus sp. The fauna is quite different from the classic Early Pleistocene Nihewan Fauna in composition and provides new evidence for the existence of the Upper Pliocene in the Nihewan Basin. Based on a systematic description of the fauna, its composition and geological age are discussed, and the compositional features of large mammals of the Late Pliocene and the Early Pleistocene mammalian faunas in the Nihewan Basin are summarized.

  • A new species of Pteronisculus from the Middle Triassic (Anisian) of Luoping, Yunnan, China, and phylogenetic relationships of early actinopterygian fishes

    分类: 生物学 >> 动物学 提交时间: 2021-05-20 合作期刊: 《古脊椎动物学报》

    摘要:Actinopterygii, the largest group of extant vertebrates, includes Cladistia, Actinopteri (Chondrostei plus Neopterygii) and closely related fossil taxa. The extinct genus Pteronisculus belongs to a stem lineage of actinopterygian fishes represented by 11 species from the Early Triassic of Madagascar, Europe and North America, and a single species from the early Middle Triassic of China. Here, we report the discovery of a new species of this genus, Pteronisculus changae, on the basis of five well-preserved specimens from the Middle Triassic (Anisian) marine deposits exposed in Luoping, eastern Yunnan, China. The discovery documents the second convincing species of Pteronisculus in the Middle Triassic and the largest stem actinopterygian fish in the Luoping Biota, having a maximum total length of up to 295 mm. The new species possesses a toothed lacrimal, which is characteristic of Pteronisculus, but it is easily distinguished from other species of the genus by some autapomorphies, e.g., a medial process at the middle portion of the intertemporal, 21 supraneurals, and 83 lateral line scales. The results of our cladistic analysis provide new insights into the relationships of early actinopterygians and recover Pteronisculus as a sister taxon of the Carboniferous rhadinichthyid Cyranorhis at the actinopterygian stem. Based on the body form, teeth and other features, it can be deduced that Pteronisculus changae is likely a relatively fast-swimming predator, feeding on planktonic invertebrates and smaller or younger fishes known to occur in the same biota. As one of the youngest species of the genus, the new species provides additional evidence to suggest that the diversity of Pteronisculus is higher than previously thought and that the eastern Paleotethys Ocean likely constituted a refuge for species of this genus during the early Middle Triassic.

  • Discovery of Omeisaurus (Dinosauria: Sauropoda) in the Middle Jurassic Shaximiao Formation of Yunyang, Chongqing, China

    分类: 生物学 >> 生物学其他学科 提交时间: 2018-12-04 合作期刊: 《古脊椎动物学报》

    摘要:A cervical vertebra recovered from the Middle Jurassic Lower Member of the Shaximiao Formation in Town of Puan, Yunyang County, Chongqing is assigned to an species undeterminata of the sauropod dinosaur Omeisaurus based on morphological and comparative study. The centrum of this mid-cervical is much hollower than solider with extremely developed fossa/foramen complex and has a high ratio (5.05) of its anteroposterior length excluding the articular ball divided by the mean value of the posterior articular surface mediolateral width and dorsoventral height. Additional features of this cervical include central length about twice the total vertebral height, a prominent midline keel on the central ventral surface, deep and long cavities bounded by centroprezygapophyseal lamina/ intraprezygapophyseal lamina and centropostzygapophyseal lamina/intrapostzygapophyseal lamina, respectively, a coel on the dorsal half of the postzygapophyseal centrodiapophyseal fossa, long prone epipophysis extending beyond the postzygapophysis facet, anteroposteriorly length of the neural spine about half the length of the centrum, and concavities on the anterior one third lateral surface of the neural spine. Therefore, this discovery reveals new morphological information on Omeisaurus, and this Omeisaurus-bearing Puan dinosaur quarry represents the easternmost occurrence of this genus.