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    Nothosaurus luopingensis sp. nov. (Sauropterygia) from the Anisian, Middle Triassic of Luoping, Yunnan Province, China
    SHANG Qing-Hua, LI Chun, WANG Wei
    Vertebrata Palasiatica    2022, 60 (4): 249-270.   DOI: 10.19615/j.cnki.2096-9899.220524
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    Nothosaurus luopingensis sp. nov. from Member II of the Guanling Formation (Anisian, Middle Triassic) of Luoping, Yunnan, China is described based on a specimen comprising the skull and most of the postcranial skeleton. The specimen is assigned to Nothosaurus of Eosauropterygia as suggested by a series of skull characters, such as the maxillary tooth row extending posteriorly beyond the level of the anterior margin of the upper temporal fenestra, the longitudinal diameter of the upper temporal fenestra more than twice as long as that of the orbit, and the presence of maxillary fangs. Compared with Lariosaurus, the following morphological features of the pectoral girdle and the limbs also support the assignment of the specimen to Nothosaurus, i.e., the clavicles with expanded anterolateral corners, the characteristically curved humerus with a straight preaxial angle and a postaxial concavity, the distinct deltopectoral crest on the proximal part of the humerus, no hyperphalangy in the manus, and the absence of pachyostosis in the vertebrae and ribs. On the other hand, the specimen possesses some postcranial features that were previously considered to occur mainly in Lariosaurus, such as more than three ossifications in the carpus, four sacral ribs, and an interclavicle without any trace of a posterior stem. These postcranial characters may no longer be used as the diagnostic features of Lariosaurus. Nothosaurus luopingensis is distinguished from other Nothosaurus species by a unique combination of derived characters, including that the jugal enters the orbit, the nasals are separated, the posterior end of the frontal is bifurcate, pedal digits V and IV are long and subequal in length, and the ungula phalanx is stout. Our phylogenetic analysis corroborates the monophyly of Nothosaurus and suggest that N. luopingensis is the sister group of N. yangjuanensis.

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    Vayu 1.0, a new set of tools for visualizing surface meshes
    LU Jing
    Vertebrata Palasiatica    2023, 61 (1): 71-80.   DOI: 10.19615/j.cnki.2096-9899.221020
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    Vayu 1.0 is a freeware that deals with surface mesh files. It provides a set of tools for rendering, labelling, revisualizing, and reanalyzing meshes. It also offers features for VR mode and one-stop animation production. This paper describes the major features of Vayu 1.0, which includes three main panels, i.e. mesh information, keyframe editor, and shading-transform. Vayu, as an innovative freeware, contains the state-of-the-art new features which provides a fresh set of tools to accelerate future development directions in paleontology, biological sciences and beyond.

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    A new specimen of Parabohaiornis martini (Avialae: Enantiornithes) sheds light on early avian skull evolution
    WANG Min
    Vertebrata Palasiatica    2023, 61 (2): 90-107.   DOI: 10.19615/j.cnki.2096-9899.230217
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    The Enantiornithes is the most speciose clade of Mesozoic avialans with over 60 named taxa reported from most continents that span the whole Cretaceous. Most of the fossil remains of this clade, as well as those of other early diverging avialans are preserved in two-dimensions. This complicates efforts to extract detailed anatomical information from the skull, in which the composite elements are delicate and thus not easily observable through conventional methods. The scarcity of well-preserved early avialan skulls, as well as the limited number of specimens that have been analyzed using computed tomography scanning, consequently circumscribes a large morphological gap in the fossil record during the transition from the heavy and akinetic dinosaurian skull to the lightweight and kinetic bird skull. Here, we present a three-dimensional digital reconstruction of the skull and part of the cervical vertebrae of a new specimen of the enantiornithine Parabohaiornis martini from the Early Cretaceous of China. Our results demonstrate that Parabohaiornis retains the plesiomorphic non-avialan dinosaurian temporal and palatal configurations, reinforcing the recent hypothesis that the temporal and palatal regions are evolutionarily conservative and that the akinetic skull has been conserved well into diversification of early branching avialans.

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    First record of Saurichthys (Actinopterygii: Saurichthyidae) from the Late Triassic of eastern Paleo-Tethys
    FANG Geng-Yu, SUN Yuan-Lin, JI Cheng, WU Fei-Xiang
    Vertebrata Palasiatica    2023, 61 (1): 1-16.   DOI: 10.19615/j.cnki.2096-9899.221013
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    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 Lagerstätten (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 group’s 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.

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    The pelvic morphology of Parayunnanolepis (Placodermi, Antiarcha) revealed by tomographic data
    ZHU You-An, WANG Ya-Jing, QU Qing-Ming, LU Jing, ZHU Min
    Vertebrata Palasiatica    2023, 61 (2): 81-89.   DOI: 10.19615/j.cnki.2096-9899.221126
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    The pelvic morphology, and whether the pelvic fin is present or absent in the earliest jawed vertebrates are key in interpreting the origin of vertebrate paired fins. Parayunnanolepis xitunensis, an antiarch placoderm from the Early Devonian of Yunnan, South China, was previously described to possess the earliest evidence of both dermal and endoskeletal pelvic girdles, presumably for the attachment of the pelvic fins. Here, we redescribe the pelvic region of the holotype based on high-resolution computed tomographic data. Instead of having two large plates previously designated as dermal pelvic girdles, Parayunnanolepis possesses three pairs of lateral pelvic plates, and one large oval median pelvic plate. The paired pelvic plates are flat ventral plates, and differ from other dermal pelvic girdles in lacking a dorsal extension. There is no definitive evidence for the presence of an endoskeletal pelvic girdle in Parayunnanolepis, although the possibility cannot be ruled out. A comparison of the dermal pelvic plates in various jawed stem-gnathostomes suggests the presence of both paired and median pelvic plates is shared by different lineages and might be plesiomorphic. The jawed stem-gnathostomes may have recruited the ventral dermal skeleton of the post-thoracic body into different functional units.

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    A new Late Triassic tetrapod locality from North China
    SHI Yu-Tai, CHEN Jian-Ye, LIU Jun
    Vertebrata Palasiatica    2023, 61 (1): 17-25.   DOI: 10.19615/j.cnki.2096-9899.220818
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    No definite tetrapod body fossil is known from the Late Triassic of North China. Here we report new tetrapod remains from the Upper Triassic Tanzhuang Formation of Jiyuan, Henan Province. Most of the specimens can be referred to the temnospondyls, and show affinity with Mastodonsaurus. Previously, Mastodonsaurus is only know from Europe. So that, this finding indicates that a clade including Mastodonsaurus and its close relatives had a wide distribution from Europe to East Asia during the Late Triassic. A possible pelvis indicates the presence of another tetrapod group. This discovery fills a tetrapod body record gap in Chinese Late Triassic.

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    A Late Pliocene Hipparion houfenense fauna from Yegou, Nihewan Basin and its biostratigraphic significance
    LIU Jin-Yi, ZHANG Ying-Qi, CHI Zhen-Qing, WANG Yong, YANG Jin-Song, ZHENG Shao-Hua
    Vertebrata Palasiatica    2022, 60 (4): 278-323.   DOI: 10.19615/j.cnki.2096-9899.211209
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    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 fluvio-lacustrine 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.

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    First discovery of dinosaur eggs in Nanhu Gebi of Hami, Xinjiang, China
    WANG Qiang, XING Hao, SHI Hai-Tao, FANG Kai-Yong, ZHU Xu-Feng, ZHOU Ming-Xiao, WANG Xiao-Lin
    Vertebrata Palasiatica    2022, 60 (4): 324-327.   DOI: 10.19615/j.cnki.2096-9899.220801
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    Here we report the first dinosaur eggshells found in the Nanhu Gebi of Hami, including Elongatoolithus elongatus and Ovaloolithus oosp. The discovery of these dinosaur eggs not only enlarge the palaeogeographic distribution of elongtaoolithid and ovaloolithid eggs, but also indicate the geological age of egg-bearing strata to be the end of Late Cretaceous. Whether the strata can be correlated with the Subashi Formation in Turpan Basin remains to be clarified.

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    Taxonomic revision of Sinoeugnathus kueichowensis (Halecomorphi, Holostei) from the Middle Triassic of Guizhou and Yunnan, China
    FENG Dong-Hao, XU Guang-Hui, MA Xin-Ying, REN Yi
    Vertebrata Palasiatica    2023, 61 (3): 161-181.   DOI: 10.19615/j.cnki.2096-9899.230703
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    The previously alleged ‘eugnathid amiiform’ Sinoeugnathus kueichowensis is a small-sized halecomorph from the Middle Triassic (Ladinian) marine deposits of Guizhou and Yunnan, China. A morphological redescription and taxonomic revision of this taxon are provided based on a detailed examination of the holotype and 15 new specimens. Studies of these specimens revealed some morphological details previously undescribed or misidentified for this taxon, including a hatchet-shaped antorbital, two broad suborbitals, a sensory canal in the maxilla, and three pairs of extrascapulars. For the first time, Sinoeugnathus was incorporated into an analysis of halecomorph phylogeny, and the results recover it as the sister taxon of the Anisian Subortichthys from Luoping, Yunnan, and both are grouped with two Ladinian genera Allolepidotus and Eoeugnathus from the Monte San Giorgio area into a monophyletic group (namely Subortichthyidae fam. nov. herein) at the base of Ionoscopiformes. This taxonomic reassessment of Subortichthys provides new insights into the phylogeny and paleogeographic evolution of Ionoscopiformes.

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    A new species of Pararhizomys (Tachyoryctoidinae, Muroidea) from Linxia Basin of Gansu Province
    WANG Ban-Yue
    Vertebrata Palasiatica    2022, 60 (4): 271-277.   DOI: 10.19615/j.cnki.2096-9899.220403
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    An anterior part of skull was recently found near Xiayangwan in Guanghe County, Gansu Province, presumably from the Liushu Formation. The skull represents a new species of Pararhizomys, named as Pararhizomys parvulus. The new species is characterized by: small size, upper molars higher crowned and mesio-lingually hypsodont with sinus deeper than mesosinus; sinus and mesosinus in M3 being transverse and overlapping each other, but sinus longer than mesosinus on occlusal view. Based on shared apomorphies (lingually hypsodont upper molars and transverse sinus and mesosinus on M3 occulsal surface), P. parvulus and P. huaxiaensis are supposed to form a sister group. However, P. parvulus may be more derived than P. huaxiaensis as demonstrated by the more hypsodont molars and the deeper sinus in M3.

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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
    BAI Bin
    Vertebrata Palasiatica    2023, 61 (1): 26-42.   DOI: 10.19615/j.cnki.2096-9899.220721
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    The Lijiang Fauna from the Lijiang Formation of Lijiang, western Yunnan, was dominated by 13 species of perissodactyl fossils, and its age ranged from Irdinmanhan to Sharamurunian Asian Land Mammal Ages (ALMA) according to previous research. Based on reanalysis of some perissodactyls from the Lijiang Fauna, it is suggested here that Rhodopagus yunnanensis is a junior synonym of Lijiangia zhangae, which is similar to Lophiohippus and placed in Anchilophini within the Palaeotheriidae. The enigmatic and scarce Lunania is here regarded as a palaeothere rather than a chalicothere based on its morphological similarities with Paranchilophus, and Lophiohippus probably represents the upper dentitions of Lunania. Furthermore, deperetellid Diplolophodon is revised and comprised of three species: D. similis, D. lunanensis, and D. xiangshanensis (comb. nov.). Teleolophus xiangshanensis from the Lijiang Formation is reassigned to Diplolophodon xiangshanensis. The revised perissodactyls from the Lijiang Fauna are comparable to those from the Rencun Member of the Hedi Formation of the Yuanqu Basin, and its age is confined to Sharamurunian ALMA.

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    Ulanodon, a new name for the Hyracodontid Ulania Qi, 1990 (Perissodactyla, Mammalia)
    BAI Bin, QI Tao
    Vertebrata Palasiatica    2022, 60 (4): 328-329.   DOI: 10.19615/j.cnki.2096-9899.220722
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    Qi ( 1990a ) named a new hyracodontid genus Ulania from the Middle Eocene deposits of Nei Mongol (Inner Mongolia), China. However, the generic name has been preoccupied by Ulania Lin & Zhang, 1979 , a Cambrian trilobite (Zhu, et al., 1979 ). We therefore propose a new generic name Ulanodon nom. nov. to replace Ulania Qi, 1990 .

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    Mansancun Micromammal Fauna from the upper part of the Jiaozigou Formation in Linxia Basin, Gansu Province
    WANG Ban-Yue, QIU Zhan-Xiang, WANG Shi-Qi
    Vertebrata Palasiatica    2023, 61 (2): 123-141.   DOI: 10.19615/j.cnki.2096-9899.230112
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    The micromammal fossils collected from the upper part of the Jiaozigou Formation near Mansancun in 2015 are described. The sample consists of 10 species of six previously known genera (Amphechinus, Sinolagomys, Parasminthus, Litodonomys, Heterosminthus and Yindirtemys) belonging to three orders. Of them, four genera (Sinolagomys, Litodonomys, Heterosminthus and Yindirtemys) made their first appearance in the Late Oligocene and Sinolagomys kansuensis and Heterosminthus lanzhouensis are known only in the Late Oligocene. In comparison with the other Late Oligocene mammalian faunas known in China and Mongolia, the above assemblage appears to be contemporaneous with Xiagou, Taben-buluk, Yikebulage faunas and Tieersihabahe assemblages, but slightly younger than the Shargaltein-Tal Fauna in age. The Mansancun Fauna is also younger than the three Late Oligocene biozones recognized recently in Asia. Compared with the Yagou Fauna collected from the lower part of the Jiaozigou Formation, the Mansancun Local Fauna is clearly younger. Consequently, the Yagou Fauna would be early Late Oligocene, while the Mansancun Local Fauna may be considered late Late Oligocene. Thus, as a whole, the Jiaozigou Formation is Late Oligocene in age.

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    New zygolophodonts from Miocene of China and their taxonomy
    ZHANG Xiao-Xiao, YANG Xu, SUN Yan, WANG Hong-Jiang, YANG Rong, CHEN Shan-Qin, WANG Shi-Qi, LI Hong
    Vertebrata Palasiatica    2023, 61 (2): 142-160.   DOI: 10.19615/j.cnki.2096-9899.230308
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    The zygodont proboscideans from the Miocene strata of China are widely distributed. However, the materials are scarce, and their classification has experienced a longtime controversy, from the chaotic state of multiple Zygolophodon species to the only one species, Zygolophodon gobiensis. The combined species Z. gobiensis comprises both the gracile type with a high degree of zygodonty and the robust type that is between the typical bunodont and zygodont morphology. Recently, as the robust type has been re-allocated to another genus Miomastodon and new fossil remains were discovered, it is necessary to further evaluate and classify the zygodont proboscideans from the Miocene of China. In the present paper, we restudied the previously published zygodont specimens of the gracile type, as well as several unpublished Mammutidae specimens. The former including Z. nemonguensis, Z. gromovae, Z. jiningensis, Z. chinjiensis and two specimens of Gomphotherium xiaolongtanensis, represents Zygolophodon in the original sense in China. In these specimens, the tip of the loph(ids) are sharp. The anterior and posterior pretrite central conules are absent or very weak, and the anterior and posterior crescentoids are sharp and slender. The posttrite mesoconelets are well subdivided and the zygodont crests are developed. In buccal view, the loph(id)s are “Ʌ-shaped” and the interloph(id)s are “V-shaped”. Their molar morphology resembles that of Z. turicensis, and hereby, they were identified as Zygolophodon cf. Z. turicensis. Several unpublished specimens from Hezheng, Gansu, Tunggur, Nei Mongol, Tongxin, Ningxia and Junggar, Xinjiang exhibit a lower degree of zygodonty, corresponding to the “robust type of Zygolophodon” in which the molar morphology is between the typical bunodonts and zygodonts. The pretrite crescentoids are thicker than Zygolophodon cf. Z. turicensis, and the pretrite central conules usually present on the first and second interloph(id)s. According to the stratigraphic age and characteristics, two species, Miomastodon gobiensis and Mio. tongxinensis were identified. The anterior and posterior pretrite crescentoids of Mio. tongxinensis are weaker and the pretrite central conules are larger than Mio. gobiensis. Geographical distribution indicates that Miomastodon is the predominant member of zygolophodonts in the Early and Middle Miocene in northern China. The discovery of new materials and the reclassification of zygolophodonts provide further evidence for dispersal of Mammutidae from Eurasia to North America and the evolutionary relationships among the species of the family Mammutidae in China.

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    The first description of Equidae (Perissodactyla, Mammalia) from Xinyaozi Ravine in Shanxi, North China
    DONG Wei, BAI Wei-Peng, LIU Wen-Hui, ZHANG Li-Min
    Vertebrata Palasiatica    2023, 61 (3): 212-244.   DOI: 10.19615/j.cnki.2096-9899.220926
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    Abundant mammalian fossils were uncovered during the field exploration for Nihewan beds at the beginning of the 1980s along Xinyaozi Ravine at Nangaoya Township of Tianzhen County, Shanxi Province in North China. But most equid material was not yet described except that of Equus stenonis. Six forms of Nihewanian equids were confirmed from the Xinyaozi specimens in the present study, five of which were described for the first time. They include four stenonids such as Equus sanmeniensis, E. teilhardi, E. huanghoensis and E. stenonis, and two hipparionines such as Hipparion (Proboscidipparion) sinense and H. (Plesiohiparrion) shanxiense. The diversification of stenonids in the Early Pleistocene was significant in North China with four taxa in Xinyaozi alone. The persistence of Neogene relics such as hipparionines was still present in the Early Pleistocene with two hipparionine taxa in Xinyaozi. Equus sanmeniensis and H. (Proboscidipparion) sinense were two representative equids not only coexisted in the Early Pleistocene but also widely distributed in China. The diversity of equids also implies the diversified vegetation on which they depended. The hypsodont dentitions and well developed cement, as well as completely molarized premolars of Xinyaozi equids indicate their abrasive diet mostly on monocotyledonous and grassland habitats with considerable scales enough to nourish six taxa of equids.

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    Restudy of Rhinocerotini fossils from the Miocene Jiulongkou Fauna of China
    LI Shi-Jie, DENG Tao
    Vertebrata Palasiatica    2023, 61 (3): 198-211.   DOI: 10.19615/j.cnki.2096-9899.230630
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    All the extant rhino species belong to Rhinocerotini and either have one horn (a nasal horn) or two horns (a nasal horn and frontal horn). So far, the earliest Rhinocerotini to have been identified in China is the “Dicerorhinuscixianensis, which was based on a juvenile skull with an associated mandible from the Middle Miocene locality of Jiulongkou in Cixian County, Hebei Province of northern China. Our analyses suggest that there are similarities between this specimen and the modern genus, Dicerorhinus, but it differs in several cranial traits and therefore cannot be assigned to the modern genus. Instead, it is closer to the Middle Miocene Lartetotherium from Europe, especially the specimen from La Retama in Spain and should be assigned to that genus, indicating the presence of intracontinental dispersal at this time. The Jiulongkou fauna is the only Middle Miocene fauna with Rhinocerotini in China, and, together with the faunal composition, this implies a more humid and closed environment, in contrast to those found in western China. We suggest that the position of the posterior border of the nasal notch is a good indication of the specimen’s evolutionary level in Rhinocerotini. The anterior position of the nasal notch as seen in modern Dicerorhinus, together with its certain similarities to L. cixianensis as well as its differences with more specialized species of the Dihoplus-Pliorhinus-Stephanorhinus -Coelodonta lineage, supports the conclusion that Dicerorhinus experienced little change during a nearly 10 Myr evolutionary history, possibly due to the low selection pressure seen in the tropical/subtropical forests in southeastern Asia.

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    Do chondrocytes within calcified cartilage have a higher preservation potential than osteocytes?A preliminary taphonomy experiment
    Alida M. BAILLEUL, WU Qian, LI Dong-Sheng, LI Zhi-Heng, ZHOU Zhong-He
    Vertebrata Palasiatica    2023, 61 (2): 108-122.   DOI: 10.19615/j.cnki.2096-9899.230309
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    Chondrocytes with remnants of nuclei and biomolecules were recently reported in two Cretaceous dinosaurs from North America and China. For multiple reasons, it was hypothesized that calcified cartilage (CC) had a better potential than bone to preserve ancient cells. Here we provide the first experimental test to this hypothesis by focusing on the most important variable responsible for cellular preservation: the postmortem blockage of autolysis. We compare the timing of autolysis between chondrocytes and osteocytes in an avian model (Anas platyrhynchos domesticus) buried for up to 60 days under natural conditions that did not inhibit autolytic enzymes. Within 15 days post-burial, almost all osteocytes were already cytolyzed but chondrocytes in CC were virtually unaffected. All osteocytes were cytolyzed after 30 days, but some chondrocytes were still present 60 days post-burial. Therefore, even in harsh conditions some CC chondrocytes still survive for months postmortem on a time scale compatible with permineralization. This is consistent with other data from the forensic literature showing the extreme resistance of hyaline cartilage (HC) chondrocytes after death and does support the hypothesis that CC has a better potential than bone for cellular preservation, especially in fossils that were not permineralized rapidly. However, because the samples used were previously frozen, it is possible that the pattern of autolysis observed here is also a product of cell death due to ice crystal formation and not strictly autolysis, meaning a follow-up experiment on fresh (non-frozen samples) is necessary to be extremely accurate in our conclusions. Nevertheless, this study does show that CC chondrocytes are very resistant to freezing, suggesting that chondrocytes are likely better preserved than osteocytes in permafrost fossils and mummies that underwent a freezing-thawing cycle. It also suggests that cartilage (both hyaline and calcified) may be a better substrate for ancient DNA than bone. Moreover, even though we warrant follow-up taphonomy experiments with non-frozen samples paired with DNA sequencing, we already urge ancient DNA experts to test CC as a new substrate for ancient DNA analyses in fossils preserved in hot and temperate environments as well.

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    The Sharamurunian rodent fauna in the Erlian Basin, Nei Mongol, China
    LI Qi, LI Qian
    Vertebrata Palasiatica    2023, 61 (1): 43-70.   DOI: 10.19615/j.cnki.2096-9899.221123
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    New middle Eocene rodent fossils discovered from the lower part of the Shara Murun Formation of Ula Usu, Erlian Basin, Nei Mongol, China, the classical locality of Sharamurunian mammalian fauna, were identified as 9 separate species (the ctenodactyloids Yuomys cavioides, Gobiomys neimongolensis, G. exiguus, and G. asiaticus, the dipodids Allosminthus uniconjugatus and Primisminthus shanghenus, the cricetid Pappocricetodon rencunensis, the ischyromyid Hulgana cf. H. ertnia, and the cylindrodontid Proardynomys ulausuensis) belonging to 7 genera, 4 families, and 1 superfamily of Rodentia. The Ula Usu rodent assemblage shares a high degree of similarity with that from the “Lower Red” beds of the Erden Obo, and they both represent the typical Sharamurunian rodent assemblages found in northern China. The Sharamurunian rodent fauna in the Erlian Basin is analyzed by the minimum number of individuals based on the rodent materials from the lower part of the Shara Murun Formation in the Ula Usu and the “Lower Red” beds of the Erden Obo. In the Sharamurunian rodent fauna of the Erlian Basin, ctenodactyloids are the most dominant elements, and dipodids and cricetids follow next in prevalence. By analyzing the evolution of the rodent species richness in the Erlian Basin, the rodent faunas show a transformation from a ctenodactyloid dominant assemblage to a cricetid-dipodid dominant one in chronological order. The Sharamurunian rodent fauna from the Erlian Basin differs from that of the Yuanqu Basin and the differences in the rodent assemblages may be a response to the differences between the regional environments.

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    New material of Paukkaungmeryx minutus (Cetartiodactyla, Archaeomerycidae) from the late Middle Eocene Pondaung Formation, Myanmar
    Stéphane DUCROCQ, Yaowalak CHAIMANEE, Olivier CHAVASSEAU, Aung Naing SOE, Chit SEIN, Jean-Jacques JAEGER
    Vertebrata Palasiatica    2023, 61 (3): 182-197.   DOI: 10.19615/j.cnki.2096-9899.230522
    Abstract171)   HTML13)    PDF (3229KB)(206)       Save

    We describe here new dental material from the locality of Myaukse Kyitchaung (Pondaung Formation, central Myanmar) that we refer to the primitive Archaeomerycidae ruminant Paukkaungmeryx minutus Ducrocq et al. (2020). The upper molars are morphologically very similar to those of the holotype and exhibit only slight variations on features like the better development of buccal and lingual cingula. The lower teeth display primitive characters including a simple p4 and bunoselenodont lower molars that lack folds on the back of the trigonid wall. This additional material makes Paukkaungmeryx the second archaeomerycid in Pondaung known by upper and lower teeth material, and documents the apparently complex early evolution of the family.

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