Current Location:home > Browse

Institution

1. chinaXiv:202108.00084 [pdf]

A Temnospondyl Tooth from the Middle Triassic of the Ordos Basin, Shaanxi Province

WU Rui; TU Li; HAN Feng-Lu
Subjects: Biology >> Zoology

An isolated large temnospondyl tooth was discovered from the Middle Triassic Tongchuan Formation, Weibei Oilfield, Ordos Basin, Shaanxi Province of China. Compared with the teeth of crocodylomorphs, plesiosaurs and temnospondyls, the tooth can be referred to temnospondyl based on the following features: the crown is elongated and recurved with a circular cross-section; there are no denticles or carinae on the crown; well-marked apicobasal grooves are shown on the crown surface. This tooth represents the first temnospondyl found in the Middle Triassic Tongchuan Formation and is the youngest fossil record of temnospondyls in the North China Block.

submitted time 2021-08-11 From cooperative journals:《古脊椎动物学报》 Hits4223Downloads262 Comment 0

2. chinaXiv:202108.00085 [pdf]

A cuboid bone of a large Late Miocene elasmothere from Qingyang, Gansu, and its morphological significance

ZHANG Xiao-Xiao; SUN Dan-Hui
Subjects: Biology >> Zoology

A cuboid specimen collected from the Late Miocene stratum at Qingyang, Gansu, China is described here. The size of the Qingyang specimen is comparatively huge, even larger than the average size of Elasmotherium caucasicum collected from Nihewan, Hebei, China. The morphology of the Qingyang specimen is identical to that of other specimens of Elasmotheriini; thus, the Qingyang specimen belongs to a huge elasmothere, most probably Sinotherium. By comparison with extant rhino species, the complex of the main body and the apophysis exhibit functional significance. The angle between the frontal plate of the cuboid and the main axis of the apophysis can suggest the ecological conditions occupied by an elasmothere. From analysis of the morphology of the cuboid, Sinotherium and the more derived elasmotheres probably lived in forested or wooded environments, differing from the previous hypothesis of their paleoenvironment.

submitted time 2021-08-11 From cooperative journals:《古脊椎动物学报》 Hits3706Downloads256 Comment 0

3. chinaXiv:202108.00042 [pdf]

Redescription of Nochelaspis maeandrine, the largest eugaleaspiform from the Lower Devonian of Qujing, Yunnan

MENG Xin-Yuan; ZHU Min; GAI Zhi-Kun
Subjects: Biology >> Zoology

The new specimens of the largest eugaleaspiform Nochelaspis maeandrine are redescribed from two localities of the Xishancun Formation in Qujing City, Yunnan Province, southwestern China. Nochelaspis is most suggestive of Yunnanogaleaspis from the same horizon, but differs in its slit-like median dorsal opening (length/width>6), much stronger inner cornual process, coarse stellate ornamentation, and the serrations along the edges of the median dorsal opening and headshield. The new findings reveal the morphological details on the ventral side of the headshield as well. The oralobranchial fenestra is covered by a large dermal ventral plate, which is decorated with dense, tiny granular tubercles, and aligned with six pairs of separated, large, and circular branchial openings. This condition is different from that of osteostracans, in which the oralobranchial fenestra is covered by numerous minute scales or larger dermal platelets, and the branchial openings are slit-shaped and covered by small skin flaps somewhat like those of elasmobranchs. However, the branchial openings of galeaspids and osteostracans are both located ventrally as in modern rays, indicating a benthic lifestyle dwelling on sandy or muddy substrates in a quiet marine environment.

submitted time 2021-07-30 From cooperative journals:《古脊椎动物学报》 Hits1961Downloads247 Comment 0

4. chinaXiv:202108.00043 [pdf]

On the scientific names of mastodont taxa: nomenclature,Chinese translation, and taxonomic problems

WANG Shi-Qi; LI Chun-Xiao; ZHANG Xiao-Xiao
Subjects: Biology >> Zoology

乳齿象类是长鼻类演化的重要阶段,该阶段奠定了长鼻类各冠群演化的基本格局。乳齿象类的研究有400多年的历史,分类和命名经过多次修订改动,乳齿象类的演化脉络完全体现在乳齿象命名历史之中。从词源学角度考证乳齿象类各类群的命名来源,整理了175条乳齿象类的中文译名(绝大多数为有效分类名), 包括12个属以上分类群,46个属,117个种,涵盖了乳齿象类几乎全部的种属。在此基础上梳理了乳齿象类的演化脉络,提出乳齿象类分类和命名中存在的一些问题。乳齿象类的头骨和下颌的演化在各支系中都是连续的,体现出了相近的平行演化趋势,而颊齿的形态特征虽然区别不明显,但在各支系中相对稳定。豕棱齿象科(Choerolophodontidae)是乳齿象类中最稳健的单系群,其中厚棱象(Synconolophus)可能是有效属名;玛姆象科中,中新乳齿象(Miomastodon)和上新乳齿象(Pliomastodon)可能都是有效的,但不一定是美洲乳齿象(Mammut americanum)的直接祖先;铲齿象科(Amebelodontidae)中达氏铲齿象(Platybelodon danovi)与格氏铲齿象(P. grangeri)、赵氏隐门齿象(Aphanobelodon zhaoi)的系统发育关系存在疑问,取决于P.danovi的下门齿断面究竟是否为齿柱状结构,而美洲的布氏柱门齿象(Konobelodon britti) 可能是卢氏匙门齿象(Torynobelodon loomisi)的同物异名,亚洲归入Konobelodon的种不一定是铲齿象类,可能应归为副四棱齿象(Paratetralophodon); 嵌齿象科(Gomphotheriidae)中锯齿象属(Serridentinus)可能有效,它代表了嵌齿象类中一个偏轭型化的类群,向居维叶象亚科方向演化;居维叶象亚科(Cuvieroniinae)可能仅包括居维叶象(Cuvieronius)和喙嘴象(Rhynchotherium)属,而美洲其他的短颌嵌齿象类中,脊乳齿象(Stegomastodon)有可能从铲 齿象科中的一支演化而来,南方乳齿象(Notiomastodon)则可能与中华乳齿象(Sinomastodon)相关;Sinomastodon可能起源于中国南方的竹棚上新乳齿象(Pliomastodon (?) zhupengensis),原来的属型种中间中华乳齿象(Sinomastodon intermedius)具有早出原同名,建议以它的早出异名仙台中华乳齿象(Sinomastodon sendaicus)取代S. intermedius。

submitted time 2021-07-30 From cooperative journals:《古脊椎动物学报》 Hits2795Downloads245 Comment 0

5. chinaXiv:202107.00040 [pdf]

The first description of Rhinocerotidae (Perissodactyla, Mammalia) from Xinyaozi Ravine in Shanxi, North China

DONG Wei; BAI Wei-Peng; ZHANG Li-Min
Subjects: Biology >> Zoology

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 and the studied taxa indicate an age of the early Early Pleistocene. Recent studies on the rhino material not yet described show that there are at least two species of rhinocerotids: Elasmotherium peii and Coelodonta nihowanensis. There might be a third taxon provisionally named as Stephanorhinus cf. S. kirchbergensis due to incompleteness of the specimens. Since its morphometric characters are between S. kirchbergensis and C. nihowanensis, it might be a variety of one of the two species although it is more similar to the former than the latter. In the same way, The rhino specimens from Xiashagou named as Rhinoceros sinensis (?) by Teilhard de Chardin and Piveteau (1930) might be a variety of S. kirchbergensis or C. nihowanensis. The rhinocerotids uncovered so far from the Early Pleistocene deposits in the generalized Nihewan Basin including two certain species and two uncertain ones. The localities yielding E. peii include Xiashagou, Shanshenmiaozhui, Daheigou and Xinyaozi; those yielding C. nihowanensis include Xiashagou, Danangou, Donggutuo, Shanshenmiaozhui and Xinyaozi. R. sinensis (?) appeared only at Xiashagou and Stephanorhinus cf. S. kirchbergensis only at Xinyaozi.

submitted time 2021-07-21 From cooperative journals:《古脊椎动物学报》 Hits2265Downloads246 Comment 0

6. chinaXiv:202107.00041 [pdf]

Stratigraphical significance of Ulantatal sequence (Nei Mongol, China) in refining the latest Eocene and Oligocene terrestrial regional stages

Joonas WASILJEFF; ZHANG Zhao-Qun
Subjects: Biology >> Zoology

Robust regional chronostratigraphic framework is the basis of understanding climatic and faunal events in the geologic history. One of the most dramatic faunal turnovers of the past 50 million years in Asia is linked to the Eocene–Oligocene Transition (EOT) at about 34 Ma. However, the chronostratigraphic relationships between faunal modulation and geologic events associated with the EOT in China have remained uncertain before and after the epoch boundaries, mainly due to the scarcity of continuous records and problems in correlating and subdividing the classic areas containing abundant mammalian fossils. Past decades have seen developments in establishing Chinese regional Paleogene Land Mammal Ages, and albeit many ages are well constrained, some, such as those of the latest Eocene and the Oligocene, have remained unsettled. In this paper, we present how recent evidence from the fossiliferous Ulantatal sequence, Nei Mongol, China, provides better constraints to the latest Eocene and Oligocene Chinese Land Mammal ages (Baiyinian, Ulantatalian, and Tabenbulukian). We propose Ulantatal sequence as a new regional unit stratotype section of the Ulantatalian stage, and the lower boundary of Tabenbulukian stage to be reassigned to Chron C9r (27.7 Ma), with the lowest occurrence of Sinolagomys as the marker horizon.

submitted time 2021-07-21 From cooperative journals:《古脊椎动物学报》 Hits2088Downloads272 Comment 0

7. chinaXiv:202106.00103 [pdf]

A juvenile skull of the longirostrine choristodere (Diapsida:Choristodera), Mengshanosaurus minimus gen. et sp. nov.,with comments on neochoristodere ontogeny

YUAN Meng; LI Da-Qing; Daniel T. KSEPKA; YI Hong-Yu
Subjects: Biology >> Zoology

Choristoderes were an important clade of semi-aquatic predators that occupied Laurasian freshwater ecosystems from the Middle Jurassic to the Miocene. During the Early Cretaceous, the neochoristodere lineage evolved large size and long snouts, converging on the body plan of modern crocodilians. Here, we describe a new longirostrine choristodere, Mengshanosaurus minimus gen. et sp. nov. from the Lower Cretaceous Mengyin Formation of Shandong Province, China. The holotype is the smallest reported neochoristodere individual, with a skull length of only 35 mm. The poorly ossified braincase, along with retention of a fontanel at the frontal-parietal suture, indicates this individual was a juvenile. Phylogenetic analyses recovered Mengshanosaurus as a neochoristodere, a placement supported by the presence of a single narial opening, fusion of the nasals, and expansion of the temporal fenestrae. In the Neochoristodera, Mengshanosaurus is sister to a clade consisting of Ikechosaurus, Tchoiria, Simoedosaurus, and Champsosaurus. It differs from other neochoristoderes in having the lacrimal foramen between the prefrontal and lacrimal, in addition to having large vomerine teeth (exceeding one-third the width of corresponding maxillary teeth). The closely arranged marginal teeth and large vomerine teeth suggest juvenile choristoderes may have fed on invertebrates and insects, similar to juveniles of modern crocodilians. However, the observation that very young neochoristoderes had similar skull proportions and marginal tooth shapes to adults, along with features suggesting a more fully aquatic ecology, suggest that neochoristoderes exhibited less pronounced ontogenetic niche shifts than modern crocodilians.

submitted time 2021-06-21 From cooperative journals:《古脊椎动物学报》 Hits4616Downloads438 Comment 0

8. chinaXiv:202105.00071 [pdf]

Using Bayesian tip-dating method to estimate divergence times and evolutionary rates

ZHANG Chi
Subjects: Biology >> Zoology

贝叶斯支端定年法是近些年开发的推断类群分异时间和演化速率的方法。它克服了传统分步计算的缺陷,但涉及到的统计学知识也更多。本文从贝叶斯统计计算的角度分层剖析了支端定年法的原理和计算过程,按照分异时间的先验分布、演化速率的先验分布、特征状态变化的模型和马氏链蒙特卡罗算法几个部分,叙述并讨论了定年计算中的主要模型和算法。旨在一定程度上为古生物学家分析实际数据提供参考。

submitted time 2021-05-20 From cooperative journals:《古脊椎动物学报》 Hits3794Downloads513 Comment 0

9. chinaXiv:202105.00073 [pdf]

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

REN Yi; XU Guang-Hui
Subjects: Biology >> Zoology

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.

submitted time 2021-05-20 From cooperative journals:《古脊椎动物学报》 Hits3310Downloads444 Comment 0

10. chinaXiv:202104.00005 [pdf]

Taxonomic revision of the holotype of Proboselaphus watasei Matsumoto, 1915 (Bovidae, Artiodactyla) from Chuanyu area, China

NISHIOKA Yuichiro; KOHNO Naoki; KUDO Yuichiro
Subjects: Biology >> Zoology

A taxonomic revision of Proboselaphus watasei Matsumoto, 1915 (Bovidae, Artiodactyla) from the Pleistocene of Chuanyu area, China demonstrates that this genus and species names are invalid. The holotype with a skull and mandibles was recently rediscovered in the fossil collection by Nobuo Naora, which is housed in the National Museum of Japanese History, Chiba Prefecture, Japan. Proboselaphus watasei was described as a closely-related species to living nilgai, or Boselaphus tragocamelus, in South Asia, based on general characteristics of pecorans, such as small bony horn-cores and hypsodont cheek teeth. However, the cranial and dental morphologies re-examined in the present study clearly show that the holotype has cervid-specific characteristics: e.g., the fronto-parietal surface curving dorsally, the basioccipital with a triangular outline, and molars with isolated anterior and posterior lobes. The molars of the holotype are comparable to those of Cervus unicolor, in having strong accessary structures (or spurs, cingulums/cingulids, and styles/stylids), and are as large as those of Cervus cf. C. unicolor from the Pleistocene deposits in southern China. This taxonomic change suggests that any crown-boselaphins had not dispersed into East Asia since the Pleistocene.

submitted time 2021-04-02 From cooperative journals:《古脊椎动物学报》 Hits3568Downloads558 Comment 0

12345678910  Last  Go  [179 Pages/ 1789 Totals]