分类： 生物学 >> 动物学 提交时间： 2023-03-14 合作期刊: 《古脊椎动物学报》
摘要： 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In the present paper, we restudied the previously published zygodont specimens of the gracile type, as well as several unpublished Mammutidae specimens.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 Several unpublished specimens from Hezheng, Gansu, Tunggur, Nei Mongol, Tongxin, Ningxia and Junggar, Xinjiang exhibit a lower degree of zygodonty, corresponding to the robust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.
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.
分类： 生物学 >> 动物学 提交时间： 2021-07-30 合作期刊: 《古脊椎动物学报》
摘要： 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。
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： 地球科学 >> 地质学 提交时间： 2017-11-24 合作期刊: 《古脊椎动物学报》
摘要： Reconstructing the diet of extinct species is a fundamental goal in vertebrate paleobiology. Dental calculus is the calcium phosphate deposits on teeth, which captures a large number of food particles and contains the food information of ancient animal. It is possible to explore ancient animal dietary and investigate the environmental information from dental calculus. A large number of starch granules were found in dental calculus of Dicros gansuensis excavated from the earliest Late Miocene Guonigou fauna of the Linxia Basin, Gansu Province. It is the first time that starch granules from Late Miocene were found. We classified the ancient starch granules by its morphological characteristics and also analyzed the starch granules of leaves of modern plants around the living environment of D. gansuensis to find modern starch granules and compare them with ancient ones. The results indicate that D. gansuensis may eat not only shrubs leaves, such as the plant from Caprifoliaceae, but also some tree leaves from Juglandaceae (walnut), and maybe some herbs from Ranunculaceae and Polygonaceae. It is consistent with the results of previous morphological studies, and it also provides more information. Our study extends the range of time and object for dental calculus research, and offers more possibilities for research on feeding habits of ancient mammals.
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： A new skull of Urmiatherium intermedium (Bovidae, Artiodactyla) from the Linxia Basin, Gansu Province is described here. U. intermedium is a large Late Miocene bovid with an odd-looking horn apparatus, consisting of a pair of degenerate, closely situated horn-cores, and a large area of exostoses on the frontal and the parietal bones. Plenty of skulls, teeth, and bone fragments of U. intermedium have been reported from North China, but the skull to be described is the first discovery from the Linxia Basin, expanding the geographic distribution of U. intermedium to the northeast edge of the Tibetan Plateau. Although Urmiatherium is generally thought to be closely related to Plesiaddax, Hezhengia, Tsaidamotherium, and some other Late Miocene “ovibovines”, the phylogenetic position of Urmiatherium is still in debate. The distribution of Urmiatherium is wide, spanning from Iran to North China. Urmiatherium seldom accompanies with other Late Miocene “ovibovines” in North China, but is accompanied by other bovids like Sinotragus.
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： Mammut is the terminal taxon of the proboscidean group Mammutidae, which survived to the Late Pleistocene. Although this genus was widely distributed in the Pliocene of Eurasia and the Pleistocene of North America, little is known about its early evolution. Here, we report on Mammut cf. M. obliquelophus from the Upper Miocene of northern China based on new fossil material, including an almost complete juvenile cranium and other remains, which show many primitive features within Mammutidae and clearly demonstrate the morphological evolution of Mammut. The strongly laterally expanded lateral wing of the occiput and the presence of basal constriction of the incisive fossa display cranial similarity between Mammut cf. M. obliquelophus and both Eozygodon morotoensis and Choerolophodon guangheensis, early representatives of the Mammutidae and Choerolophodontidae, respectively, indicating the close relationship between these two groups: both of them are located at the basal phylogenetic positions in Elephantimorpha. This result is further confirmed by a cladistic analysis.
分类： 地球科学 >> 地质学 提交时间： 2017-08-11 合作期刊: 《古脊椎动物学报》
摘要： A new skull of Urmiatherium intermedium (Bovidae, Artiodactyla) from the Linxia Basin, Gansu Province is described here. U. intermedium is a large Late Miocene bovid with an odd-looking horn apparatus, consisting of a pair of degenerate, closely situated horn-cores, and a large area of exostoses on the frontal and the parietal bones. Plenty of skulls, teeth, and bone fragments of U. intermedium have been reported from North China, but the skull to be described is the first discovery from the Linxia Basin, expanding the geographic distribution of U. intermedium to the northeast edge of the Tibetan Plateau. Although Urmiatherium is generally thought to be closely related to Plesiaddax, Hezhengia, Tsaidamotherium, and some other Late Miocene “ovibovines”, the phylogenetic position of Urmiatherium is still in debate. The distribution of Urmiatherium is wide, spanning from Iran to North China. Urmiatherium seldom accompanies with other Late Miocene “ovibovines” in North China, but is accompanied by other bovids like Sinotragus. 报道并描述了一件来自甘肃临夏盆地的中间乌米兽(Urmiatherium intermedium)头骨化石新材料，该材料产自柳树组上部，属于晚中新世晚期杨家山动物群。中间乌米兽是一种大型的晚中新世牛科动物，角心特化，短且呈薄板状，并且在基部相互靠近。在角心前后方的额骨和顶骨上，发育大片赘生骨疣，这些骨疣与角心一起，合称角器。20世纪初，步林报道了中国北方晚中新世地层中的大量中间乌米兽化石，包括产自山西保德和甘肃庆阳的二十多件头骨以及很多破碎的齿列和骨骼。本文报道的乌米兽头骨化石是乌米兽在甘肃临夏盆地的首次发现，将其在中国北方的分布向西扩展到了青藏高原东北缘地带。乌米兽被普遍认为与近旋角羊(Plesiaddax)、和政羊(Hezhengia)和柴达木兽(Tsaidamotherium)等晚中新世“麝牛类”牛科动物具有较近的亲缘关系，但其系统发育地位仍存有争议。相比其他晚中新世“麝牛类”牛科动物，乌米兽的分布较广，从伊朗至中国北方都有分布，但它鲜与其他晚中新世“麝牛类”牛科动物伴生。在临夏盆地，与其伴生的牛科动物目前仅发现中华羚(Sinotragus)一种。
分类： 地球科学 >> 地质学 提交时间： 2017-08-08 合作期刊: 《古脊椎动物学报》
摘要： Mammut is the terminal taxon of the proboscidean group Mammutidae, which survived to the Late Pleistocene. Although this genus was widely distributed in the Pliocene of Eurasia and the Pleistocene of North America, little is known about its early evolution. Here, we report on Mammut cf. M. obliquelophus from the Upper Miocene of northern China based on new fossil material, including an almost complete juvenile cranium and other remains, which show many primitive features within Mammutidae and clearly demonstrate the morphological evolution of Mammut. The strongly laterally expanded lateral wing of the occiput and the presence of basal constriction of the incisive fossa display cranial similarity between Mammut cf. M. obliquelophus and both Eozygodon morotoensis and Choerolophodon guangheensis, early representatives of the Mammutidae and Choerolophodontidae, respectively, indicating the close relationship between these two groups: both of them are located at the basal phylogenetic positions in Elephantimorpha.This result is further confrmed by a cladistic analysis.
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