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： 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.
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： A skull with mandible and several cervicals of a new species of Huerzelerimys, H.asiaticus, collected from the Late Miocene Liushu Formation in Linxia Basin, Gansu Province,is described in this paper. The skull is the first one ever found for the genus Huerzelerimys. Its main characters are: size small; skull broad and short with stout rostrum; interorbital roof narrow;premaxillary laterodorsal crest well developed; frontal crests weak and subparallel; incisive foramina long, with their posterior ends lined up with anterior root of M1; posterior palatal foramina located mesial to M2; caudal border of hard palate lying posterior to M3;interpterygoid foramen absent; alisphenoid canal bony; bulla large and inflated; internal carotid foramen located near the basilar tubercle; mandible having low horizontal ramus and deeply concave diastema; anterior end of masseteric ridge lined up with anterior margin of m1; mental foramen situated slightly anterior to masseteric ridge and anteroventral to m1, near to mandibular diastema; upper incisors orthodont; M1 having slightly anteriorly located t1; in M1 and M2 t6 and t9 connected by distinct crest and t12 crest-like; t1 and t3 of M2 and t1 of M3 connected to t5; M3 having t3 and a large isolated t8; small Acc of m1 connected with both Alc and Abc; m1 and m2 having distinct buccal cingula, larger c2 attached to protoconid, and low crest-like posterior heel; m2 and m3 having isolated Abc; c1 absent in m3. The evolutionary level of the described skull tends to show that the age of the upper part of the Liushu Formation yielding H. asiaticus may belong to late Bahean, corresponding to European upper MN11 or lower MN12.
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： Specimens reported in this note represent the first discovery of Yuomys in Altun Shan. A new species, Yuomys altunensis, is established based on the following features: molars large and wide in proportion; metaconule distinctly separated from metacone, metaloph long, but incomplete; hypocone smaller than protocone; sinus extending to base of crown on lingual side; postcingulum connectting lingual side of metacone; metacone crescent and postcingulum short in M3. Yuomys altunensis is similar to Y. cavioides, Y. eleganes and Y. huangzhuangensis of late Middle Eocene in molar morphlogy. According to its evolutionary level, Y. altunensis is supposed as of late Middle Eocene in age, or slightly later.
分类： 地球科学 >> 地质学 提交时间： 2017-09-28 合作期刊: 《古脊椎动物学报》
MAO Fang-Yuan
LI Chuan-Kui
MENG Jin
LI Qian
BAI Bin
WANG Yuan-Qing
ZHANG Zhao-Qun
ZHAO Ling-Xia
WANG Ban-Yue
摘要： Tooth enamel is composed of elongated, hexagonal crystallites of hydroxyapatite. Some crystallites are arranged into various regual structures and futher formed a composite structure in a hierarchical manner. The hierarchical system can provide a basis for analysis different levels of structural complexity from varitaiton of particular crystallite strucutes to variation of structural types throughout a individual’s dentition. The size, orientation, distribution and the packing patterns of crystallites are gene-comtrolled and have limited range of intraspecific variability. Thus, these microstructures provide considerable and reliable morphological characters that help understanding of external dental morphology in context of both phylogeny and function in vertebrates. Because teeth are highly resistant to weathering, mainly owing to their enamel covering, so that they were commonly preserved as fossils. This organic system, particularly their microstructures, has attracted more and more attention from vertebrate paleontologists and other morphologists. However, as already recognized by many previous studies, some terminologies of the enamel microstructures have been complex and used inconsistently. Although considerable effort has been made to study enamel microstructures in China during the last few decades, a standard terminology of enamel microstructures in Chinese has not be formally brought into line with that in English literatures. Here we intend to introduce and systematize the relevant terminology used in the study of enamel microstructures and translate them into Chinese, in hoping that this systematic effort will enhance researches of enamel microstructures in China. 脊椎动物牙齿釉质显微结构具丰富的形态学特征，承载着系统发育和生物力学等方面的信息。本文在前人的研究基础上，试图系统地介绍牙釉质显微结构的基本内容，提出牙釉质研究中相关术语的中文译名建议，并对一些重要术语做了简要解释，供相关研究者参考，以期促进牙釉质显微结构研究的进一步发展。
分类： 地球科学 >> 地质学 提交时间： 2017-08-02 合作期刊: 《古脊椎动物学报》
摘要： Specimens reported in this note represent the frst discovery of Yuomys in Altun Shan. A new species, Yuomys altunensis, is established based on the following features: molars large and wide in proportion; metaconule distinctly separated from metacone, metaloph long, but incomplete; hypocone smaller than protocone; sinus extending to base of crown on lingual side; postcingulum connectting lingual side of metacone; metacone crescent and postcingulum short in M3. Yuomys altunensis is similar to Y. cavioides, Y. eleganes and Y. huangzhuangensis of late Middle Eocene in molar morphlogy. According to its evolutionary level, Y. altunensis is supposed as of late Middle Eocene in age, or slightly later. 记述了在新疆巴音郭楞蒙古族自治州若羌县阿尔金山地区彩虹沟首次发现的豫鼠一新种：阿尔金豫鼠(Yuomys altunensis sp. nov.)。其主要特征是臼齿的尺寸较大，比例上较宽，齿冠较高，臼齿的后小尖与后尖明显分开，后脊相对较长，但不完全，次尖明显小于原尖，舌侧内凹伸达臼齿齿冠基部，后齿带与后尖舌侧连； M3后尖为新月形，后齿带较短等。根据豫鼠臼齿的进化趋势和新种臼齿的尺寸较大、齿冠较高和舌侧内凹伸达齿冠基部的特征与Y. cavioides, Y. eleganes和Y. huangzhuangensis相近，但颊齿比例较宽判断 Y.altunensis可能与该3种处于同样的进化阶段或稍进步。其产出的地层时代很可能与它们相近或稍晚，即为晚中始新世或稍晚
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