关键词: 中西瓦利克; 晚中新世; 猪超科; 云南猪属; 原河猪属; 河马齿河猪属;
DOI：doi: 10.19615/j.cnki.2096-9899.231120
提交时间： 2023-11-30
摘要：描述了印度北部比拉斯布尔区喜马偕尔邦Haritalyangar地区中西瓦利克的猪类化石 上、下颌及牙齿材料。Haritalyangar地区以晚中新世动物群、古人类和其他灵长类动物的 多样性而闻名。研究材料为作者之一(ARS)在该地区多次野外季采集的猪类化石；猪类化 石地点和最近报道的长鼻类化石地点(含古猿化石地点)也被绘制在地图上。这些化石地点 广泛分布于Makkan Khad到 Sir Khad区域内的“Lower Alternations”层和“Upper Alternations” 层。猪类化石被鉴定为三个属：Propotamochoerus (P. hysudricus)、Hippopotamodon (H. sivalense) 和Yunnanochoerus (Y. dangari)。 Propotamochoerus hysudricus 为中西瓦利克最 常见的化石猪类，新发现的Yunnanochoerus dangari化石进一步证明这种古猪类化石仅在 Haritalyangar地区有少量遗存。Haritalyangar地区新发现的猪类化石组成与巴基斯坦的Nagri 动物群相近。基于猪类化石进行的的Potwar高原年代地层学对比表明，Haritalyangar地区的 “Lower Alternations”层的年龄范围为~10–9 Ma, 与最新的磁极性地层学年代范围很接近。
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关键词: Yagou; Linxia; Gansu; Late Oligocene; Jiaozigou Formation; micromammal fossils;
DOI：DOI: 10.19615/j.cnki.2096-9899.230927
提交时间： 2023-10-13
摘要：Renewed fieldwork in 2003 produced a rich micromammal assemblage from the basal part of the Jiaozigou Formation in the Yagou area of Linxia Basin. 17 genera distributed among 13 families of three orders were recovered. The micromammal fauna is a typical Oligocene assemblage for Central and Eastern Asia. 14 genera (~82% of the fauna) are common in the Oligocene of Asia. Of them four genera and four species of Eucricetodon are restricted to the Oligocene, one genus (Bagacricetodon) is restricted to Late Oligocene and Glis and Eomyodon made their first appearances in the Late Oligocene. Based on this micromammal composition, the basal part of the Jiaozigou Formation in the Yagou area could be mainly of Late Oligocene in age, which is in accordance with the conclusion based on large mammal fossils. In comparison with the other Late Oligocene micromammal faunas in Central and East Asia, the Yagou Fauna is slightly older than the Ulan III biozone of Nei Mongol and biozone C of Mongolia, because it has two Eocene genera and lacks more advanced genera. This is roughly in accordance with the recent palaeomagnetic interpretation for the Maogou section, where the lower boundary of the Jiaozigou Formation was correlated with Chron C10r (~29 Ma). The presence of large number of xerophilous zapodines, ctenodactylids, cricetids and lagomorphs combined with fossorial Tsaganomys and the lithology of the fossil-bearing deposits, composed of gypsiferous reddish brown mudstone, tend to show a semiarid woodland-shrubland habitat during the Late Oligocene in Yagou area. In Late Oligocene more frequent faunal interchange might have occurred between Asia and Europe (4 genera commonly shared) rather than between Asia and America (only 1 genus shared), partly because of the disappearance of the Turgai Strait.
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关键词: 中新世; 嵌齿象; 颌门齿象; 豕棱齿象; 长鼻类;
DOI：10.19615/j.cnki.2096-9899.230917
提交时间： 2023-09-20
摘要：间型三棱齿象(Trilophodon connexus Hopwood, 1935)长期以来被认为是中国嵌齿象属 (Gomphotherium)的一个代表种。然而，由于其下颌联合部与下门齿的形态未知，这一归入 存疑。重新研究了来自新疆准噶尔盆地北缘乌伦古河地区哈拉玛盖组的一件此前归为陕西嵌齿象相似种(Gomphotherium cf. G. shensiensis)的下颌。该下颌联合部伸长，呈深槽状， 下门齿缺失，因此确定可归入豕棱齿象科(Choerolophodontidae)。进一步将间型三棱齿象 的正型标本与其相比较，两者颊齿的关键特征完全一致，包括：高度丘型化，m3伸长， 具有四脊，上下颊齿第二脊“人字型”(chevron)很弱，第二脊中附锥与前中心小尖不愈合， 釉质褶皱、齿谷中小锥及白垩质发育弱或缺失。因此，间型三棱齿象事实上是一种豕棱齿 象类而非嵌齿象。综上所述，暂将其改定为间型“豕棱齿象” (“Choerolophodon” connexus (Hopwood, 1935))。同时，以上特征与北美的索普颌门齿象(Gnathabelodon thorpei)比较接 近。此外，在颌门齿象属和间型“豕棱齿象”中，颊齿第二脊呈“人字型”, 釉质褶皱、齿谷中 小锥及白垩质发育强这些典型的豕棱齿象属(Choerolophodon)的特征较弱甚至缺失，但m3 齿脊数变多，这表明颌门齿象属可能起源于东亚的间型“豕棱齿象”。
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1694
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185
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0
关键词: 湖南; 中泥盆统; 胴甲鱼类; 沟鳞鱼类; 系统发育; 古生物地理学; 数据可视化;
DOI：10.19615/j.cnki.2096-9899.230901
提交时间： 2023-09-05
摘要：计荣森先生于1940年基于湖南长沙附近中泥盆统跳马涧组采集到的一些以前中背片 为代表的胴甲鱼类标本命名了中华沟鳞鱼(Bothriolepis sinensis), 这是在中国正式命名的第 一种古生代脊椎动物。虽然卢立伍于1988年对后续出产于模式种产地的其他中华沟鳞鱼材 料进行了补充描述，但研究者对中华沟鳞鱼的形态学特征和系统发育仍缺乏全面认识。在 此基于计荣森先生所采集的样本及一些收藏于中国地质博物馆未正式发表的化石，对中华 沟鳞鱼进行了再研究，补充了其头部与躯甲的部分特征。与其他沟鳞鱼类相比，中华沟鳞 鱼拥有以下一系列特征：较大的听上加厚区、颅顶甲长宽比1.4–1.6、较宽的眶窗(宽于颅顶 甲的1/3)以及扇形的眶前凹等。系统发育分析结果显示，B. askinae并非位于沟鳞鱼支系的 最原始位置；中华沟鳞鱼与广东沟鳞鱼因同样拥有纤细的附肢近端(长宽比大于7)而形成了 一个稳定的单系。本研究中绝大部分的中国种类均位于同一支系上，该支系的共有衍征为 其胸鳍感觉管从第一腹中片延伸至第二腹中片。此外，基于“深骨”平台数据的古生物地理 可视化分析结果表明，沟鳞鱼类最早于艾菲尔期出现在华南与东冈瓦纳，并迅速地辐射并 扩散至全球，最终于法门期在瑞亚克洋两岸表现出了高度的物种多样性。
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3994
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0
关键词: Guizhou and Yunnan; Middle Triassic; Ionoscopiformes; Halecomorphi; osteology; phylogeny;
提交时间： 2023-07-12
摘要：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 15 new specimens. Among them, IVPP V24315 (standard length = 64 mm) is appointed as the neotype, given that the holotype is missing. 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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4230
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0
关键词: Shuitangba; Yunnan; Late Miocene; small mammals; bamboo rat;
提交时间： 2023-07-12
摘要：The Shuitangba subbasin lignite deposits of the Zhaotong Basin in northern Yunnan Province have produced vertebrate fossils of terminal Miocene age. We conducted test wet screening of fossiliferous sediment in 2014 to increase representation of small mammals. This effort produced four teeth of a very large bamboo rat, much larger than the previously known bamboo rat present at Shuitangba, and representing a new species. This new species is characterized by its molars being remarkably larger than those of other known species of Miorhizomys, and being hypsodont with cementum, and less anterorposteriorly compressed. The age of this new species from Shuitangba is in the range of 6.2 to 6.7 Ma. It appears that diverse bamboo rats of the extinct genus Miorhizomys were present in the Late Miocene of Yunnan, somewhat before the 6 Ma appearance of extant Rhizomys to the north in the vicinity of Shanxi Province.
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关键词: 邦塘组; 缅甸; 中始新世; 鲸偶蹄目; 古鼷鹿科; Paukkaungmeryx;
提交时间： 2023-05-25
摘要：描述了缅甸中部邦塘组Myaukse Kyitchaung地点原始反刍类古鼷鹿科小包康鼷鹿 (Paukkaungmeryx minutus Ducrocq et al., 2020)的牙齿新材料。新材料的上臼齿与正型标本 相比形态上仅有微小的变异，如更加发育的颊侧和舌侧齿带。下颊齿具有原始的特征， 包括：简单的p4, 下臼齿呈丘月齿型，以及下三角座后壁无“褶”状结构。新材料的发现使 Paukkaungmeryx成为邦塘发现的第二个同时保存上、下牙齿的古鼷鹿科成员，也展现了古 鼷鹿科早期演化的复杂历史。
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4676
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401
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0
关键词: China; Miocene; Mammutidae; Zygolophodon; Miomastodon;
提交时间： 2023-03-14
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.
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关键词: experimental taphonomy; chondrocytes; osteocytes; postmortem autolysis; freeze related cell-death; cellular and biomolecule fossilization; aDNA substrate;
提交时间： 2023-03-14
摘要：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 freezingthawing 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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319
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关键词: Avialae; Bohaiornithidae; cranium; cranial kinesis; Enantiornithes;
提交时间： 2023-02-17
摘要：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 twodimensions. This complicates 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 threedimensional 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 reinforcing the recent hypothesis that the temporal and palatal regions are evolutionarily conservative and that the akinetic skull has been conserved well into of early branching avialans.
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