三叶虫是古生代海洋中最引人注目的节肢动物之一,其外骨骼具有极高的多样性。相较于易于保存的矿化外骨骼,三叶虫的软躯体构造往往难以在化石记录中保存,这增加了三叶虫内部构造解剖和演化的研究难度。寒武纪布尔吉斯页岩型特异埋藏化...三叶虫是古生代海洋中最引人注目的节肢动物之一,其外骨骼具有极高的多样性。相较于易于保存的矿化外骨骼,三叶虫的软躯体构造往往难以在化石记录中保存,这增加了三叶虫内部构造解剖和演化的研究难度。寒武纪布尔吉斯页岩型特异埋藏化石群中独特的保存条件使得三叶虫精细的软躯体构造得以保存,为解析三叶虫内部构造提供了材料。本文描述了来自云南昆明呈贡下庄剖面寒武系第二统第三阶红井哨组泥岩中产出的云南马龙头虫(Malongocephalus yunnanensis Zhang and Lin in Zhang et al.,1980)的软躯体构造。标本展示了M. yunnanensis的触角至少有13个肢节,触角后附肢具有板片状的外肢。消化道分化为前肠、中肠和后肠,头部见三对消化腺。这是莱德利基虫目(Redlichiida)小阿贝得虫科(Abadiellidae)中软躯体构造的首次报道,丰富了寒武纪早期三叶虫的解剖学信息。本研究比较分析了莱德利基虫目的触角相对长度差异,对三叶虫的消化系统构造进行了讨论。展开更多
Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the le...Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the left ilium, left pubis, anterior caudals, most of the dorsal ribs and distal end of the left femur. Fusuisaurus zhaoi is diagnosed by a unique combination of character states among the known sauropods. It displays several synapomorphies of Titanosauriformes but lacks many derived features seen in other titanosauriforms, suggesting that the new taxon represents the basalmost known titanosauriform and providing new evidence that Titanosauriformes originated from Asia. A size comparison suggests that Fusuisaurus zhaoi is among the largest Early Cretaceous sauropods, providing an important addition to the Early Cretaceous Chinese sauropod diversity.展开更多
The taxonomic identification of Quaternary remains requires a comparison of fossil bones with the skeletons of existing taxa based on the morphological criteria. However, the osteology of most modern snake species has...The taxonomic identification of Quaternary remains requires a comparison of fossil bones with the skeletons of existing taxa based on the morphological criteria. However, the osteology of most modern snake species has not yet been studied. This work is aimed at finding differences in the bone morphology of Amur and Dione’s ratsnakes and the criteria for their identification. The variety of bone morphology depends on several parameters. First, these are species differences which determine the systematic position of the animal. Second, it is individual varia bility.Third, these are progressive changes in the vertebrae morphology along the vertebral column from the first vertebra to the last. Fourth, it is age-related variability. 20 skeletonised specimens: 12 specimens of Elaphe dione and 8 specimens of Elaphe schrenckii were used to define diagnostic osteological characters. The bones of the two studied species are very similar and their variability overlaps. However, differences and identification criteria were found for 13 skull bones:nasal, frontal, parietal, supraoccipital, maxilla, quadrate,palatine, pterygoid, ectopterygoid, basiparasphenoid,basioccipital, dentary and the compound bone. In addition, the variability and differences of the cervical,trunk, cloacal, and caudal vertebrae were examined.展开更多
Objective Limnocythere inopinata(Baird,1843)is an ostracod widely distributed in recent non-marine waters and in Quaternary sediments,where it comprises various phenotypes(Yin et al.,1999;Zhang et al.,2015).Based on t...Objective Limnocythere inopinata(Baird,1843)is an ostracod widely distributed in recent non-marine waters and in Quaternary sediments,where it comprises various phenotypes(Yin et al.,1999;Zhang et al.,2015).Based on the nodation patterns,five phenotypes were described in previous publications,namely,the unnoded,the phenotype with one node in the postero-ventral part of the valve,one with two nodes in the antero-ventral and postero-ventral parts of the valve,another with three nodes in the antero-ventral,postero-ventral and postero-dorsal parts of the valve.展开更多
文摘三叶虫是古生代海洋中最引人注目的节肢动物之一,其外骨骼具有极高的多样性。相较于易于保存的矿化外骨骼,三叶虫的软躯体构造往往难以在化石记录中保存,这增加了三叶虫内部构造解剖和演化的研究难度。寒武纪布尔吉斯页岩型特异埋藏化石群中独特的保存条件使得三叶虫精细的软躯体构造得以保存,为解析三叶虫内部构造提供了材料。本文描述了来自云南昆明呈贡下庄剖面寒武系第二统第三阶红井哨组泥岩中产出的云南马龙头虫(Malongocephalus yunnanensis Zhang and Lin in Zhang et al.,1980)的软躯体构造。标本展示了M. yunnanensis的触角至少有13个肢节,触角后附肢具有板片状的外肢。消化道分化为前肠、中肠和后肠,头部见三对消化腺。这是莱德利基虫目(Redlichiida)小阿贝得虫科(Abadiellidae)中软躯体构造的首次报道,丰富了寒武纪早期三叶虫的解剖学信息。本研究比较分析了莱德利基虫目的触角相对长度差异,对三叶虫的消化系统构造进行了讨论。
文摘Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the left ilium, left pubis, anterior caudals, most of the dorsal ribs and distal end of the left femur. Fusuisaurus zhaoi is diagnosed by a unique combination of character states among the known sauropods. It displays several synapomorphies of Titanosauriformes but lacks many derived features seen in other titanosauriforms, suggesting that the new taxon represents the basalmost known titanosauriform and providing new evidence that Titanosauriformes originated from Asia. A size comparison suggests that Fusuisaurus zhaoi is among the largest Early Cretaceous sauropods, providing an important addition to the Early Cretaceous Chinese sauropod diversity.
文摘The taxonomic identification of Quaternary remains requires a comparison of fossil bones with the skeletons of existing taxa based on the morphological criteria. However, the osteology of most modern snake species has not yet been studied. This work is aimed at finding differences in the bone morphology of Amur and Dione’s ratsnakes and the criteria for their identification. The variety of bone morphology depends on several parameters. First, these are species differences which determine the systematic position of the animal. Second, it is individual varia bility.Third, these are progressive changes in the vertebrae morphology along the vertebral column from the first vertebra to the last. Fourth, it is age-related variability. 20 skeletonised specimens: 12 specimens of Elaphe dione and 8 specimens of Elaphe schrenckii were used to define diagnostic osteological characters. The bones of the two studied species are very similar and their variability overlaps. However, differences and identification criteria were found for 13 skull bones:nasal, frontal, parietal, supraoccipital, maxilla, quadrate,palatine, pterygoid, ectopterygoid, basiparasphenoid,basioccipital, dentary and the compound bone. In addition, the variability and differences of the cervical,trunk, cloacal, and caudal vertebrae were examined.
基金financially supported by the National Nature Sciences Foundation of China(Grant No.41807420)China Geological Survey(Grant No.12101106000150093)the Basic Research Foundation of the Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences(Grant No.SK201705)。
文摘Objective Limnocythere inopinata(Baird,1843)is an ostracod widely distributed in recent non-marine waters and in Quaternary sediments,where it comprises various phenotypes(Yin et al.,1999;Zhang et al.,2015).Based on the nodation patterns,five phenotypes were described in previous publications,namely,the unnoded,the phenotype with one node in the postero-ventral part of the valve,one with two nodes in the antero-ventral and postero-ventral parts of the valve,another with three nodes in the antero-ventral,postero-ventral and postero-dorsal parts of the valve.
