贵州关岭上三叠统的楯齿龙类化石

记述的新铺中国豆齿龙（Sinocyamodus xinpuensis gen. et sp. nov.）代表了齿龙目的一新属。这是齿龙类化石在我国的首次发现,也是这类特殊的海生爬行动物在欧洲、北非和中东以外地区的首次记录。标本产自贵州关岭晚三叠世瓦窑组一段的泥晶灰岩中,与鱼龙类、幻龙类及海龙类等多种海生爬行类同时产出。这一化石组合表明,贵州关岭三叠纪海生爬行动物群的性质与西特提斯动物群（wstern-Tethyan fauna）的性质极为相似,这两个地区在晚三叠世早期有广泛的动物交流。     

中国三叠纪海生爬行动物化石研究的回顾与进展

中国三叠纪海生爬行动物化石研究始于20世纪50年代,近10年来取得了重要的进展。此类化石在华南分布广泛,已见于多个省区的十余处地点,涉及自下三叠统奥伦尼克阶至上三叠统诺利阶的至少7个层位,并显示出由东向西产出层位逐渐升高的趋势。我国的三叠纪海生爬行动物化石门类齐全,属种丰富,已知类群包括鱼龙类、海龙类、檐齿龙类、始鳍龙类、原龙类、初龙类和湖北鳄类,显示出典型的西特提斯动物群特征,同时也体现了与东太平洋动物群的某些联系,以及一定的地方色彩。这些化石为研究三叠纪海生爬行动物各个类群的起源、演化和绝灭以及海洋环境的变迁提供了新的材料。     

藏南泽当雅鲁藏布缝合带中的三叠纪放射虫

西藏南部泽当西金鲁村附近发现的一套硅质岩含有两个放射虫化石组合：Capnuchosphaera triassica组合和Pseudostylosphaera nazaroui组合。这些放射虫化石可以同中三叠世拉丁期至晚三叠世卡尼期放射虫动物群对比,这套硅质岩为一外为岩体,包括在由高劈理化泥岩组成的混杂岩基质中,这是雅鲁藏布江缝合带三叠纪放射虫的首次报道。     

湖北三叠纪海生爬行动物的层位及时代

通过对化石点的实地调查证实 ,湖北南漳、远安发现的海生爬行类除孙氏南漳龙 (大冶组顶部或嘉陵江组底部 )外都产自嘉陵江组 ,它们的时代同为早三叠世奥伦尼克期。由孙氏南漳龙、南漳湖北鳄、湖北汉江蜥和远安贵州龙形成的这一海生爬行动物组合 ,是上扬子地区层位最低的 ,生存时代早于其他海生爬行动物组合。与产自欧洲的肿肋龙类有密切亲缘关系的贵州龙和汉江蜥 ,是该科最早的代表 ,也是鳍龙类最早的代表之一 ,为探讨鳍龙类和肿肋龙类的起源及传播提供了新的证据。     

中国三叠纪鱼类综述

三叠纪鱼类在中国分布广泛。与当时“南海北陆”的古地理格局一致,淡水鱼类主要分布于北方大陆的河湖相盆地,但也见于扬子板块与北方大陆碰撞后的四川盆地;海生鱼类则主要分布于华南和喜马拉雅地区。值得注意的是,鄂尔多斯盆地已知的三叠纪鱼类中,多数为海生类型或与海生鱼类密切相关。中国的淡水三叠纪鱼群主要由原始辐鳍鱼类组成,它们与西伯利亚和中亚的鱼群最为相近,但也有与劳业大陆其他地区及冈瓦纳大陆的鱼类相似的属种。海生鱼群则以“亚全骨鱼类”为主,并包含鲱亚部的进步类群和真骨鱼类的基干类型。华南扬子区拉丁至卡尼早期的鱼群远较早三叠世的鱼群丰富,且这一时期的鱼群与西特提斯同期的鱼群关系已极为密切,约有1/3的种类可归入相同的属。华南中下扬子区很可能是部分后来繁盛于特提斯区的三叠纪鱼类的发源地,如龙鱼类。中国的三叠纪鱼类虽然十分丰富,但大多已知鱼类仅限于零星发现和初步报道,因而仍有待全面深入的调查研究。     

论广西武鸣三叠纪海生爬行动物东方广西龙(鳍龙类)的时代

广西武鸣产出广西地区迄今唯一一件三叠纪海生爬行动物化石——东方广西龙(Kwangsisaurus orientalis)。受限于20世纪50年代研究条件,有关该化石产出地点、地层层位和时代信息一直比较模糊,对后人阐述中国三叠纪海生爬行动物演化过程及探究鳍龙类在华南的古地理迁移历史造成了一定阻碍。本文从岩石地层学和生物地层学入手,结合高精度同位素年代学定年结果,对武鸣地区早、中三叠世地层进行了综合分析,着重研究了含东方广西龙地层的岩性组合、生物群面貌及地层时代。东方广西龙产于板纳组薄层泥晶灰岩中,伴生有丰富的菊石化石,所属地层时代为中三叠世安尼期。对含东方广西龙地层上部层状凝灰岩中具有岩浆韵律的锆石进行了SIMS原位U-Pb年代学测试,获得了(244.2±0.7)Ma的绝对年龄值,时代相当于安尼期中晚期。东方广西龙时代的厘定排除了鳍龙类早三叠纪世晚期在下扬子区和右江盆地同时出现的原有结论,同时同位素年代学新证据证实广西武鸣海生爬行动物化石与贵州盘县海生爬行动物群基本同期,表明了鳍龙类在华南东部起源后在三叠纪中期向西南地区辐射扩散范围的广阔性和适应环境的多样性。     

关岭及相关生物群沉积与生态环境的探讨

根据近年来对黔东南至滇东关岭、兴义、贞丰和罗平等地中一晚三叠世含海生爬行动物骨架和(或)深水海百合黑色岩系(通常所称黑色页岩)化石库的研究,现将该区岩石地层单位划分.以及这些黑色岩系化石库生物组合特征、时代、分布、沉积和古地理环境概括如下:1)在关岭-兴义地区中-晚三叠世(安尼期、拉丁期和早卡尼期)地层中,至少夹有3层、甚至4层含海生爬行动物的黑色岩系化石库(或黑色"页岩"化石库),自下而上产盘县生物群、兴义生物群和关岭生物群.云南罗平地区中三叠统关岭组中新发现的"罗平生物群"与盘县生物群层位大致相当.贞丰龙场赖石科组上部新挖掘出的30m厚产创口海百合、双壳类及菊石的黑色岩系,应该是研究地区最高层位的海相三叠纪黑色岩系,时代似属晚三叠世早卡尼期晚期;2)推测这些含海生爬行动物骨架的黑色岩系化石库是在印支造山运动影响下,伴随南盘江前陆盆地隆升和闭合,在扬子克拉通台地边缘所形成的一个或几个边缘凹陷、或边缘盆地之中形成的,这些凹陷或盆地形成之初,表层水充氧,且具有很好的食物链结构,有利于各类海生生物生活;后来的海平面上升至最大海泛期,以及由此引起缺氧和含硫化氢水位的上升,导致这些凹陷逐渐变成安静、滞流的死亡之海和黑色岩系化石库;3)关岭生物群产于晚三叠世卡尼期早期小凹组下段上部黑色岩系之中,是一个典型的在滞流、缺氧且海底没有食腐动物边缘局限盆地中所形成的黑色页岩化石库,以产大量海生爬行动物和深水假浮游海百合为特征,此外还有个别的两栖类和原始龟类发现;4)产于竹杆坡组近底部黑色岩系中的兴义生物群,以产大量肿肋龙类为特点,尤以个体较小的贵州龙最为常见,共生的还有多种鱼类化石,在生物组合和产出层位上,可与阿尔卑斯南部Meride灰岩所夹黑色含沥青页岩化石库对比,时代似应归属拉丁期早或中期;大量米虾在竹杆坡组近底部含贵州龙层的发现.推测兴义生物群可能形成于台地边缘早期并不缺氧,且具有理想食物链结构的浅水、超盐的凹陷或盆地之中.由于存在浮游生物-虾-贵州龙-欧龙-虾-浮游生物所组成的生态组合和食物链结构,从而为解释以肿肋龙类为代表的兴义生物群的繁衍和多生提供了依据;接踵而来的沉积速率下降和缺氧水位的上升,以及间歇性火山作用,导致该特有生态体系的崩溃和化石库的形成.根据对贞丰挽澜竹杆坡组底部首次发现的棘皮动物的化石库的研究,指出该化石库系由海星、细小蛇尾、底栖海百合茎、海胆和海参等5类棘皮动物化石和含贵州龙骨架碎片组成,其下为8m厚夹有薄层的骨层的凝缩层沉积,后者位于硬底之上.此种沉积和埋藏模式与德国上壳灰岩早拉丁期的棘皮动物化石库类似,是在近岸海水不太浅的内陆棚的环境下,由于风暴潮作用所形成的化石库,他们与在滞流、缺氧海底、通过化石聚集所形成的化石库是不同的;5)产盘县生物群的黑色岩系化石库主要见于盘县羊件和普安青山中三叠世(安尼期)关岭组中,与云南罗平地区的"罗平生物群"在层位及生物组合上大致相当,均以含大量混鱼龙、幻龙和欧龙.以及鱼类为特点,共生的还有大量节肢动物.所不同的是后者由于靠近滨岸,故而出现大量幼年期的鱼类以及虾类和鲎类化石,推测他们形成于靠近古陆或滨岸的台缘浅水表层充氧的正常、且有时超盐的凹陷之中,时代上早于阿尔卑斯南部安尼期/拉丁期比塞娄组;其集群死亡除因后期盆地滞流、缺氧外,可能还与风暴和火山作用有关.     

贵州兴义中三叠世拉丁期兴义动物群粪化石

粪化石是重要的遗迹化石,其内含物信息可为讨论生物行为、生理、相互关系、古环境等提供重要证据,进而对恢复和重建地质历史时期的生态系统等有重要意义。本文首次报道了贵州省兴义市泥麦古剖面中三叠世拉丁期兴义动物群化石层第35自然层的7种不同形态的粪化石。通过观察粪化石的内含物情况,发现其主要由贵州龙骨骼和鱼鳞组成,极少含有无脊椎动物碎片,表明粪化石来源于非壳食性的肉食性动物。依据粪化石的尺寸、缺少螺旋结构及相对较小的内含物碎片等信息,排除动物源是无脊椎动物、大型肉食性鱼类及大型鱼龙类的可能。结合兴义动物群下部化石组合海生爬行类实体化石的信息,进一步推断所研究粪化石的动物源应为非鱼龙的海生爬行动物,很可能是幻龙类、鸥龙类或海龙类。本文报道的7种形态的粪化石显示该下部化石层中的海生爬行动物之间至少存在1级营养等级的差异,这为恢复和重建中三叠世拉丁期海洋生态系统提供了重要依据。另外微生物的参与及泥质含量较高的厌氧环境使得该层的粪化石保存完好。     

华南东部晚三叠世和早侏罗世双壳类材料及其时代意义北大核心CSCD

华南东部地区晚三叠世—早侏罗世海陆交互相地层中的半咸水-海相双壳类,对于我国广泛分布的陆相上三叠统和下侏罗统的划分具有重要的意义。文中系统描述了该区晚三叠世和早侏罗世双壳类19属29种,其中Trigonucula sakawana Ichikawa,1949,Pteria sturi(Bittner,1895),Costigervillia minima Wen,1979和Cercomyapraecursor Quenstedt,1856为首次在这一区域报道;并根据新材料将前人报道的Isocardioides Fan,1962修订为Schafhaeutlia Cossmann,1897。综合这些材料和前人研究将该区小水组、三家冲组和金鸡组双壳类分别划为以下三个组合带,即Palaeopharus-Trigonucula组合带、Bakevelloides-Jiangxiella组合带和Parainoceramus-Ryderia guangdongensis组合带。文中通过对上述组合中代表属种在区域上的时代延限的分析,认为PalaeopharusTrigonucula带和Bakevelloides-Jiangxiella带的时代限于晚三叠世卡尼期(Carnian),可能延至诺利期(Norian)早期;Parainoceramus-Ryderia guangdongensis带的时代主要为早侏罗世辛涅缪尔期(Sinemurian),可能下延至赫塘期(Hettangian),上延至土阿辛期(Toarcian)。     

广西凤山、西林等地中三叠统上部双壳类分带研究*

讨论广西西部中三叠统上部的双壳类生物地层序列,建立5个化石带;并附述黔南和滇东南晚三叠世1个双壳类带.这些带自下而上为:(1) Daonella (Longidaonella) producta-D. americana 带,属晚安尼早中期;(2) D. moussoni 高峰带,属晚安尼晚期;(3) D. rieberi-D. indica 带,属早拉丁期;(4) D. kotoi-D. jilongensis 带,属晚拉丁早期;(5) Halobia subcomata-D. varifurcata带,属晚拉丁晚期;(6) H. rugosoides-H. bifurcata 带,属早卡尼期.文内简要描述了各带的主要标志化石23种.     

PROBLEMS OF THE ORIGIN OF REPTILES

The fossil records of the four living reptilian orders can be traced into the Triassic. The earlier ancestry of the turtles has not been established. Squamates and rhyncho-cephalians evolved from the Late Permian eosuchians; crocodiles from the thecodonts. The ancestry of the eosuchians and thecodonts is to be found in the central stock of Permo-Carboniferous reptiles, the captorhinomorphs. The earliest captorhino-morphs, from the Lower Pennsylvanian, are already fully developed reptiles. The limnoscelids and solenodonsaurids are more primitive forms, retaining features typical of anthracosaurian amphibians. Neither reptiles nor any appropriate ancestors are known prior to the Lower Pennsylvanian. Because of the absence of any true ancestors, the nature of the amphibian-reptilian transition must be studied on the basis of amphibians contemporary with the early reptiles. The Permian seymouriamorphs have long been accepted as relicts of the group which gave rise to reptiles, although Seymouria itself is specialized in many features of its anatomy. The Middle Pennsylvanian genus Gephyrostegus appears to resemble much more closely the anatomy expected in the ancestors of reptiles. This genus forms the basis for consideration of the anatomical, physiological and behavioural changes which culminated in the origin of reptiles. Study of the earliest known reptiles and their closest relatives among contemporary amphibians indicates that the initial adaptation leading to the emergence of the class was assumption of a terrestrial habit, with accompanying small body size. The small body size of the immediate ancestors of reptiles would have made it possible for them to produce sufficiently small eggs that they could develop in damp places on land without initially being supported and protected by extraembryonic membranes. The rapid increase in body size in all lineages of Pennsylvanian reptiles indicates the prior development of an amniotic egg. Fundamental to the emergence of reptiles was modification in the jaw mechanism from the kinetic inertial system of amphibians to a static pressure system. The latter was presumably developed in order for the developing reptiles to utilize more active terrestrial prey. This change in the jaw mechanism is reflected in the reorganization of the palate which serves as a morphological basis for denning the establishment of reptilian status. At approximately the same stage as the change in palatal structure, the definitive reptilian vertebral pattern was developed. The apparent closure of the otic notch and the probable reorientation of the stapes in the amphibian-reptilian transition presumably resulted from the decrease in relative skull size and do not appear to be related to any change in hearing ability. The tympanum probably maintained the same relative relationship with the squamosal and supratemporal throughout this transition. On the basis of the present fossil record, all adequately known Palaeozoic reptiles appear to have had a common ancestry among the predecessors of the known gephyro-stegids. The family Diadectidae is the only important group whose specific relationships cannot be established. On the basis of this study, the following taxonomic changes are suggested: the family Limnoscelidae should not be included among the captorhinomorphs. The seymouria-morph concept should be restricted to forms having the specializations of Seymouria, the discosauriscids and kotlassids. Gephyrostegids should be specifically excluded from the Seymouriamorpha and should be included in a separate taxon among the anthra-cosaurs of equal rank with embolomeres and seymouriamorphs.     

华北铜川组爬行动物化石的首次发现及其地层意义

１９９２年,中国科学院古脊椎动物与古人类研究所从人民来信中得知,在山西永和县桑壁镇附近的河沟中发现了陆生四足动物化石。不久古脊椎所的专业人员就到化石产地进行了实地调查,并发掘出了几具保存较好的爬行动物化石。化石保存在坚硬的细砂岩中,已经修理出其中一个头骨（如图１所示）。经初步鉴定,这批化石是一类初龙形类动物,与产自新疆吐鲁番盆地中三叠世克拉玛依组的达板吐鲁番鳄（Ｔｕｒｆａｎｏｓｕｃｈｕｓｄａｂａｎｅｎｓｉｓ）（Ｙｏｕｎｓ,１９７３）关系较近,但是其内颈动脉孔位于基蝶骨侧面,而不是位于腹面,这表明…     

Figures sédimentaireset traces d'origine biologique du Trias moyen de la bordure orientale du Massif Central signification sédimentologique et paléoécologique

The sandstones with foot-prints of reptiles and saltcasts from the Middle Triassic of the eastern border of the Massif Central (France) show a striking reptilian ichnofauna. The numerous sedimentary figures and trace fossils which are described here allow to deduce the following characteristics of the depositional environment: shallow water, lower flow regime, periodical increase of salinity. The reptiles used to pass through that environment where numerous stretches of water alternated with emerged, plant overgrown areas.     

The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction

The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle–late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the Middle Triassic, Yunnan Province and southwest China shows this final stage of community assembly on the continental shelf. The fossil assemblage is a mixture of marine animals, including abundant lightly sclerotized arthropods, associated with fishes, marine reptiles, bivalves, gastropods, belemnoids, ammonoids, echinoderms, brachiopods, conodonts and foraminifers, as well as plants and rare arthropods from nearby land. In some ways, the Luoping biota rebuilt the framework of the pre-extinction latest Permian marine ecosystem, but it differed too in profound ways. New trophic levels were introduced, most notably among top predators in the form of the diverse marine reptiles that had no evident analogues in the Late Permian. The Luoping biota is one of the most diverse Triassic marine fossil Lagerstätten in the world, providing a new and early window on recovery and radiation of Triassic marine ecosystems some 10 Myr after the end-Permian mass extinction.     

陕西府谷前棱蜥类一新属及有关问题的讨论

本文详细记述了陕西府谷下三叠统和尚沟组中发现的一前棱蜥类骨架。依据头骨及头后骨骼特征订立一新属种:河套五角蜥(Pentaedrusaurus ordosianus gen.et.sp.nov.)。讨论中,对原归入前棱蜥科的袁氏三台龙(Santaisaurus yuani)的系统分类位置提出了修正意见,同时建议取消黄河保德蜥(Paoteodon huanghoensis)这一名称。     

Absence of Suction Feeding Ichthyosaurs and Its Implications for Triassic Mesopelagic Paleoecology

Mesozoic marine reptiles and modern marine mammals are often considered ecological analogs, but the extent of their similarity is largely unknown. Particularly important is the presence/absence of deep-diving suction feeders among Mesozoic marine reptiles because this would indicate the establishment of mesopelagic cephalopod and fish communities in the Mesozoic. A recent study suggested that diverse suction feeders, resembling the extant beaked whales, evolved among ichthyosaurs in the Triassic. However, this hypothesis has not been tested quantitatively. We examined four osteological features of jawed vertebrates that are closely linked to the mechanism of suction feeding, namely hyoid corpus ossification/calcification, hyobranchial apparatus robustness, mandibular bluntness, and mandibular pressure concentration index. Measurements were taken from 18 species of Triassic and Early Jurassic ichthyosaurs, including the presumed suction feeders. Statistical comparisons with extant sharks and marine mammals of known diets suggest that ichthyosaurian hyobranchial bones are significantly more slender than in suction-feeding sharks or cetaceans but similar to those of ram-feeding sharks. Most importantly, an ossified hyoid corpus to which hyoid retractor muscles attach is unknown in all but one ichthyosaur, whereas a strong integration of the ossified corpus and cornua of the hyobranchial apparatus has been identified in the literature as an important feature of suction feeders. Also, ichthyosaurian mandibles do not narrow rapidly to allow high suction pressure concentration within the oral cavity, unlike in beaked whales or sperm whales. In conclusion, it is most likely that Triassic and Early Jurassic ichthyosaurs were ‘ram-feeders’, without any beaked-whale-like suction feeder among them. When combined with the inferred inability for dim-light vision in relevant Triassic ichthyosaurs, the fossil record of ichthyosaurs does not suggest the establishment of modern-style mesopelagic animal communities in the Triassic. This new interpretation matches the fossil record of coleoids, which indicates the absence of soft-bodied deepwater species in the Triassic.     

三叠纪胎生主龙型海洋爬行动物

现代爬行动物的生殖方式包括卵生、卵胎生和“胎生”三种类型.总体而言,卵生即母体在陆地上产出羊膜卵,并依靠外界环境加以孵化;卵胎生系指羊膜卵在母体内孵化,随即产出幼子,其间胚胎的营养来源和代谢废物均限于羊膜卵内;所谓“胎生”,是指某些类群的卵在母体内孵化后没有立刻产出,胚胎与母体建立了某种程度的营养乃至气体交换关系,此后再以幼体的形式娩出.卵胎生和“胎生”见于有鳞类.在化石中,由于无法识别胚胎与母体的营养联系等信息,通常只以“生产方式”加以定义,即除卵生以外,所有“含胚胎的化石”都统称为“胎生”,目前“胎生”已有的准确记录包括鱼龙类、鳍龙类、沧龙类和离龙类.近期报道的“怀孕恐头龙”显示原龙类可能也有此种生殖方式,但标本的保存状态显示不能排除其“同类相食”之可能.本文记述了产自云南罗平地区中三叠系内一独立保存的、完整的圆胚状化石,标本的大小、形态、姿态和埋藏环境显示这是一个处于孵化后期、因某种原因而流产的胚胎.头后骨骼显示该标本代表了一种全新类型的海生原龙类,但是由于在个体发育中很多性状特征会有较大变化,因此胚胎乃至幼体标本不宜作为正型标本而建立新属种.这也是又一个主龙型爬行动物胎生的确切证据;同时这也进一步反映了盘县—罗平动物群中原龙类的高度多样性.     

What really happened in the late Triassic?

Major extinctions occurred both in the sea and on land during the Late Triassic in two major phases, in the middle to late Carnian and, 12–17 Myr later, at the Triassic‐Jurassic boundary. Many recent reports have discounted the role of the earlier event, suggesting that it is (1) an artefact of a subsequent gap in the record, (2) a complex turnover phenomenon, or (3) local to Europe. These three views are disputed, with evidence from both the marine and terrestrial realms. New data on terrestrial tetrapods suggests that the late Carnian event was more important than the end‐Triassic event. For tetrapods, the end‐Triassic extinction was a whimper that was followed by the radiation of five families of dinosaurs and mammal‐like reptiles, while the late Carnian event saw the disappearance of nine diverse families, and subsequent radiation of 13 families of turtles, crocodilomorphs, pterosaurs, dinosaurs, lepidosaurs and mammals. Also, for many groups of marine animals, the Carnian event marked a more significant turning point in diversification than did the end‐Triassic event.     

Triassic environments, climates and reptile evolution

A consideration of all the available data on Triassic vertebrate faunas, and their stratigraphic location reveals a relatively sudden extinction event among the last of the mammal-like reptiles and the herbivorous rhynchosaurs in the Norian of the Upper Triassic. This event was apparently quickly followed by the radiation of the dinosaurs, also in the Norian. This conclusion suggests that competition was not the main factor in the initial success of the dinosaurs, but opportunistic radiation following the extinction of major reptile groups. A global review of Triassic sedimentary facies shows that there were climatic and floral changes towards the end of the Triassic. It is envisaged that increasing aridity in the later Triassic, resulting from plate motions and particularly affecting Gondwanaland and southwestern Laurasia, brought about floral changes and then the reptile extinctions. With the rapid evolution of new floras of conifers and bennettitaleans, the dinosaurs came to dominate all terrestrial faunas within the space of only a few million years.