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1.
本文详细记述了陕西府谷下三叠统上部二马营组底部的一古鳄类化石.据其骨骼形态特征拟订为古鳄亚目(Proterosuchia)、引鳄科(Erythrosuchidae)的一新属种:石拐古城鳄(Guchengosuchus shiguaiensis gen. et sp. nov.),同引鳄科内已知属的对比,表明新属古城鳄与武氏鳄 Vjushkovia 的关系最为接近.  相似文献   

2.
记裂头鳄属(Dibothrosuchus)一新种   总被引:4,自引:4,他引:0  
本文记述的裂头鳄属-新种 (Dibothrosuchus xingsuensis sp. nov.)的标本采自云南禄丰盆地下禄丰组深红层.通过描述,对裂头鳄属属级特征作了补充.新种的头骨中鳞骨缺失降突;方骨极度向前背方伸展,形成大的耳凹,乌喙骨具后腹突,以及具有鳄类式的腕骨等,表明裂头鳄属应改属为楔形鳄科 (Sphenosuchidae).根据该科各属的头骨中方骨与脑颅侧壁的连接关系,可以清楚地看到楔形鳄科在这局部解剖学上存在一连续的发展过程.在形态上,裂头鳄属和南非的 Sphenosuehus (典型属)最为相近.  相似文献   

3.
记湖南衡东盆地的平顶鳄一新种   总被引:1,自引:1,他引:0  
本文记述了产自湖南衡东的一鳄类头骨化石——衡东平顶鳄Planocrania hengdongensissp.nov.并对这一属的分类位置进行了讨论,依据次生腭的性质将它归入真鳄亚目鳄科。  相似文献   

4.
重新研究了济源四足动物群的材料,表明其以锯齿龙类的复齿河南龙为主体,还包括至少三种迟滞鳄类和一种犬齿兽,可能还有一种凶脸兽。根据甲片特征推测,迟滞鳄类至少包括中国毕氏螈Bystrowiana sinica,扁平济源盖螈(新属新种)Jiyuanitectum fl atum gen.et sp.nov.以及大型脊廊盖螈(新种)Dromotectum largum sp.nov.。根据四足动物组合,济源动物群大致可以与俄罗斯Sokolki组合带的Ilinskoe亚带以及南非的小头兽组合带对比。  相似文献   

5.
安徽古新世(犭亚)兽科的新属种(下)   总被引:1,自引:1,他引:0  
皖兽 Wanogale gen.nov. (图版Ⅱ,5;插图9)属的特征同属型种 W.hodungensis sp.nov. 河东皖兽 Wanogale hodun-gensis sp.nov.正型标本右下颌骨一段,带有M_2及M_1的跟座。编号:V4273。野外编号:71001。  相似文献   

6.
山西垣曲河堤组寨里段的低等四足类动物群   总被引:4,自引:3,他引:1  
本文记述了我国晚始新世的一低等四足类动物群,包括三种蜥蜴和两种鳄类.其中的宽额半鳄蜥(Hemishinisaurus latifrons gen. et sp. nov.)是我国首次发现的异蜥科化石;垣曲响蜥(Tinosaurus yuanquensis sp. nov.)是响蜥属在我国的最晚代表.  相似文献   

7.
记述佯鳄蚱属8种,其中包括2新种:峨眉佯鳄蚱Paragavialidium emeiensis sp.nov.及齿股佯鳄蚱Paragavialidium serrifemura sp.nov.。附有分种检索表、分布及文献引证。新种的模式标本保存于陕西师范大学动物研究所。  相似文献   

8.
吴肖春  刘俊  李锦玲 《古脊椎动物学报》2001,39(4):251-265,T001
初步研究了山西省永和县桑壁镇铜川组二段产出的两件初龙形类化石标本 (IVPPV1 2 3 78,V 1 2 3 79) ,在此基础上建立了一新属新种———桑壁永和鳄 (Yonghesuchussangbiensisgen .etsp .nov .)。它以下列共存的衍生特征区别于其他初龙形类 (archosauriforms) :1 )吻部前端尖削 ;2 )眶前窝前部具一凹陷 ;3 )眶前窝与外鼻孔间宽 ;4)眶后骨下降突的后 2 / 3宽且深凹 ;5 )基蝶骨腹面有两个凹陷 ;6 )齿骨后背突相当长 ;7)关节骨的反关节区有明显的背脊 ,有穿孔的翼状的内侧突 ,以及指向前内侧向和背向的十分显著的后内侧突。由于缺乏跗骨的形态信息 ,目前很难通过支序分析建立永和鳄的系统发育关系。但可以通过头骨形态来推测永和鳄在初龙形类中的系统位置。永和鳄有翼骨齿 ,这表明它不属于狭义的初龙类 (archosaurians)。其通过内颈动脉脑支的孔位于基蝶骨的前侧面而不是腹面 ,在这点上永和鳄比原鳄龙科 (Proterochampsidae)更进步 ,这表明与后者相比永和鳄和狭义的初龙类的关系可能更近。在中国早期的初龙形类中 ,达坂吐鲁番鳄 (Turfanosuchusdabanensis)与桑壁永和鳄最接近 ,但前者由于内颈动脉脑支的孔腹位而比后者更为原始。根据以上头骨特征以及枢后椎椎体之间间椎体的存在与否 ,推测派克鳄 (Euparkeri  相似文献   

9.
记述了四川省自贡市汇东新区自贡市乳品厂发现的西蜀鳄一新种——周氏西蜀鳄(Hsisosuchus chowi sp.nov.)。新种区别于西蜀鳄已知种的特征是:鼻骨后部沿缝合线有一浅的纵凹,额骨的眶缘向上凸起成嵴,沿额骨缝合线也隆起成一微弱的纵嵴,上颞窝的内侧缘向上凸起呈明显的嵴,顶骨具一前中突,侧视颧骨腹缘呈明显的波曲状,眶后骨前侧角约90°,鳞骨后侧突特别拉长,向侧下后方伸展,使鳞骨侧缘明显向内侧弓曲,左右外枕骨的枕髁部分不相接,翼骨的腹中嵴源于翼骨主体部分,内鼻孔位置比较靠前。此外,齿骨外面和夹板骨腹面具有发达的沟和嵴状雕饰,夹板骨参与下颌联合的部分比较长,肩胛片异常扩展,乌喙骨远端宽于近端,肱骨头增厚并强烈向内侧扩展,三角肌嵴发达,桡侧腕骨具发达的尺骨突,尺侧腕骨远端宽于近端,6列荐前部腹部骨板和3列尾部腹部骨板,也可能是周氏西蜀鳄的衍生特征,但这些性状在大山铺西蜀鳄中情况不明,有待更多的材料来证实。杨钟健、周明镇(1953)在建立西蜀鳄属之初就已注意到西蜀鳄是一种特化的鳄类,认为西蜀鳄不仅将原始特征和进步特征混存于一身,而且还具有一些一般鳄类所没有的独特性质。以此为基础,他们建立了西蜀鳄科。目前西蜀鳄类动物发现并不多,仅有1属2种,即重庆西蜀鳄和大山铺西蜀鳄,而且材料不完整,特别是头后骨骼保存不理想。周氏西蜀鳄的发现不仅扩大了西蜀鳄类的分布范围,而且还增加了我们对这一特化鳄类的认识。  相似文献   

10.
记述了2012年在山西柳林三交二马营组上部采集的一个兽头类下颌标本,将其命名为幻阔齿兽三交种(Nothogomphodon sanjiaoensis sp.nov.)。新种以下列特征区别于属型种N.danilovi:齿骨下缘起伏,犬齿基部卵圆形,犬齿与第一犬后齿间有显著间隙,犬后齿后缘无辅助齿尖。幻阔齿兽以其特殊的犬后齿形态与具裂齿的基干犬齿兽相似,它也是已知的唯一一类具有这种复杂裂齿齿系的兽头类。将俄罗斯的引鳄动物群与中国的肯氏兽-山西鳄组合带进行比较发现,幻阔齿兽是二者唯一共有的属,而中国的二马营组与克拉玛依组却没有共享的属。  相似文献   

11.
Abstract: Fossils of dyrosaurid crocodyliforms are limited in South America, with only three previously diagnosed taxa including the short‐snouted Cerrejonisuchus improcerus from the Paleocene Cerrejón Formation of north‐eastern Colombia. Here we describe a second dyrosaurid from the Cerrejón Formation, Acherontisuchus guajiraensis gen. et sp. nov., based on three partial mandibles, maxillary fragments, teeth, and referred postcrania. The mandible has a reduced seventh alveolus and laterally depressed retroarticular process, both diagnostic characteristics of Dyrosauridae. Acherontisuchus guajiraensis is distinct among known dyrosaurids in having a unique combination of craniomandibular characteristics, and postcranial morphology that suggests it may have occupied a more placid, fluvial habitat than most known Old‐World dyrosaurids. Results from a cladistic analysis of Dyrosauridae, using 82 primarily cranial and mandibular characters, support an unresolved relationship between A. guajiraensis and a combination of New‐ and Old‐World dyrosaurids including Hyposaurus rogersii, Congosaurus bequaerti, Atlantosuchus coupatezi, Guarinisuchus munizi, Rhabdognathus keiniensis and Rhabdognathus aslerensis. Our results are consistent with an African origin for Dyrosauridae with multiple dispersals into the New World during the Late Cretaceous and a transition from marine habitats in ancestral taxa to more fluvial habitats in more derived taxa.  相似文献   

12.
Abstract:  Additional material of a large specimen of tristichopterid fish from the Upper Famennian Evieux Formation of Belgium is described. This large fish was previously assigned to Tristichopteridae gen. et sp. indet. due to the lack of diagnostic anatomical data. New available material consists of the internal surface of the parietal shield, vomers and anterior part of the parasphenoid, subopercular and submandibulo-branchiostegal bones, and an internal view of the anterior part of the mandible. A possible autapomorphy of the new form from Belgium, Langlieria socqueti gen. nov. et sp. nov., is the absence of marginal teeth on the vomer except on its most lateral part. Apart from these features, it only differs from the genus Mandageria from Australia in the absence of marginal teeth between the dentary fang and the mandibular symphysis, in the presence of a raised marginal crest lateral to the anterior coronoid fang, and in the presence of numerous small marginal teeth on the premaxilla. It differs from the cosmopolitan genus Eusthenodon in a number of respects: the supratemporal, tabular, and postparietal bones are superficially fused, as are the intertemporal and parietal bones, the dermal ornament is proportionally very fine, and the denticulated field of the parasphenoid stands proud rather than being recessed into the body of the bone.  相似文献   

13.
The development of the jaw joint between the palatoquadrate and proximal part Meckel's cartilage (articular) has recently been shown to involve the gene Bapx1. Bapx1 is expressed in the developing mandibular arch in two distinct caudal, proximal patches, one on either side of the head. These domains coincide later with the position of the developing jaw joint. The mechanisms that result in the restricted expression of Bapx1 in the mandibular arch were investigated, and two signaling factors that act as repressors were identified. Fibroblast growth factors (Fgfs) expressed in the oral epithelium restrict expression of Bapx1 to the caudal half of the mandibular arch, while bone morphogenetic proteins (Bmps) expressed in the distal mandibular arch restrict expression of Bapx1 to the proximal part of the mandible. Application of Fgf8 and Bmp4 beads to the proximal mesenchyme led to loss of Bapx1 expression and later fusion of the quadrate and articular as the jaw joint failed to form. In addition to fusion of the jaw joint, loss of Bapx1 lead to loss of the retroarticular process (RAP), phenocopying the defects seen after Bapx1 function was reduced in the zebrafish. By manipulating these signals, we were able to alter the expression domain of Bapx1, resulting in a new position of the jaw joint.  相似文献   

14.
第四纪响蜥(Tinosaurus)化石的首次发现   总被引:2,自引:0,他引:2  
在陕西洛南张坪洞穴的第四系中采得一些响蜥类(Tinosaurus)化石,有保存相当完好的上下齿骨和齿列,这是响蜥在第四纪的首次报道,使该属化石的地史分布从早第三纪延伸到第四纪。新材料下颌骨较粗壮,但个体很小,有齿间沟,同时兼具亚洲种及北美种的某些特征,因此建立一新种Tinosaurus luonanensis sp.nov.。  相似文献   

15.
Abstract:  This paper describes a new genus and species of dyrosaurid, Chenanisuchus lateroculi gen. et sp. nov. (Crocodyliformes, Mesoeucrocodylia) from the Thanetien (Late Palaeocene) of the Oulad Abdoun Basin, Morocco. This new taxon has a particularly short snout, as well as widely separated and laterally facing orbits. In the holotype, the mandible exhibits a retroarticular process that is strongly depressed posterior to the glenoid fossa, bringing the ventral margin of the medial wing of the articular to the same level as the ventral margin of the retroarticular process. This feature is shared with Congosaurus bequaerti , Dyrosaurus and isolated dyrosaurid material from Mali and Niger, but is absent in the putative closely related crocodyliforms, such as pholidosaurids and Terminonaris , and could be a dyrosaurid character.  相似文献   

16.
In southern African samples of early hominid remains, maxillary and mandibular teeth (deciduous-plus-permanent) have a virtually equal chance of accumulating in the dolomitic limestone cave deposits, of being preserved therein and recovered therefrom. Thus, of 1066 fossil teeth ofAustralopithecus spp. plusHomo habilis, 51.9 per cent are maxillary and 48.1 per cent mandibular. On the other hand, the East African sample of 847 early hominid, deciduous-plus-permanent teeth, departs more strikingly from a 1∶1 ratio: it comprises 41.0 per cent maxillary and 59.0 per cent mandibular teeth. It is inferred that mandibular teeth have a somewhat better chance of accumulating and being preserved in, and being recovered from, the open, fluvial, lacustrine and deltaic sedimentary environments of the East African sites. The dental proportions are approximately matched by the proportions of jaws. For example, the maxilla: mandible proportions at Koobi fora in northern Kenya are 33.0∶67.0 for teeth and 21.6∶78.4 for jaws. In other words, the preponderance in favour of mandibular remains is somewhat more marked in the case of jaws than of teeth, this distinction doubtless reflecting the more fragile bony structure of the maxilla and the sturdier construction of the mandible. This first study known to the author of the differential distribution of maxillary and mandibular teeth of the Plio-Pleistocene hominids leads the author to hypothesize that, where environmental conditions at the place and time of the death of the hominids have been non-destructive, non-dispersive, relatively mild and protective, maxillae and mandibles may be expected to have been conserved and recovered in approximately equal proportions—and likewise of maxillary and mandibular teeth. On the other hand, the more brutal and destructive the sedimentary environment and other taphonomic influences have been, at the place and time when the hominid individuals died, the more likely it is that the maxillary and mandibular remains of jaws and teeth will deviate from equality of proportions, generally at the expense of the maxillae and upper teeth. Hence, it is proposed that the upper jaw/low jaw ratio (Mx/Mn jaw ratio) and the maxillary teeth/mandibular teeth ratio (Mx/Mn dental ratio) may serve as two useful new gauges of the rigour of palaeo-ecological and taphonomic conditions.  相似文献   

17.
记述了浙江长兴县煤山剖面、江西修水县四都乡东岭剖面和信丰县铁石口镇铁石口剖面二叠/三叠系界线以下的软骨鱼类10个类别的微体化石,包含5科6属5种,其中有3新属5新种,它们是:刘氏煤山鲨(Meishanselache liuigen.et sp.nov.)、王氏长兴鲨(Changxingsela-che wangigen.et sp.nov.)、东岭中华尖齿鲨(Sinacrodus donglingensis gen.et sp.nov.)、修水滑齿鲨(Lissodus xiushuiensis sp.nov.)和江西多尖齿鲨(Polyacrodus jiangxiensis sp.nov.)。浙、赣两省的这批软骨鱼类微体化石显示两个特点:组成以弓鲛超科化石为主;发现于特提斯区三叠纪的鲨类与发现于中国南方晚二叠世的鲨类具有密切的亲缘关系。这是包含全球二叠/三叠系界线层型剖面和点位(GSSP)在内的全球二叠/三叠系界线以下软骨鱼类微体化石序列的首次报道。软骨鱼类是我国鱼类化石研究中最为薄弱的一个环节,本文化石的记述大大地填补了这个薄弱环节。  相似文献   

18.
华南古新世哺乳类一新科   总被引:1,自引:1,他引:0  
本文记述了一个新科(丽(犭亚)科)的两个新属和四个新种。文中除对四新种进行了较详细的描述与对比外,还初步讨论了丽(犭亚)科、(犭亚)科与假古猬科同Kennalestes和zalambdalestids之间的亲缘关系。从目前材料来看,在形态上,丽(犭亚)比Gypsonictops更接近于Kennalestes。丽(犭亚)科有可能是后者的古新世后裔,(犭亚)科和假古猬科的起源或许与达种白垩纪真兽类也有密切关系。  相似文献   

19.
河南淅川始新世核桃园组獏化石   总被引:3,自引:1,他引:2  
这里记述了河南淅川核桃园组中五种獏化石:Breviodon minutus,Schlosseria hetaoyuanensissp.nov.,Deperetella sichuanensis,Teleolophus danjiangensis sp.nov.,Pachylophus xui gen.etsp.nov.,并认为其时代大体相当于伊尔丁曼哈阶。文中也对脊齿獏亚科的分化和Teleolophus与Deperetella两属系统关系作了一些探讨。  相似文献   

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