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1.
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   

2.
概述了鳄类动物的繁殖生物学特性。对在其它爬行动物中不多见,而在鳄类中普遍存在的亲体关怀行为和孵化温度决定后代性别的现象进行了阐述。并从生态学和进化论角度,对这些现象进行了讨论。  相似文献   

3.
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   

4.
本文简介了分支系统学意义上的鳄型动物(CrocodylomorphaWalker.1970)的组成。首次应用分支系统学方法讨论了重庆西蜀鳄的系统发有关系。本文的结论否定了西蜀鳄和西贝鳄类系统关系相近的论点,并认为前者比后者要原始得多,它是Mesoeucrocodylia中最原始的代表之一。  相似文献   

5.
根据对原标本的进一步修理,本文首先对宽头山东鳄(ShantungosuchusbrachycephalusYoung,1982)进行了重新记述,并对其特征作了修订。其主要特征为:头骨相对较宽;眼前孔小,上下分隔为二;轭骨前端不参与构成但接近眶前孔的后边缘;牙齿尖锐,第三枚上颌齿异常粗壮,比其它上颌齿至少大一倍;腭面诸骨表面光滑;基蝶骨腹面中央凹槽前窄后宽变化显著;侧欧氏管孔位于基蝶骨、基枕骨和外枕骨3者之间;下颌外孔大,齿骨后缘分为上、中、下三支;肩胛骨前外侧肩峰之上,发育一显著的嵴状突起。其次,把它与本属的其他两个种:莒县山东鳄(Shantungosuchuchuhsienensis)和杭锦山东鳄(Shantungosuchushangjinensis)做了比较。就目前的资料,还不能确立山东鳄属各种间的系统关系。  相似文献   

6.
汪仁平 《四川动物》1999,18(4):176-178
目前能进行国际贸易的鳄有12 种, 但它们只能被允许在某些国家和不同控制方式下的出口贸易。鳄类的人工饲养在世界上是一种新型产业, 它有二种饲养方式, 但都必须具备种群、食物、资金和技术四个基本要素。饲养技术的关键是对鳄生活习性的了解, 本文对几种鳄的栖息地和繁殖特点作了介绍。  相似文献   

7.
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   

8.
记山东山旺钝吻鳄(Alligator)一新种   总被引:1,自引:0,他引:1  
本文记述了钝吻鳄一新种 (Alligator luicus).这是鳄类化石在山东山旺中新统的首次发现,它为探讨钝吻鳄属的早期历史提供了新的资料.  相似文献   

9.
详细记述了采自四川自贡上株罗统上沙溪组的原鳄类-汇东四川鳄,在此基础上对该种的特征和了补充修订,四川鳄与山东鳄的关系最为密切,它们很可能代表原鳄类晚期演经的一个独立分支,骨骼特征表明四川鳄是一种适应于水中生活的肉食性动物。  相似文献   

10.
最后的土龙     
鳄类是过去爬行动物统治地球时代一直延续到现在的代表。与鸟类一样.鳄类是从初龙(槽齿龙等古爬行类)演化而来且唯一存活至今的爬行动物类群.它们和很早前就已灭绝的恐龙有亲缘关系。一二十年前.人们担心这些经历了小行星撞击地球灾难而存活下来的物种会因遭到人类的猎杀而步恐龙的后尘。然而在今天.曾经一度严重威胁鳄类生存的猎杀活动已很大程度上被合法、有序管理的人工饲养繁殖所取代,鳄类不再身陷灭绝的处境。  相似文献   

11.
似哺乳类爬行动物和哺乳类动物脑颅侧壁构造类型的演替   总被引:1,自引:1,他引:0  
本文对从原始似哺乳爬行动物进化到高级兽类哺乳动物过程中脑颅侧壁所发生的形态演化进行了分析,根据构造上的不同,将这些动物的脑颅侧壁的构造方式划分为四个构造类型,代表四个进化阶段。  相似文献   

12.
四川自贡大山铺蜀龙动物群——简报Ⅲ.蜥脚类   总被引:4,自引:2,他引:2  
本文记述了中侏罗世蜥脚类一新属种——巴山酋龙(Datousaurus bashanensts gen. et sp. nov.)对李氏蜀龙(Shunosaurus lii)的特征进行了补充,讨论了它们在蜥脚类进化过程中的位置。  相似文献   

13.
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   

14.
Synopsis Latimeria is the product of a long coelacanth lineage, usually viewed as having changed very little. In this paper a classification of better known coelacanth genera is proposed based on a cladistic computer analysis of 56 morphological characters. Biometrical data are then matched with the classification to explore the possibility of identifying subtle change. It is concluded that throughout coelacanth history there have been changes in the structure of the vertebral column involving an overall increase in the number of vertebral elements, and a consequent crowding of these elements within the abdominal region. These changes may be associated with increasing lobation of the second dorsal and anal fins. In the skull, parameters involving the intracranial joint have also changed in such a way that the anterior part of the skull has lengthened in relation to the posterior part and this may be associated with an increase in length of the basicranial muscle.Abbreviations in text figures Ang angular - a.o.r anterior opening of th rostral organ - Art articular - ba.cr.m basicranial muscle - Basi basisphenoid - Boc basioccipital - bpt.pr basipterygoid process - c.p.l cheek pit line - De dentary - Esc extrascapular - eth.sp etmosphenoid - f.e frontoethmoid - Fr frontal - Fr.d descending process of frontal - intr. j intracranial joint - io.s interorbital septum - sc jugal sensory canal - L.e lateral ethmoid - m.Cor modified coronoid - Mm memtomeckelian - m.ot.sc medial branch of otic canal - Op operculum - o.p.l oral pit line - ot,occ otico-occipital - Pa parietal - Pa.d descending process of parietal - Par parasphenoid - pa.s parietal shield - p.Cor principal coronoid - Po postorbital - Pop preoperculum - p.o.r posterior openings of the rostral organ - Pmx premaxilla, Pre-preorbital - Pro prootic - Pro.p posterior process of prootic - Rart retroarticular - Sc.o sclerotic ossicle - So supraorbital - Soc supraoccipital - Sop suboperculum - Sp spiracular - spl splenial - Sq squamosal - Stt supratemporal - Stt.com supratemporal commissure - Stt.d descending process of supratemporal - Par.a.w ascending wing of parasphenoid - Te tectal - X level of vagus exit  相似文献   

15.
The purpose of this article is to gain insight into the ossification sequence of the palatoquadrate and the adjacent lateral cranial wall of prehatching Alligator mississippiensis, a process about which there is almost no published information. Results were obtained by studying serial histological sections of the series of ontogenetic stages and enlarged wax-plate models of several stages. The cartilage of the palatoquadrate starts to ossify endochondrally in the quadrate portion of the pars pterygoquadrata palatoquadrati in Stage 6A. In this stage, a bone, called the lamina palatoquadrati anterior here, appears at and close to the anteromedial wall of the cartilaginous pterygoid portion of the pars pterygoquadrata. The lamina palatoquadrati anterior ossifies in membrane. Later in ontogeny, the lamina palatoquadrati anterior spreads into the cavum epiptericum and sheathes the posterior portion of the trigeminal ganglion laterally. The jaw adductor muscles insert at the outer surface of the lamina palatoquadrati anterior. The lamina palatoquadrati anterior is a new structure not previously recorded in crocodylians or any other Recent reptile. The topology, mode of ossification, and functional anatomy of the lamina palatoquadrati anterior correspond to those of the membranous ossification of the alisphenoid of marsupials. Another bone, called the lamina prootici anterior here, spreads in membrane from the anterolateral wall of the prootic portion of the otic capsule into the prootic fenestra, above the trigeminal ganglion. The lamina prootici anterior represents a structure not recorded previously in crocodylians. It contributes to the orbitotemporal braincase wall.  相似文献   

16.
根据一保存完整的骨骼(包括头骨、下颌和全部头后骨骼)建立了鳍龙类的一新属新种——利齿滇东龙(Diandongosaurus acutidentatus gen.et sp.nov.)。标本采自云南省罗平县中三叠世安尼期关岭组上段。新属种既具有肿肋龙类(包括Dactylosaurus,Anarosaurus,Serpianosaurus和Neusticosaurus)吻部两侧不收缩、眶前区域长于眶后区域、眼眶大于上颞孔等典型特征,同时又具有幻龙类(包括Simosaurus和nothosaurians)前颌和下颌前部犬齿型齿发育、上颌具1或2个犬齿型齿等典型特征。新种的额骨和顶骨均愈合,额骨两后外侧支的末端后延超过上颞孔前缘,轭骨和鳞骨相交将眶后骨排除于下颞孔之外,方轭骨发育,锁骨前外侧缘具一突起,3对荐肋以及最前部尾肋的外侧端均未见明显收缩。这些特征也多表现出肿肋龙类和幻龙类的混合特征。此外,新种还具有一些较为独特的特征,包括前额骨和后额骨沿眼眶背缘相交,第3至第8对尾肋的长度超过荐肋,后肢末端发育异常膨大的爪趾骨。系统关系分析表明,滇东龙既不是肿肋龙类也不是幻龙类;它可能与由乌蒙龙、幻龙类和传统的肿肋龙类所构成的分支亲缘关系最近,为始鳍龙类基干类群。  相似文献   

17.
本文介绍了以短吻云南兽为代表的一种耳区结构.它表明在三列齿类爬行动物里已经出现有发育的耳蜗壳以及在其内侧通过的颈内动脉等进步性质,听腔亦趋封闭.云南兽的中耳腔外侧出现了一条曲折的骨质外耳道,侧枕骨突外侧明显的沟可能表明方骨后耳膜之存在.  相似文献   

18.
The Middle Jurassic (Late Bathonian) Mammal Bed at Kirtlington, Oxfordshire, has yielded a rich assemblage of small vertebrates including mammals, frogs, salamanders and small reptiles. This paper describes the skull of a new diapsid reptile, Marmorelta oxoniensis, which was common within the fauna. The skull is gracile with large orbits and relatively long external nares. The frontals and parietals are single in the adult and almost separated on the roof of the skull by the postfrontals. The temporal region shows a mosaic of primitive and derived character states. The quadrate was firmly held to the skull by a large squamosal and a small, free, quadratojugal was retained. However, reduction of the anterior process of the quadratojugal and of the posterior process of the jugal left the lower temporal fenestra broadly open. Comparison with other diapsids leads to the conclusion that Marmoretta was a lepidosauromorph, most probably the sister taxon of Lepidosauria.  相似文献   

19.
记述了在四川自贡大山铺发现的孙氏鳄一新种———蜀南孙氏鳄 (Sunosuchusshunanensissp .nov .)。新种窄长的吻部 ,小的颅顶平台 ,额骨沿中线具一纵嵴 ,一对裂隙状的前腭孔位于眶下孔之前方 ,方骨腹面的嵴B特别发育等 ,与孙氏鳄的其他种很相似 ,但新种的吻部特别窄长 ,为吻后部长度的 3倍 ,上颌凹特别发育 ,颅顶平台短而宽 ,颞间部宽度大于眶间部宽度 ,泪骨在眼眶前缘处隆起成嵴 ,下颞孔小 ,呈裂隙状 ,鳞骨侧缘不增厚 ,也无附着上耳盖的沟嵴状构造 ,基枕骨侧缘和外枕骨内腹缘具一明显的隆嵴等 ,与孙氏鳄的其他种有明显区别  相似文献   

20.
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