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1.
记陕北子长晚三叠世一新的古鳕类   总被引:5,自引:0,他引:5  
记述了陕北子长晚三叠世古鳕科(Palaeoniscidae)一新属新种──子长瓦窑堡鳕(Wayaobulepis zichangensis gen. et sp. nov.)。其一般形态特征如身体长纺锤形、背鳍基长,后部对着腹鳍和臀鳍之间的空隙、鳍条粗壮、饰缘棘鳞细小、悬挂骨倾斜、鳃盖骨很高大、鳞片小及横列鳞数目多等,与澳大利亚中至晚三叠世的Myriolopis很相似,但新属具有吻较尖、背鳍鳍条数目较少、鳞片具有众多的斜嵴、后缘成梳齿状以及具有背嵴鳞等显著特征区别于Myriolopis。瓦窑堡鳕在体形、鳍的位置、鳃盖骨高大及鳞片的纹饰等方面也与欧洲中至晚三叠世的 Gyrolepis相似,但新属以背鳍基较长、臀鳍基较短、背峪鳞发达及鳍条粗壮等特征区别于Gyrolepis。根据瓦窑堡鳕的性质和化石层位的情况,将合鱼化石地层的时代定为晚三叠世。  相似文献   

2.
记述了辽宁西部九佛堂组和义县组中华弓鳍鱼一新种:辽宁中华弓鳍鱼Sinamia liaoningensis,并与该属的其他种进行了比较.新材料具有中华弓鳍鱼科的3个定义特征:单一的顶骨,三对额外肩胛骨和膜质翼耳骨短并与顶骨等长,无疑应归入该科.新种的后眶下骨较小,背鳍长大,鳞片菱形,因此,归入中华弓鳍鱼属.辽宁中华弓鳍鱼在以下几个方面不同于中华弓鳍鱼的5个已知种:体型短粗,吻骨较短,鼻骨近四方形,围眶骨较多(6),前鳃盖骨强烈弯曲,背鳍条较少(18),尾鳍条较多(16),臀鳍鳍基起点到鱼体背缘的鳞列较多(32),鳞片后缘不具锯齿,尾鳍具有纤维状的角质鳍条.  相似文献   

3.
记述了在江苏句容发现的中华鳞齿鱼属(Sinolepidotus)一新种——长背鳍中华鳞齿鱼(Sinolepidotus longidorsalis sp.nov)。新种的一般形态特征如身体高纺锤形,背鳍长,臀鳍离尾鳍近,头骨外部骨片的形状及排列格局,口裂小,下颌骨有较高的冠状突,口缘牙齿高而尖,体侧中部和背区的一些鳞片高显著大于宽等,与浙江早白垩世的浙江中华鳞齿鱼(Sinolepidotus chekiangensis)很相似。但新种具有背鳍较长,背鳍鳍条数目较多,吻突尖,及鳞片后缘梳状齿不发育等特征区别于浙江中华鳞齿鱼。此外,评论了中华鳞齿鱼属的系统位置,认为它的形态特征与Paralepidotus很相似,对它原列入半椎鱼科提出疑问。根据长背鳍中华鳞齿鱼的性质并参考有关地质古生物资料,将含鱼层杨冲组的时代定为早白垩世。  相似文献   

4.
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   

5.
记述了云南曲靖潇湘区关底组(志留系罗德洛统)真盔甲鱼类一新属、新种——长孔盾鱼(Dunyu longiforus gen.et sp.nov.),丰富了以梦幻鬼鱼为代表的潇湘脊椎动物群的组成.该新属具真盔甲鱼科的鉴别特征:后眶上管和中背管二者连续过渡,后端两侧辏合呈“U”字形,侧背管仅发出3条侧横管.新属内角缺如,这一特征过去在真盔甲鱼科中仅见于真盔甲鱼属.新属区别于真盔甲鱼属的主要特征有:角向后方延伸,呈棘状或叶状;头甲最宽处位于角末端之前,宽长比小于1.1;中背孔末端超越眶孔后缘连线.基于对秀山真盔甲鱼头甲标本的重新观察,将秀山真盔甲鱼归入盾鱼属.新种区别于秀山盾鱼(Dunyu xiushanensis)的特征有:个体较大,头甲长大于宽;角呈棘状;眶孔位置相对靠前,头甲眶前区与眶后区的长度之比小于0.75;多边形崮状瘤点,较大,长可超过2 mm.  相似文献   

6.
记述了云南曲靖潇湘区关底组(志留系罗德洛统)真盔甲鱼类一新属、新种——长孔盾鱼(Dunyu longiforus gen.et sp.nov.),丰富了以梦幻鬼鱼为代表的潇湘脊椎动物群的组成。该新属具真盔甲鱼科的鉴别特征:后眶上管和中背管二者连续过渡,后端两侧辏合呈"U"字形,侧背管仅发出3条侧横管。新属内角缺如,这一特征过去在真盔甲鱼科中仅见于真盔甲鱼属。新属区别于真盔甲鱼属的主要特征有:角向后方延伸,呈棘状或叶状;头甲最宽处位于角末端之前,宽长比小于1.1;中背孔末端超越眶孔后缘连线。基于对秀山真盔甲鱼头甲标本的重新观察,将秀山真盔甲鱼归入盾鱼属。新种区别于秀山盾鱼(Dunyu xiushanensis)的特征有:个体较大,头甲长大于宽;角呈棘状;眶孔位置相对靠前,头甲眶前区与眶后区的长度之比小于0.75;多边形崮状瘤点,较大,长可超过2mm。  相似文献   

7.
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   

8.
金线鲃属鱼类一新种(鲤形目:鲤科)   总被引:1,自引:0,他引:1  
作者于1986年6月在贵州盘县一溶洞的水体中采到金线鲃属鱼类一新种,命名为角金线鲃,新种Sinocyclocheilus angularis sp. nov.。本新种形状怪异,头背缘末端具一朝前的角状突,其内有顶骨突;眼正常;侧线鳞明显;鳔后室发达等特征而易与金线鲃属其他种相区别。  相似文献   

9.
谭锴  王曦  卢立伍 《古生物学报》2015,54(2):174-183
本文记述的标本采自宁夏中卫晚石炭世土坡组下部,属于个体较小的扁体鱼类,身长与身高近相等,约3cm。眼眶大,眶下感觉管明显。鳃盖骨大致呈长条形,下鳃盖骨大小与鳃盖骨相近,前鳃盖骨呈椭圆状,匙骨强壮。锁骨保存于匙骨前上部。背、腹棘鳞发育。胸鳍小,腹鳍没有保存。背鳍中等长,臀鳍与背鳍等长,均起点位于身体最高点后。尾鳍呈外形对称的歪型尾。全身覆盖长条形鳞,胸鳍下方具有一枚异常大型的鳞片。经过与北美、澳洲以及中国浙江的扁体鱼类标本对比,发现其间有明显差异,应为一新属新种——小型宁夏扁体鱼(Ningxiaplatysomus parvus gen.et sp.nov.),归于扁体鱼亚目,科不定。  相似文献   

10.
根据可能发现于江西赣州晚白垩世南雄组地层中一件标本报道了窃蛋龙科一新属种——斑嵴龙。新标本具有以下不同于其他窃蛋龙属种的特征:由前颌骨和鼻骨形成的脊冠具有阶梯状的后端,表面有两个纵向的沟槽和许多倾斜的条痕;外鼻孔延长,其后侧与眶骨相近;翼骨腭骨支背缘有一深窝;齿骨后背缘有纵向沟槽;上隅骨前背缘有小结节。斑嵴龙腭部和下颌的一些特征不同于窃蛋龙科的其他属种,但近似于更原始的窃蛋龙类。这些特征表明斑嵴龙代表窃蛋龙科中相对原始的一个属种。这一系统发育假说得到了定量的系统发育分析的支持。斑嵴龙的发现不仅增加了晚白垩世窃蛋龙科的分异度,而且为这一类群的特征演化提供了重要信息。  相似文献   

11.
A NEW GENUS OF HIODONTIDAE FROM LUOZIGOU BASIN, EAST JILIN   总被引:1,自引:1,他引:0  
<正> Manchurichthys (Saito, 1936) has been, for a long time, the only representative of fossil vertebrate known from the Oil-bearing member of Dalazi Formation, Luozigou Basin, East Jilin. Since 1978, some new materials have been collected there by the Regional Geological Brigade of Jilin Province and the present author. Two more forms of fossil fishes are not known to occur in the rocks of this section. One is Sinarnia luozigouensis (Li, 1984) which is referred to Amiiformes; the other, Yanbiania (gen. nov.), is described in this paper and included in the osteoglossomorphan family Hiodontidae.  相似文献   

12.
Five closely related species of fossil cichlids collected from an Eocene site in Tanzania, East Africa, represent the oldest known cichlids. The specimens are whole-body, articulated fishes that are extremely well preserved and, therefore, have the potential to add to our knowledge of the history of this family. Modern cichlids are particularly well known for the numerous species flocks of the East African Great Lakes. A great deal of research is ongoing regarding all aspects of the fishes in these flocks, including their evolutionary history The new collection of fossils reported here is interpreted as representing a species flock that arose in a small crater lake. These fossils indicate that cichlids' ability to form species flocks evolved early in the history of this family.  相似文献   

13.
A new fossil fish family (Acregoliathidac) with only one known species ( Acregoliathidac rancii gen. et sp.n.) is described. The material consists of large Scales coming from the Plio-Pleistocene of Acre State, Northern Brazil. Studies involving X-ray radiograph, SEM and optical microscopic methods demonstrated the peculiarity of the new materia1. whose affinities with the classical fish scale models are hardly evident. The scales of A. rancii are round, with large exposed and emberddted areas. They bear concentric circuli and the posterior fields is covered with many layers of a glassy and birefringent tissue. Two bony layers are clearly distinguishable: the basal isopedin and, above, an important cell-containing spongiosa (protohaversian bone tissue). The affinities of the fossil with both sarcopterygian and actinoplerygian fishes are discussed and the Acregoliathidac are considered to be teleostean fishes of uncertain systematic relationships with other families or oders of this subdivision.  相似文献   

14.
滇西晚石炭世一早二叠世苔藓虫   总被引:2,自引:0,他引:2  
简述了4个双壳类化石组合特征及沉积环境,描述了双壳类2新属(Sichuatrigonia, Pseudoburmesia)和11新种(包括新亚种).  相似文献   

15.
The present-day faunas of the great African lakes present some of the world's best examples of 'explosive speciation'. Lakes Victoria and Malawi each probably have several hundred endemic species of cichlid fishes. Much can be inferred about the evolution of these fishes from morphology, behaviour and intra-lacustrine distribution and from the fact that they include taxa ranging from local races, through sibling species, to forms that display extensive differentiation. The time taken to acquire specific distinctness can sometimes be accurately defined, but fossil lineages are unknown. A recent study of a fossil sequence of molluscs in the Turkana basin throws new light on the history of African lake faunas. It also claims to have resolved events during speciation. While critical analysis based on our knowledge of living molluscs in this area fails to substantiate this claim, the fossil molluscs complement information provided by the biology of extant fishes and invertebrates and emphasize the importance of these lakes in the study of evolution in living and extinct populations.  相似文献   

16.
Abstract: The phosphate deposits of the Tilemsi Valley, Republic of Mali, West Africa, are well known for their rich fossil vertebrate fauna including fishes, crocodilians, snakes and mammals. Despite this, the exact age of the deposits has been in some doubt. Here, a new species of catfish, Nigerium tamaguelense sp. nov., is described from the phosphate deposits at Tamaguélelt, Tilemsi Valley, based on a large collection of 29 well‐preserved crania. The crania are compared with the known species of Nigerium, N. wurnoense White and N. gadense White. The genus Nigerium is reviewed and now placed in the family Claroteidae based on a combination of three derived characters. Nigerium is compared with other African fossil catfish genera and the fossil record of catfish families in Africa is reviewed. The new evidence presented here shows the Claroteidae to be the earliest occurring catfish family in Africa. Evidence is also presented for an Early Eocene age for the phosphate deposits at Tamaguélelt.  相似文献   

17.
Abstract:  A recent collection of actinopterygian fossil fishes from a previously unreported locality in the Cenomanian or Turonian of southeastern Morocco includes a single specimen of a macrosemiid fish. Macrosemiids are more common in Jurassic and Early Cretaceous deposits, with the previously known range of the family being Late Triassic through Aptian or Albian. This discovery therefore extends the temporal range of the family into the Late Cretaceous. Moreover, macrosemiids had not previously been reported from northern Africa or the Moroccan area of the Tethys basin; therefore, this fossil also increases the geographical range of the family. The Moroccan macrosemiid is described in a new genus and species, Agoultichthys chattertoni . A phylogenetic analysis places it basal to all other genera of the family with the exception of Notagogus . Diagnostic characters of the new species include the high number of scales laterally along the body and the greater number of dorsal fin rays than in other members of the family.  相似文献   

18.
<正> A crocodilian specimen is described and identified, as a new species of Alligalor in present paper. The material was collected from the Middle Member of the Shanwang Formation, Linqu County, Shandong Province by the members of the Linqu Paleontological Museum in 1984. Nearly 40 taxa of fossil vertebrates, including fishes, amphibians, reptiles, birds and mammals, have been reproted from this Miocene locality since 1930's (Yian et al. 1983, Qiu et al. 1986). Within the vertebrate fauna the fossil mammals and fishes are very rich, but the other are relatively rare. This is the first record of a crocodilan from the diatomaceous quarry of Shanwang.  相似文献   

19.
Actinopterygians (ray-finned fishes) are the most diverse group of living fishes, but have a sparse Devonian fossil record restricted to low palaeolatitudes. Here we report a new actinopterygian from the Paraná Basin of Brazil, which occupied a circumpolar position in the Palaeozoic. Available geological evidence supports a Middle Devonian or older age for this taxon, which shares features of the mandibular symphysis with the latest Devonian Tegeolepis. A phylogenetic analysis resolves these two as sister taxa. This new record expands the palaeogeographic distribution of Devonian ray-fins and suggests that gaps in their fossil record might be filled by exploring poorly sampled high-latitude localities within the Malvinokaffric Realm.  相似文献   

20.
It is very interesting that the only extant marine amphibian is the marine frog, Fejervarya cancrivora. This study investigated the reasons for this apparent rarity by conducting a phylogenetic tree analysis of the complete mitochondrial genomes from 14 amphibians, 67 freshwater fishes, four migratory fishes, 35 saltwater fishes, and one hemichordate. The results showed that amphibians, living fossil fishes, and the common ancestors of modern fishes are phylogenetically separated. In general, amphibians, living fossil fishes, saltwater fishes, and freshwater fishes are clustered in different clades. This suggests that the ancestor of living amphibians arose from a type of primordial freshwater fish, rather than the coelacanth, lungfish, or modern saltwater fish. Modern freshwater fish and modern saltwater fish were probably separated from a common ancestor by a single event, caused by crustal movement.  相似文献   

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