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1.
记述了产自广西南宁盆地渐新世早—中期的鲤科鲤亚科一新属种——伍氏南宁鲤(?Nanningocyprinus wui gen.et sp.nov)。化石材料包括一些咽喉骨和咽齿。这些咽喉骨和咽齿的以下特征组合明显不同于其他鲤科鱼类:齿式—3·2·1,主行第一枚咽齿大小是第二枚的3~4倍,第二枚咽齿及第二行第一枚咽齿咀嚼面上各仅有一条沟纹,咽骨前角很发育。该属种的发现进一步证明鲤亚科是鲤科中较早的分支,中国南方很有可能是鲤亚科的起源和分化中心。  相似文献   

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3.
本文记述了发现在乌兰塔塔尔地区的中渐新世圆柱齿鼠科化石。根据牙齿特征,将乌兰塔塔尔动物群中原先的阿尔丁鼠(Ardynomys)和圆柱鼠(Cyclomylus)分别放到异鼠(Anomoemys)和察干鼠(Tsaganomys)属中,将原“小圆柱鼠”(Cyclomylus minutus Kowalski,1974)改订为小察干鼠(Tsaganomys minutus)。在记述洛异鼠(Anomoernys lohiculus)、阿尔泰察干鼠(Tsaganomys altaicus)和小察干鼠的同时,讨论了它们的种内变异。此外还对察干鼠和圆柱鼠的齿冠和齿根关系问题做了初步探讨。  相似文献   

4.
浙江长兴早三叠世裂齿鱼类一新属   总被引:2,自引:0,他引:2  
报道发现于浙江长兴全球二叠-三叠系界线层型剖面下三叠统殷坑组下部的一类裂齿鱼化石--长兴副裂齿鱼(新属、新种)Paraperleidus changxingensis gen.etsp.nov.,其左、右鼻骨在中间相接,独特的前鳃盖骨形状、位置以及宽长的膜质翼耳骨等特征,可区别于其他属。  相似文献   

5.
记述了在内蒙古阿左旗乌兰塔塔尔早渐新世乌兰塔塔尔组中发现的鬣齿兽一新种——内蒙古鬣齿兽(Hyaenodon neimongoliensis sp.nov.)。新种在大小和特征上与Hyaenodonpervagus相近或相似,但它的pl为单齿根,前面的下前臼齿之间有齿隙,下颊齿无舌侧齿带。  相似文献   

6.
甘肃临夏盆地的渐新世巨犀化石   总被引:3,自引:2,他引:3  
描述了 2种巨犀化石 :霍尔果斯准噶尔巨犀 (Dzungariotheriumorgosense)和牙沟副巨犀(新种 ) (Paraceratheriumyagouensesp .nov.)。新种的主要特征是 :个体小 ;上颊齿齿冠高 ,有薄层白垩质覆盖 ;DP2~M1反前刺大 ,原尖后收缩沟明显 ,次尖有深的前收缩沟 ,中谷和后凹中常有附属小柱等。巨犀的演化历史可能比过去想象的更复杂。Indricotherium、Dzungariotherium和Paraceratherium为代表不同进化水平和支系的 3个属 ,不应合并为Paraceratherium一属。牙沟含巨犀化石层位的地质时代为晚渐新世。  相似文献   

7.
林英任  项存悌 《菌物系统》1999,18(4):357-360
在安徽省黄山杜鹃〗Rhododendron maculiferum Franch.ssp.anhweiense (Wils.)Chamb.〖上发现盘菌纲一新属--新齿裂菌属(NHeococcomycesY.R.Lin,C.T.Xiang&Z.Z.Li).对该属及其模式种--杜鹃新齿裂菌(N.rhododendri Y.R.Lin,C.T.Xiang&Z.Z.Li)进行了描述和讨论。主模式标本存放在  相似文献   

8.
在安徽省黄山杜鹃[Rhododendronmaculiferum Franch.ssp.anhweiense(Wils.)Chamb.]上发现盘菌纲一新属──新齿裂菌属(NeococcomycesY.RLin,C.T.Xiang&Z.Z.Li)。对该属及其模式种──杜鹃新齿裂茵(NrhododendriY.RLin,C.T.Xiang&Z.Z Li)进行了描述和讨论。主模式标本存放在安徽农业大学森林保护教研室(AAUFP).  相似文献   

9.
在安徽省黄山杜鹃[Rhododendronmaculiferum Franch.ssp.anhweiense(Wils.)Chamb.]上发现盘菌纲一新属──新齿裂菌属(NeococcomycesY.RLin,C.T.Xiang&Z.Z.Li)。对该属及其模式种──杜鹃新齿裂茵(NrhododendriY.RLin,C.T.Xiang&Z.Z Li)进行了描述和讨论。主模式标本存放在安徽农业大学森林保护教研室(AAUFP).  相似文献   

10.
描述了在兰州盆地渐新统韩家井组底部的黄砂层中新发现的巨犀化石:黄河巨犀(Paraceratherium huangheense sp.nov.)(新种),该化石产出层位的古地磁年龄为距今31.5Ma。新种主要特征为:P2之前无齿槽痕迹,一对下门齿粗壮,互相靠近,向前平伸且略微上翘,下颏孔位于p3之下,水平支下缘平直,p2前的齿隙部分向上隆起,下颌角圆钝,上升支后缘斜向后上方,齿式:?·?·3·3/1·0·3·3。除个体较大、下颌后缘有所不同之外,其下颌的总体特征与巴基斯坦的Paraceratherium bugtiense最为接近,显示两者可能具有较近的亲缘关系。新标本的发现为确定经典的Dera Bugti地点产大巨犀化石层位的年代提供了新的证据,并为青藏高原的隆升讨论提供了新的哺乳动物化石证据。  相似文献   

11.
An extra fourth row of pharyngeal teeth was found on both pharyngeal arches in a specmen of the small African barb, Barbus paludinosus , a species normally exhibiting three rows of pharyngeal teeth. Possible phylogenetic significance of this alteration is discussed in connection with occurrence of extra fourth rows of pharyngeal teeth in other cyprinid lineages.  相似文献   

12.
根据产自广西南宁盆地渐新世早-中期的鳅科鱼类眼下刺化石建立了鳅属新种:南宁鳅+Cobitis nanningensis sp.nov.。眼下刺长1.8~3.0 mm,粗细适中,刺二分叉,侧后突较中后突短而细,长度约为中后突长的1/3,侧突发育。这些眼下刺与德国晚渐新世的+Cobitis primigenus最为相似,但又以侧突更为发育而与之区别。这是迄今最早的鳅科化石记录,为了解早期鳅科鱼类的分布和眼下刺的形态特征提供了有益证据。南宁鳅及德国晚渐新世的+C.primigenus揭示,渐新世时期鳅科鱼类已广布于欧亚大陆。  相似文献   

13.
A new species of cyprinid fish, Mekongina lancangensis, is described from the upper Mekong River drainage in Southern Yunnan, China. The new species is distinguished from the other species of Mekongina occurring in the lower Mekong River drainage by possessing the following combination of characters: one pair of rostral barbels; two rows of tubercles irregularly scattered on the snout and cheeks, with two enlarged tubercles present at each side of anterior of the snout; 19–27 rostral marginal lappets; lateral line with 38–41 scales; 5·5 or 6·5 scales in transverse series from dorsal‐fin origin to lateral line; 18–20 circumpeduncular scales; snout length 31·9–36·9% head length; tip of depressed anal‐fin rays extending to the caudal‐fin base.  相似文献   

14.
Capoeta is a herbivorous cyprinid fish genus, widely distributed in water bodies of Western Asia. Recent species show a distinct biogeographic pattern with endemic distribution in large fluvial drainage basins. As other cyprinids, the species of this genus are characterized by the presence of the pharyngeal bone with pharyngeal teeth. Despite this, the detailed morphology of the pharyngeal teeth, its interspecific and topologic variations, and the importance for taxonomy and phylogeny of the genus Capoeta are still not established. For the first time, a detailed comprehensive study of the pharyngeal dentition of 10 Capoeta species has been provided. The morphologic study of the pharyngeal dentition bases on the 3D microtomography and follows the purpose to evaluate the potential taxonomic and phylogenetic signals of these elements, as well as to study interspecific and topologic variations of the pharyngeal teeth. In this study, we propose a new methodology to categorize the studied pharyngeal teeth in 18 shape classes. The results of this study show that the detailed 3D morphology of the pharyngeal teeth is a useful tool for the identification of isolated teeth at the generic and/or specific level and that in certain cases, the tooth position in the teeth rows can be identified. Additionally, the preliminary analysis shows that the morphology of the pharyngeal teeth provides a potential phylogenetic signal. Both these patterns are very important for the taxonomy of cyprinid fishes and especially can be applied to fossil records.  相似文献   

15.
We studied the morphology and shape variation of the palatal organ and chewing pad of sucker fishes, family Catostomidae. The palatal organ is a muscularized structure that forms a large mass on the roof of the posterior part of the buccopharyngeal cavity in cypriniform fishes. It functions in coordination with the branchial arches to separate food items from inorganic debris during feeding. The palatal organ exhibits considerable variability in morphology among catostomids. It is shorter, narrower, and thinner in species of the subfamily Cycleptinae (e.g., Cycleptus elongatus) than in other catostomid subfamilies. The thickest and widest palatal organ is seen in species of the subfamily Ictiobinae (e.g., Ictiobus cyprinellus). The shape and size of the palatal organ generally varies between these extremes in species of subfamily Catostominae (e.g., Catostomus and Moxostoma species). Principal components analysis and analysis of variance has differentiated means of various palatal organ measurements for each monophyletic subfamily and tribe of Catostomidae with statistical significance. These results corroborate previously established typological classification of catostomids based on pharyngeal tooth count, pharyngeal tooth morphology, and diet. A keratinized chewing pad forms on the posterior surface of the palatal organ in catostomids or on a skeletal process in cyprinids and serves as an occlusion surface for pharyngeal teeth. The chewing pad is lunate in catostomids and generally ovoid in cyprinids. It is absent from the species of loaches (e.g., botiids, cobitids, and nemacheilids) and gyrinocheilids examined. A synonymy of terms used in the past to describe the palatal organ and chewing pad of Cypriniformes is provided. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.  相似文献   

16.
Skeletal elements of the gill arches of adult cypriniform fishes vary widely in number, size, and shape and are important characters in morphologically based phylogenetic studies. Understanding the developmental basis for this variation is thus phylogenetically significant but also important in relation to the many developmental genetic and molecularly based studies of the early developing and hence experimentally tractable gill arches in the zebrafish, a cyprinid cypriniform. We describe the sequence of the chondrification and ossification of the pharyngeal arches and associated dermal bones from Catostomus commersonii (Catostomidae, Cypriniformes) and make selected comparisons to other similarly described pharyngeal arches. We noted shared spatial trends in arch development including the formation of ventral cartilages before dorsal and anterior cartilages before posterior. Qualitatively variable gill arch elements in Cypriniformes including pharyngobranchial 1, pharyngobranchial 4, and the sublingual are the last such elements to chondrify in C. commersonii. We show that the sublingual bone in C. commersonii has two cartilaginous precursors that fuse and ossify to form the single bone in adults. This indicates homology of the sublingual in catostomids to the two sublingual bones in the adults of cobitids and balitorids. Intriguing patterns of fusion and segmentation of the cartilages in the pharyngeal arches were discovered. These include the individuation of the basihyal and anterior copula through segmentation of a single cartilage rod, fusion of cartilaginous basibranchials 4 and 5, and fusion of hypobranchial 4 with ceratobranchial 4. Such “fluidity” in cartilage patterning may be widespread in fishes and requires further comparative developmental studies. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

17.
A new barbine cyprinid fish, Acrossocheilus multistriatus sp. nov., is described from the Zhujiang River(Pearl River) basin in South China. It is separated from all other barred congeners except A. monticola by its unique coloration pattern of 8–12 vs. 5–7 vertical dark bars on the dorsum and flank. Although 8 vertical black bars are also present in specimens of A. monticola, the new species is distinct from it by having a well-developed(vs. poor-developed) lower lip, with or without a median interruption(vs. with a median interruption which wider than 1/2 mouth width) on lower jaw, the lower jaw entirely covered(vs. uncoverd) by the lower lip, body depth 22.57%–25.22% SL(vs. 25.64%–32.26% SL). Additional characteristices as follows: last simple dorsal-fin ray soft without serration; dark stripes on membranes between dorsal-fin rays; dark stripes absent on membranes between anal fin rays; maxillary barbels longer than eye diameter, extending to posterior edge of eyes.  相似文献   

18.
The genus Calocedrus Kurz is characterized by flattened branches covered with decussate and dimorphic leaves. In this study, we describe fossil foliage of Calocedrus discovered in the Shangcun Formation (early Oligocene) of the Maoming Basin, South China. The fossils have wedge‐shaped branchlet segments and scale‐like strongly dimorphic leaves, similar to the fossil species Calocedrus lantenoisi (Laurent) Tao. There have been no detailed studies of the morphological features and cuticle structures of C. lantenoisi. Therefore, a newly emended diagnosis of the species C. lantenoisi is given based on a detailed study of leaf morphology and cuticular characters exhibited by the Maoming fossils. This is one of the earliest fossil records of Calocedrus in the world, providing additional evidence for the early biogeographic history of this genus and supporting the inference that eastern Asian Calocedrus is primitive among all the living species. The extant species of Calocedrus are mainly distributed in mountainous regions. On the basis of the “nearest living relative” analysis, we propose that the Maoming Basin was adjacent to a mountainous region during the early Oligocene.  相似文献   

19.
Sinocyclocheilus donglanensis, a new cyprinid species from a subterranean river in Donglan County in the Guangxi Zhuang Autonomous Region of southern China, is described. It is distinguished from all congeners by the following combination of characteristics: a completely scaled body with well-developed eyes; a curved lateral line possessing 57–64 scales; pectoral fin not reaching pelvic fin origin and last unbranched ray of the dorsal fin clearly serrated along its posterior edge; 8–9 predorsal vertebrae; 8–9 gill rakers; joints of dentary-angulars not close to each other at the isthmus; and a slightly inferior mouth with the upper jaw (6.2–7.4% in standard length: SL) protruding slightly beyond the lower one (5.7–6.7% SL). Sinocyclocheilus donglanensis is sympatric with the peculiarly shaped, hunchbacked S. altishoulderus.  相似文献   

20.
Six charophyte, 13 mollusc, four ostracod and nine fish otolith taxa are taxonomically described, and one fruit, one seed and two foraminiferal taxa are briefly noted from the Lower Cyrena Beds and the Lower Coloured Molasse of the Sindelsdorf section near Penzberg (approximately 50 km south of Munich). Our palaeoecological and lithological data from the Lower Cyrena Beds suggest a delta plain with lagoons, estuaries, slowly flowing rivers, lakes and swamps. Faunal and floral elements of the Lower Coloured Molasse indicate lacustrine environments. The gastropod Tympanotonos and the tropical to subtropical fish fauna (Eleotridae, Ambassidae and Cyprinodontidae) suggest a warm, at least subtropical climate. Furthermore, Tympanotonos suggests comparisons with Recent molluscan faunas of the mangrove swamps of the West African coast, and thus hints at mangrove vegetation bordering the coasts of the Upper Bavarian Molasse Sea. A biostratigraphical classification for the Oligocene Molasse deposits of the Penzberg Syncline is established for the first time based on otoliths and charophytes. The Lower Cyrena Beds are attributed to the newly defined otolith zone OT-O1/2 and probably correspond to the oldest part of the Chara microcera Zone. The lowermost part of the Lower Coloured Molasse can be correlated both with otolith zone OT-O2 and the Chara microcera Zone. The Sindelsdorf section lies within the Rupelian–Chattian transition zone and thus the chronostratigraphic age is approximately 29–28 Ma.  相似文献   

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