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1.
A new species of Cambeva endemic to the Rio Ivaí basin, Upper Paraná basin, is described combining morphological and molecular data. This new species is distinguished from all congeners by characters related to the number of pectoral-fin rays, to the colour pattern of the dorsal and lateral surface of the body, to the presence of diffuse blotches in the ventral surface of body, to the presence of a pelvic-fin and pelvic girdle, to the number of odontodes in the inter-opercular and opercular patches, to the number of dorsal and ventral procurrent rays. In addition, the analysis of mitochondrial DNA sequences identified a satisfactory genetic distance between this new species and its congeners. The new species from the Rio Ivaí reinforces its characteristics as an area of endemism for fishes in the Upper Rio Paraná basin.  相似文献   

2.
Climbing perches use the tail for forward propulsion when on land. The spiny gill covers are used to obtain purchase on the substratum. Unusually amongst teleosts, the opercular and subopercular bone are not bound strongly together into a single operculum. Instead they are joined only by a thin, flexible membrane, so that the fish has two sections of the gill cover hinged separately; the opercular on the suspensorium and the subopercular on the rearmost part of the lower jaw. The gill covers open very widely and the subopercular rotates ventrally as well as laterally. Two modes of locomotion are employed. Usually Anabus adopts a near-upright posture and alternately drives the left and right spiny suboperculars into the substratum, using the tail to vault over the subopercular (which acts in the manner of a short vaulting pole). During vigorous movement the fish may leave the substratum altogether during the vault. Fatigued fish, or fish which have fallen during climbing, move on their sides, using the tail for propulsion and a single spiny opercular which is repeatedly driven into the substratum. Maximum speeds observed on land corresponded to 1.8 body lengths S?1. No evidence of involvement of the pelvic fins in locomotion was obtained; the pectorals seemed only to help in tilting the head from side to side and did not contribute significantly to forward propulsion. On mud and tree bark the fish were laterally unstable, often resting on their sides. Grassy substrata provided support and permitted a more upright posture. Slope climbing ability was restricted to 25° when climbing tree bark and 30° when climbing grass. Coupled with lateral instability these observations disqualify the species from any tree-climbing capacity. Anabas can climb vertical obstacles of at least half body length in height by pushing the head against the obstacle, using the spiny gill covers for purchase until one or other subopercular hooks over the top of the barrier. The subopercular is then used as a fulcrum for an upwards vault to clear the obstacle.  相似文献   

3.
A new species of the catfish genus Centromochlus (Auchenipteridae, Centromochlinae) is described. The new species is diagnosed by having numerous dark rounded blotches over the body and fins, dorsal‐fin spine with serrations anteriorly and smooth posteriorly, anal fin of mature males with three unbranched and seven branched rays, anterior nuchal plate absent and posterior nuchal plate not extended ventrally. The new species is described from a small stream in the Estação Ecológica Serra Geral de Tocantins, a natural reserve in the centre of the Brazilian Cerrado, close to the watershed between the Rio Tocantins and the Rio São Francisco basins. The new species is possibly the sister taxon to the recently described Centromochlus meridionalis from the upper Rio Tapajós. Those two species share with Centromochlus perugiae, from the upper Amazon and upper Paraguay, derived features associated with the modified anal fin in sexually mature males.  相似文献   

4.
内蒙古石拐群古鳕类一新属   总被引:2,自引:2,他引:0  
内蒙古石拐地区石拐群召沟组中的长腹鳍大青山鳕(新属、新种) Daqingshaniscus longiventralis gen. et sp. nov. 是在我国中侏罗世地层中发现的一比较原始的古鳕类.其头骨眶后部分短,鳃盖骨大于下鳃盖骨,背鳍位于腹鳍与臀鳍之间,腹鳍基线长,鳍条都从基部分节、远端分叉,棘鳞仅见于尾上叶,全歪型尾,鳞片呈菱形.大青山鳕既与苏联南哈萨克斯坦 Karatau 地区的 Pteroniscus 很接近,又与我国新疆的维吾尔鳕 Uighuroniscus 及西德北部的 Stadthagen 地区的 Indaginilepis 相似.  相似文献   

5.
6.
A new rajid species,Raja koreana, is described from a single adult female specimen, 735 mm in total length, collected off the southwestern coast of the Korean Peninsula. AlthoughR. koreana is included in the group of species characterized by the scapulocoracoid lacking an anterior bridge and having the postventral fenestra expanded, it is unique among the latter in possessing: pectoral girdle propterygium not extending to snout tip; rostral shaft of neurocranium narrow and thick, unsegmented base with filamentous cartilage; snout fleshy; pores of ampullae of Lorenzini densely distributed over much of ventral surface to behind cloaca; most thorns on tail directed anteriorly; tail short; a pair of longitudinally elongated black blotches on middle of dorsal surface of disc when fresh; a pair of black blotches (grayish at center) posteriorly on pectoral fins; ventral surface of dise uniformly blackish-brown, except for areas around pores.  相似文献   

7.
A new species of Astyanax from the Rio Paraguaçu basin, Bahia, Brazil, is described. This new species is distinguished from its congeners known to occur in Brazilian drainages by the presence of small bony hooks on all fins of mature males. Furthermore, the new species can be diagnosed by its colour pattern, which consists of a unique vertically elongated humeral blotch, a conspicuous dark drop‐shaped horizontal blotch over the caudal peduncle, tapering anteriorly and not extending to the median caudal‐fin rays, and by the absence of a conspicuous broad dark midlateral stripe. The new species differs further by having the greatest body depth just anterior to the dorsal‐fin origin, 32–35 perforated scales in the lateral line and a reduced number of branched anal‐fin rays (16–20). Apparently, the new species does not fit into any species complex of Astyanax. The occurrence of bony hooks on all fins of Astyanax is discussed.  相似文献   

8.
A new species of Characidae, Moenkhausia celibela, is described from the Rio Amazonas at Santarém, Rio Maraú, several localities in the Rio Tapajós, Rio Curuá‐Una, Rio Xingu and Rio Jari, all from the Amazon basin, Brazil. The new species is distinguished from its congeners, except species included in Géry's 1992 Moenkhausia lepidura group, by presenting a dark blotch on the upper caudal‐fin lobe, and the lower lobe is hyaline or light grey. Moenkhausia celibela is distinguished from the species of the M. lepidura group by the absence of a humeral spot and the presence of a roughly triangular and dark spot at the caudal‐fin base, extending posteriorly along the middle caudal‐fin rays, and distinctly separate from the spot on the upper caudal‐fin lobe.  相似文献   

9.
A new species of Gesneriaceae, Chirita maguanensis Z.Y.Li, H.Jiang & H.Xu, is described from Southern Yunnan, China. It is similar to C. eburnea Hance in its large, fleshy, white and parallel‐veined bracts, but differs by having broad and oblique leaves with a repand–crenate or crenate margin, suborbicular bracts, membranous, white calyx, purple corolla‐tube, 2‐parted lower lip of stigma and lower disc. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 269–273.  相似文献   

10.
A new record species Heterodera ripae was found in the rhizosphere soil of nettle(Urtica sp.) on the bank of the Mangniu River in Shenyang City,Liaoning Province,China.The new record species can be characterized by vulval cone bifenestrate with circular or subcircular semifenestrae,vulval slit length averaging 34.2 μm,vulval bridge mostly broad,underbridge weak,bullae absent;the second-stage larvae stylet knobs rather wide and slightly projecting anteriorly,tail length averaging 43.7 μm and hyaline region length averaging 22.3 μm.  相似文献   

11.
Wang D  Chen LJ  Duan YX 《动物学研究》2012,33(E3-4):E57-E59
A new record species Heterodera ripae was found in the rhizosphere soil of nettle (Urtica sp.) on the bank of the Mangniu River in Shenyang City, Liaoning Province, China. The new record species can be characterized by vulval cone bifenestrate with circular or subcircular semifenestrae, vulval slit length averaging 34.2 μm, vulval bridge mostly broad, underbridge weak, bullae absent; the second-stage larvae stylet knobs rather wide and slightly projecting anteriorly, tail length averaging 43.7 μm and hyaline region length averaging 22.3 μm.  相似文献   

12.
A new monotypic genus of callionymid fishes,Protogrammus, is described. The type species isCallionymus sousai Maul, 1972. The genus is distinguished from the allied generaChalinops andDiplogrammus by its free opercular flap of skin that is connected to the body in its upper half, a ventrolateral fold of skin consisting of disconnected segments, unbranched rays in the second dorsal and anal fins, and a very small preopercular spine with the formula -11. The only known species,Protogrammus sousai, is redescribed and illustrated.  相似文献   

13.
Glyptothorax pantherinus, a new sisorid catfish species, is described from the Noa Dehing River of Arunachal Pradesh, India. The new species can be distinguished from its congeners by the following combination of characters: mottled skin; a well-developed obtuse leaf-shaped thoracic adhesive apparatus with no central depression, unculiferous ridges of the apparatus not extending anteriorly onto the gular region, and the ridges uninterrupted except for the posterior-most region; one bean-shaped cream-coloured spot on either side of the dorsal-fin origin; ventral surface of the simple rays of the paired fins are plaited marginally and distally.  相似文献   

14.
Aspects of the morphology of the opercular region of siluroids (catfishes) were examined to determine the homologies of the opercular bones of loricarioid catfishes, a diverse monophyletic neotropical group. Homology of the component structures was inferred by examination of three criteria: (1) functional relations to the jaw abduction mechanism of primitive halecostome fishes; (2) positional relations to the bones of the suspensorium and the path of the preopercular laterosensory canal; and (3) pattern of development of the preopercular canal and lateral cheek plates of loricarioid catfishes. The majority of siluroids have lost one or more of the preopercular canal exit branches to the skin surface present in most primitive siluroids. A number of specializations of the canal pathway and components of the opercular series have occurred in loricariids. Trichomycterids have the preopercular canal reduced to a short branch from the pterotic. Callichthyids share the presence of a preopercular canal with primitive siluroids, but have lost the communication of the canal between the preopercle and pterotic bones. Callichthyids and scoloplacids share one additional loss of a preopercle exit. The second of two subopercular elements of astroblepids is homologous with the interhyal. Astroblepids and loricariids have lost one additional preopercle exit, the interoperculo-mandibular ligament and the corresponding biomechanical couple for lower jaw abduction. Loricariids have probably lost the interopercle as well. These derived features of loricariids and astroblepids are viewed as specializations for a particular feeding behaviour: scraping algae and detritus from the substratum.  相似文献   

15.
宁夏中卫纳缪尔期古鳕类化石一新属   总被引:3,自引:0,他引:3  
记述了产于宁夏中卫县石炭纪纳缪尔期地层的古鳕类化石一新属新种——潘氏黄河鳕(huanghelepis pani gen.et sp.nov.)。新属种的个体中等大小,体形狭长,头长约为体长的1/6左右。颌悬挂很倾斜,具有长而窄的梯形鳃盖骨、相对较大的下鳃盖骨。全身覆鳞,体侧各有一列高度远大于宽度的长方形侧线鳞。这是在中国石炭纪地层中古鳕类化石的首次描述。  相似文献   

16.
The status of the trematode Aponurus laguncula Looss, 1907 in the western Mediterranean is re-assessed by means of a comparative morphological study and rDNA sequences based on newly collected material. A. laguncula (sensu stricto) is redescribed from Trachinus draco L. and a new cryptic species of the ‘A. laguncula complex’, Aponurus mulli n. sp., is described on the basis of abundant material from Mullus barbatus L. (type-host) and M. surmuletus L. off the Spanish Mediterranean coasts. The new species is differentiated from A. laguncula (sensu stricto) by its: significantly larger, elongate body, with maximum width at the level of the ventral sucker; shorter forebody; distinctly larger sinus-sac, seminal receptacle and seminal vesicle, with the latter also being more elongate; vesicular pars prostatica; more anteriorly located vitellarium, which consists of eight globular follicles; and distinctly smaller eggs, which are also smaller in relation to body size and have both their opercular and anopercular poles rounded. The variability and the allometric growth of the morphological characters in the new species were studied in detail, resulting in additional distinguishing features. Sequences of the large subunit rRNA (28S) gene (domains D1–D3) and ITS2 rRNA gene region for the new species have been submitted to GenBank in order to enhance future studies on species differentiation within the ‘A. laguncula complex’.  相似文献   

17.
四足动物的起源是生物进化过程中的关键问题之一。2006年,美国学者Daeschler E B和Shubin N H在加拿大努纳武特地区南部的埃勒斯米尔岛上发掘了一系列距今3.75亿年的Tiktaalik鱼化石。该鱼与希望螈(Elpisto-stegalian)一样均没有背鳍、没有鳃盖、子鳃盖、外肩胛骨;而具有宽大的背腹性明显的扁平颅骨,以及位于颅骨背面的眼睛,还具有成对的额骨、微鼻孔和位于末端的口,并具备了四足动物的一些特征,诸如较大的通气孔、可活动的颈部、伏瓦状排列的肋骨,胸鳍出现了挠骨的分化,并有骨质关节。这一发现填补了从海洋动物到四足动物的空白。  相似文献   

18.
Hemiodus iratapuru, a new species of the Hemiodontidae from the Rio Iratapuru, a left bank tributary of the Rio Jari, Amazon Basin, Brazil, is described. The new species is diagnosed from other species of Hemiodus by modifications in the ectopterygoid, tooth form, scale counts, dorsal‐fin form and colour pattern. The new species is proposed to be related to the Hemiodus quadrimaculatus species group.  相似文献   

19.
A new species of Parotocinclus is described from the Rio Mamanguape basin, in the State of Paraíba, north-eastern Brazil. The new species can be distinguished from all of its congeners, except for P. bahiensis, P. cesarpintoi, P. jumbo, P. nandae and P. spilosoma, by the presence of an abdomen covered by a few small and dispersed platelets (vs. an abdomen entirely covered by large plates in adult individuals or the absence of plates in that region). The new species differs from those mentioned above with respect to several features, such as an exposed pectoral girdle and supporting odontodes medially and laterally, the number of premaxillary and dentary teeth, odontodes covering only the lateral portion of the cleithrum and the absence of irregular golden lines on the head and body (colour in vivo). The new species was collected only in the upper and middle portions of the Rio Mamanguape basin, suggesting a geographic distribution restricted to the Caatinga biome.  相似文献   

20.
A new species of Anoplodiscus (Monogenea, Anoplodiscidae), parasitic on gills of the red porgy, Pagrus pagrus, from the coastal zone of the State of Rio de Janeiro, Brazil, is described and illustrated. The new species can be differentiated from the other species of this genus by the shape of the accessory piece of the copulatory complex, and the length of the vagina. This is the first record of a species of Anoplodiscus in the Neotropical region.  相似文献   

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