首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 531 毫秒
1.
Spadella, M.A., Oliveira, C. and Quagio‐Grassiotto, I. 2009. Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes). —Acta Zoologica (Stockholm) 91 : 373–389. Siluriformes comprises the most diverse and widely distributed ostariophysan group, a fish assemblage that includes about three quarters of the freshwater fish of the world. In this study, the ultrastructural characterization of spermiogenesis and spermatozoa in specimens of Copionodontinae (the sister group to all other trichomycterids), Trichomycterinae (a derived trichomycterid group), and Ituglanis (a genus not assigned to any trichomycterid subfamily) is presented. The comparative analyses of the data show that trichomycterid species share six of seven analyzed spermiogenesis characters, reinforcing the monophyly of the group. Analyses of trichomycterid sperm ultrastructure showed that the species studied share the same character states for nine of seventeen characters analyzed. Copionodon orthiocarinatus and Ituglanis amazonicus each share more ultrastructural characters with species of Trichomycterus than with one another. Regarding the families of Loricarioidea, the species of Trichomycteridae share more characters of spermatogenesis, spermiogenesis, and sperm with representatives of the families Callichthyidae, Loricariidae, and Scoloplacidae than with Nematogenyidae, its hypothesized sister group. With the exception of the family Nematogenyidae, the character similarities observed reinforce the monophyly of the superfamily Loricarioidea.  相似文献   

2.
Trichomycteridae is a well‐corroborated catfish family that comprises about 300 valid species distributed in eight subfamilies. The phyletic status of the Trichomycterinae is uncertain, with different hypothesis regarding the position of the miniaturized Trichomycterus hasemani group. This group comprises four valid species, and neither its monophyly nor its positioning among the Trichomycteridae was tested in a phylogenetic framework. Bayesian Inference and Maximum Likelihood analyses of a molecular data set comprising the mitochondrial genes 12S and 16S and the nuclear genes H3, MYH6 and RAG2 (2983 bp) for 26 taxa highly supported the miniature catfish T. hasemani group as monophyletic and sister to the Tridentinae, consequently recognized as a new genus of this subfamily. Potamoglanis gen. nov. is diagnosed by seven character states: an angle of 35–40° between the main longitudinal axis of the head and the main axis of the autopalatine; thin tubular shape of the second ceratobranchial; presence of six or seven anal‐fin rays; eyes dorsally placed on head; opercular and interopercular odontodes patches not juxtaposed; absence of a distal process on the hyomandibula and presence of a long process on the anterior region of the hyomandibula. Potamoglanis gen. nov is similar to the Tridentinae genera by the presence of a wide cranial fontanelle; presence of a short ventral process in the opercular bone and by the origin of the dorsal fin placed in a vertical through the anal‐fin origin.  相似文献   

3.
The internal phylogenetic relationships of the ichneumonid subfamily Labeninae (Hymenoptera) are re‐assessed using 136 characters for 54 species representing all currently known species‐groups. New character sets are used. These include a new form of seta (named the grossulariform setae) which are present on the inner surface of the hind coxa of some females, and the extensive structural modifications of the terminal segments of the female metasoma, which are described and structural homologies established. The monophyly of the Labeninae and of the four component tribes, Groteini, Poecilocryptini, Xenothyrini and Labenini, is demonstrated. The Groteini is shown to be the sister‐group to the Poecilocryptini + (Xenothyrini + Labenini). Monophyletic genera are established, including three new genera: Ozlabium gen. nov. Gauld & Wahl (type‐species 0. arcadium sp. nov.) in the Groteini from Australia; Torquinsha gen. nov. Gauld & Wahl (type‐species Certonotus invictus Porter) in the Labenini from Chile, and Gauldianus gen. nov. Lanfranco (type‐species Gauldianus chilensis sp. nov. Lanfranco) in the Labenini from Chile. Apechoneura is removed from synonymy and re‐instated as a valid genus for a complex of tropical American species. The biogeographic patterns shown by the Labeninae are discussed. Evidence suggests that the group radiated on Gondwanaland after the separation of Africa/India/Madagascar, but prior to the separation of Australia. Species occurring off the southern continental fragments, in North America, are shown to be members of highly derived lineages, a result consistent with the hypothesis that labenines colonized North America recently through Mesoamerica. Patterns of host utilization and mating behaviour are examined for the group. Members of the more derived lineages show progressively more female specializations for attacking hosts deeply concealed in woody substrates. Males in the more specialized lineages are shown to have a wider array of secondary sexual characteristics and genitalic ornamentations than more plesiomorphic taxa.  相似文献   

4.
A male specimen of a new strepsipteran genus and species ( Protoxenos janzeni gen. et sp. nov.) and family (Protoxenidae fam. nov.) found in Baltic amber is described and illustrated. It shows features which are apparently more plesiomorphic than in hitherto known strepsipterans, such as laterally inserted eight-segmented antennae, very robust mandibles with a broad base, a prominent galea, a comparatively short, transverse metapostnotum, hindwings that are feebly extended in a rostrocaudal direction, and equally sclerotized abdominal tergites and sternites. Based on a cladistic analysis of 46 characters of males of 11 genera and three outgroup taxa, P. janzeni is the sister group of all other known strepsipterans, and Mengea the sister group of Strepsiptera s.s . Eoxenos is the sister group of the remaining extant strepsipterans and Mengenillidae is therefore paraphyletic. Newly established groundplan features of Strepsiptera will facilitate the clarification of the systematic position of the Order in future studies.  相似文献   

5.
A new genus and species of scombrid fish Caucombrus histiopterygius gen. et sp. nov. is described from the Lower Oligocene (Lower Maikopian, Pshekha regional state) of the north-western Caucasus (Russia) and Abkhazia (rivers Belaya, Pshekha and Gumista). The new taxon differs from the other known Scombridae, both fossil and Recent, by the high and sail-like first dorsal fin. Osteological characters of Caucombrus gen. nov. indicate its relationship with the Spanish mackerels (subfamily Scomberomorinae). It is assumed that either C. histiopterygius gen. et sp. nov. or the related species of Caucombrus gen. nov. inhabited the Mid-Oligocene sea basin in the territory of the Rhine Graben (Germany).  相似文献   

6.
A new subfamily of ichneumon wasps, Labenopimplinae subfam. nov. (Ichneumonidae), is described from the Cenomanian Ola Formation of the locality Obeshchayushchiy, Magadan Region, Russian Far East. The subfamily is highly diverse morphologically and combines characters of the Labeninae and Pimplinae. It includes 11 new species described in five new genera: Labenopimpla rasnitsyni gen. et sp. nov., L. kasparyani sp. nov., Armanopimpla zherikhini gen. et sp. nov, Ramulimonstrum intermedium gen. et sp. nov., Rugopimpla vulgaris gen. et sp. nov., R. fallax sp. nov., R. angusticella sp. nov., R. macra sp. nov., R. matrona sp. nov., Micropimpla lucida gen. et sp. nov., and M. obscura sp. nov. Also described is a new monotypic genus, Tryphopimpla xoridoptera gen. et sp. nov., which combines characters of the Tryphoninae, Pimplinae, and Xoridinae and cannot be currently placed into any of the known subfamilies. The population of fossil ichneumon wasps at this locality is distinctly dominated by females.  相似文献   

7.
早寒武世马哈螺类的骨骼化特征、分类和演化意义   总被引:3,自引:0,他引:3  
马哈螺类(maikhanellids)是已知最古老的单板类,以往缺乏系统研究,并在分类上争议较大,文中以滇东早寒武世梅树村阶微小骨骼化石的丰富材料为依据,详细阐述该类群的形态特征和超微结构,探讨其亲缘关系和演化趋势,研究表明,马哈螺类由6个属组成,包括Maikhanella,Ramenta,Ramentoides gen.nov.,Mediata gen.nov.,Yunnanopleure和Purella。各属之间壳形变化较大,但裸露的壳顶和普遍发育的鳞片状或条状突起表明它们在明显的亲缘关系,并显示两个演化方向,即Maikhanella Ramentoides gen.nov.Ramenta和Maikhanella Mediata gen.nov.Yunanopleura-Purella。马哈螺类分布于梅树村期早,中期,Maikhanella是最原始的马哈螺,最先出现在梅树村阶小歪头山段,也是中谊村段下磷矿层唯一的马哈螺,而在该段上磷矿层马哈螺类发生了明显的属种分异,在大少段所有的马哈螺类突然消失,马哈螺类的壳体曾被描述为:骨针状的外骨骼”,“骨片状外骼”和“包裹在中间基质中的骨针”,但当前研究表明,以Maikhanella pristinis和Ramenta cambrina为代表的马哈螺类的内壳层具有早期单板类中较常见的水平交错纤状结构,指示了马哈螺类具有致密成层的壳壁,文中新建2亚科,2属和5种,即Maikhanellinae subfamily nov.,Purellinae subfamily nov.,Maikhanella Perelegans sp.nov.,Ramenta superata sp.nov.,Ramentoides latispinus gen.et sp.nov.,Mediata kunyangensis gen.et sp.nov.,Yunnanopleura longidens sp.nov。  相似文献   

8.
中国东北晚侏罗世虻类化石(昆虫纲:双翅目)   总被引:5,自引:0,他引:5  
本文论述了辽宁西部上侏罗统虻类6个科的化石,包括1新科,10个新属和15个新种。其中Palaepangonius eupterus gen.et sp.nov.,Elpangonius pletus gen,et sp.nov.和Allomyia ruderalis gen.et sp.nov.均属于虻科(Tabanidae);Orsobrachyceron chinensis gen.et sp  相似文献   

9.
A new fossil digger wasp Rovnoecus klesovicus gen. et sp. nov. (Hymenoptera, Crabronidae, Pemphredoninae, Pemphredonini) is described from the Upper Eocene Rovno amber. The genus Rovnoecus gen. nov. is characterized by an incomplete occipital carina, partly reduced second discoidal cell, and the presence of spines on all tibiae. Rovnoecus gen. nov. is most similar to the fossil genus Eoxyloecus Budrys, 1993 from the Baltic amber. The two genera form a monophyletic group that is a sister group to the group formed by the genera Passaloecus Shuckard, 1837 and Eopinoecus Budrys, 1993. This indirectly corroborates the hypothesis of the geographically different origin of the Rovno and Baltic ambers.  相似文献   

10.
11.
描述产自辽宁北票上园地区黄半吉沟上侏罗统义县组下部膜翅目昆虫化石1新属新种Trematothoracoides liaoningensis gen.et sp.nov.,归入薤式产(Sepulcidae)中的陷胸茎蜂亚科(Trematothoracinae)。这是首次在我国发现可行的陷胸茎蜂化石,也是该亚科在侏罗纪的产次报道,分支分析结果表明Trematothoracinae为一单系类群。Thoracotrema与Prosyntexis进化程度较高,构成一对姊妹群,同时又是Trematothorax的姊妹群,Trematothoracoides最为原始,为Thoracotrema Prosymtexis Trematothorax的姊妹群。  相似文献   

12.
描述产自辽宁北票上园地区黄半吉沟上侏罗统义县组下部膜翅目昆虫化石1新属新种Trematothoracoides liaoningensis gen. et sp. nov., 归入葬茎蜂科(Sepulcidae)中的陷胸茎蜂亚科(Trematothoracinae)。这是首次在我国发现可靠的陷胸茎蜂化石,也是该亚科在侏罗纪的首次报道。分支分析结果表明Trematothoracinae为一单系类群。Thoracotrema与Prosyntexis进化程度较高,构成一对姊妹群,同时又是Trematothorax的姊妹群;Trematothoracoides最为原始,为Thoracotrema+Prosyntexis+Trematothorax的姊妹群。  相似文献   

13.
A new tribe of digger wasps, Protomicroidini trib. nov. (Hymenoptera, Crabronidae), including a single known species Protomicroides sororius gen. et sp. nov. is described from the Upper Eocene Rovno amber, Ukraine. The new tribe combines features characteristic of several tribes of the Crabroninae and is a sister group of the extant tribe Oxybelini. The most distinctive characters of the new tribe include nonelongate propodeum with strongly developed lateral keel and enclosed dorsal area; semioval postscutellum with a lamellate border; absence of pygidial plate, psammophores, and digging tarsal rakes; and considerably reduced forewing venation.  相似文献   

14.
Euryte koreana sp. nov. is described from the shallow littoral on the East Coast of South Korea, and represents the first record of the subfamily Euryteinae Monchenko, 1974 in the Pacific Ocean north of the tropics. It belongs to a group of species that have the caudal rami length/width ratio of around four, but differs from all congeners by a number of morphological features. Detailed drawings and extensive scanning electron micrographs of many characters of ornamentation provided for this species should serve as a benchmark for distinguishing closely related species in this subfamily with conservative macro-morphology. A morphologically distinct population from anchialine caves in Mallorca, identified previously as Euryte longicauda Philippi, 1843, is described as another new species: Euryte jaumei sp. nov. To test the phylogenetic relationships of its members and previous hypotheses about generic placement of two species associated with scleractinian corals, several cladistic analyses are performed on all 16 currently recognized species of Euryteinae and two outgroups, Neocyclops australiensis Karanovic, 2008 and Troglocyclops janstocki Rocha and Iliffe, 1994, using 25 morphological characters. All resulting trees suggest a close relationship between the two commensal species and them as a sister clade to all other Euryteinae. They are transferred into a newly erected genus Coraleuryte gen. nov., as C. bellatula (Humes, 1991) comb. nov. and C. verecunda (Humes, 1992) comb. nov., and a revised diagnoses is provided for the genus Euryte Philippi, 1843. Obtained cladograms also show that Ancheuryte Herbst, 1989 is nested deeply within the Euryte clade, so the genus is synonymized and its only species is transferred, as E. notabilis (Herbst, 1989) comb. nov. A key to species of Euryteinae is also provided.  相似文献   

15.
The subfamily Typhlocybinae is a ubiquitous, highly diverse group of mostly tiny, delicate leafhoppers. The tribal classification has long been controversial and phylogenetic methods have only recently begun to test the phylogenetic status and relationships of tribes. To shed light on the evolution of Typhlocybinae, we performed phylogenetic analyses based on 28 newly sequenced and 19 previously sequenced mitochondrial genomes representing all currently recognized tribes. The results support the monophyly of the subfamily and its sister‐group relationship to Mileewinae. The tribe Zyginellini is polyphyletic with some included genera derived independently within Typhlocybini. Ancestral character state reconstruction suggests that some morphological characters traditionally considered important for diagnosing tribes (presence/absence of ocelli, development of hind wing submarginal vein) are homoplastic. Divergence time estimates indicate that the subfamily arose during the Middle Cretaceous and that the extant tribes arose during the Late Cretaceous. Phylogenetic results support establishment of a new genus, Subtilissimia Yan & Yang gen. nov., with two new species, Subtilissimia fulva Yan & Yang sp. nov. and Subtilissimia pellicula Yan & Yang sp. nov.; but indicate that two previously recognized species of Farynala distinguished only by the direction of curvature of the processes of the aedeagus are synonyms, that is, Farynala dextra Yan & Yang, 2017 equals Farynala sinistra Yan & Yang, 2017 syn. nov. A key to tribes of Typhlocybinae is provided.  相似文献   

16.
The oldest webspinners, Sinembia rossi gen. et sp. nov. and Juraembia ningchengensis gen. et sp. nov. , are described in the new family Sinembiidae fam. nov. from the Middle Jurassic of Inner Mongolia, China. They differ from the Cretaceous and more recent Embiodea in several plesiomorphic characters, namely they have a long ovipositor, three‐segmented cerci, eyes situated on the posterolateral angles of the head, and the prothoracic prescutum is absent: these characters suggest habits that strongly differ from those of the recent taxa. The loss of the ovipositor and the reduction in the number of cerci can no longer be considered as synapomorphies of the ((Embiodea + Zoraptera) + Plecoptera) and (Embiodea + Zoraptera) clades, respectively.  相似文献   

17.
A stichaeid fish, Xenolumpenus longipterus gen. et sp. nov., is described on the basis of 2 specimens (107.1–114.9 mm in standard length) collected from 167 to 300 m in the northern Sea of Japan off southern Hokkaido, Japan. Xenolumpenus is unique among all known genera of the subfamily Lumpeninae in having all pectoral, pelvic, and anal fin rays elongate and unbranched with fin membranes well-incised. Xenolumpenus longipterus can be further distinguished from all species of the subfamily in having the following combination of characters: dorsal fin XLVI–XLVIII; anal fin II, 28–29; pectoral fin 11; large black blotches on pectoral fin; and black ocellus on caudal fin.  相似文献   

18.
Forty‐six characters, mostly of the thoracic pleuron, are proposed for the reconstruction of the phylogenetic relationships among the major groups of the family Phoridae. Analysis of these characters, in conjunction with the pre‐existing suite of morphological characters from other body parts, provides a basis for a strongly supported new classification of the Phoridae, in which Sciadocerinae is the sister group of ((Chonocephalus Wandolleck & Cyphocephalus Borgmeier) + (Termitoxeniinae + (Metopininae + Phorinae s.l.))). A new subfamily, Chonocephalinae subfamily nov. , is proposed for Chonocephalus and Cyphocephalus, and a new genus, Hirotophora gen. nov. , is proposed for Chaetopleurophora multiseriata (Aldrich) ( comb. nov. ). © 2015 The Linnean Society of London  相似文献   

19.
Hybodontoid and nonhybodontoid sharks are described from the Lower Triassic Vega‐Phroso Siltstone Member of Sulphur Mountain Formation on the basis of newly discovered material. The age of the classic fossil site ‘Wapiti Lake’ in the Canadian Rocky Mountains is discussed on the basis of new field data and one conodont found in association. Preliminary results suggest that these elasmobranch remains are between early Smithian and Spathian in age. Apart from the enigmatic genus Listracanthus and previously reported edestoids, the shark fauna consists of at least one hybodont, at least two questionable hybodontoid genera and an elasmobranch of enigmatic affinities, represented by peculiar denticles only and described as ‘genus A’incertae sedis. The presence of the only previously reported hybodont genus, cf. Palaeobates, is erroneous. The largest specimen represents the most complete Early Mesozoic shark known. The heterodonty of its dentition, fin spine morphology and the short, robust body shape imply it represents a member of a new family of shark, Wapitiodidae fam. nov. , and is described here as Wapitiodus aplopagus gen. et sp. nov. The unique dental morphology shows affinities to Polyacrodus but clearly differs in the complete lack of side cusps. Wapitiodus gen. nov. possesses a primitive fin spine structure. The tooth crowns are entirely blunt in the distal (posterior) tooth files, and are acuminate‐unicuspid in several anterior files. Tooth morphology, the shape of the basal cartilages, the proximal insertion of the fin spines and the pectoral fin structure are interpreted as diagnostic characters for this new genus, and possibly for the Wapitiodidae fam. nov. The majority of observed characters appear to be primitive and are reminiscent of Palaeozoic sharks, however, and these features include dorsal fin spine morphology and gross skull anatomy. A second species, provisionally placed in the same genus, is described as Wapitiodus homalorhizo sp. nov. Wapitiodus homalorhizo sp. nov. can be distinguished from W. aplopagus gen. et sp. nov. by the proportions of the fin spines, tooth morphology and possibly the body shape. Several isolated teeth and other fragmentary material are referred to either Wapitiodus gen. nov. sp. indet. or to ?Polyacrodus sp. (Polyacrodontidae gen. et sp. indet.). A third genus of elasmobranch (incertae sedis) is described as ‘Genus A’ and is recognized by its peculiar scales. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 149 , 309–337.  相似文献   

20.
Alectrias mutsuensis sp. nov. is described on specimens collected from Mutsu Bay, Aomori Pref. This new species is rather deep dweller compared to other species of the genus, living on muddy bottoms, about 20 to 40 meters deep, and is diagnosed by the following characters: dermal crest on head reaching to occipital region; distance between end of dermal crest and dorsal fin origin less than eye diameter; end of anal fin separated from caudal fin; anterior dorsal spines before anal origin, slender and flexible; epaxial hypurals mostly fused into a single plate. A key to all nine species belonging to the subfamily Alectriinae is presented.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号