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1.
Aspects of the biology of the Natal mountain catfish, Amphilius natalensis, including gametogenesis, spawning season, size-at-maturity, sex ratio, diet and feeding morphology were determined from fish collected in the Songimvelo Game Reserve, South Africa, between 1989 and 1990. Female sexual maturity was established at 63 mm total length. A. natalensis is an asynchronous, iteroparous spawner, breeding throughout summer from August to February. Sex ratio of females to males was 2.2:1, with females attaining a significantly larger size than males. Gametogenesis followed a pattern similar to that of other freshwater teleosts peaking over the spawning period. Stomach content analysis and observations on feeding morphology revealed that A. natalensis was an opportunistic predator with large fish consuming larger prey from a greater variety of taxonomic groups. The most abundant prey items eaten were dipteran (particularly Chironomidae) and ephemeropteran (particularly Baetidae) larvae.  相似文献   

2.
A study on some biological parameters of the mountain catfish, Amphilius uranoscopus Pfeffer 1889 (Silurifomes: Amphiliidae), was carried out in the Thego stream on the slopes of Mount Kenya from February to December 2002. Physical and chemical profiles of the Thego show that the water quality parameters is typical of high altitude streams with temperatures rarely exceeding 18°C, DO ranging from 7.9 to 8.2 mg l?1 and relatively high conductivity (97–137 μS cm?1) typical of perturbed lotic environments. A total of 1010 fish were caught by an electro‐fisher, with sizes ranging between 8 and 24 cm fork length. The population structure had a unimodal distribution with maxima at 14–16 cm. The length–weight relationship showed relatively narrow range in the slope ranging from 2.61 in April to 2.98 in February 2002, thereby suggesting isometric growth pattern. The fitted growth pattern of A. uranoscopus showed an asymptotic length (L) of 28.5 cm and a growth curvature (K) of 0.56 year?1 resulting in an estimated natural mortality coefficient (M) of 0.90 year?1. The Fulton’s condition factor (K) was also relatively stable with a peak in April (0.92 ± 0.21) and lowest value in June (0.86 ± 0.10). As A. uranoscopus is not under commercial exploitation, the seemingly depressed population is possibly attributed to the introduced exotic rainbow trout that heavily predates on the species and environmental perturbations arising from changes in land use. The implications of such changes on A. uranoscopus are discussed.  相似文献   

3.
In Australia's arid and semi‐arid zone, most aquatic habitats are nonpermanent. Although approximately 70% of its land surface belongs to these zones, very little is known of the iconic ‘large branchiopods’ that inhabit these important and widespread habitats. In the present study, we investigated 737 Australian specimens of the spinicaudatan taxa Caenestheria and Caenestheriella with a combination of one mitochondrial (cytochrome oxidase subunit I; COI) and three nuclear (elongation factor 1α, internal transcribed spacer 2, and 28S) markers to assess the diversity of species, their phylogenetic relationships, and phylogeographical history. The initial species delimitation was based on COI employing a combination of phylogenetic analyses and two automated approaches to species delimitation (general mixed Yule coalescent model and Automated Barcode Gap Discovery). The outcome was tested by the nuclear markers and considered under differing species concepts. The number of delineated species ranged from 14–27, in no case being in full agreement with any of the two automated approaches. The lower numbers resulted if inferred reproductive isolation, as required for the biological or Hennigian species concept, was employed. Although nuclear markers did not indicate ongoing reproduction, the lack of sympatric co‐occurrences inhibited inferences of definitive reproductive isolation in several instances. If monophyly or an ‘independent evolutionary fate’ was employed, as required for the phylogenetic or evolutionary species concepts, the species' distribution was of no importance and up to 27 species could be delimitated. Because the Australian representatives of both studied genera could not be clearly separated from each other but constitute a single monophyletic clade separated from all available non‐Australian representatives of these genera, we describe a new spinicaudatan genus Ozestheria gen. nov. to accommodate these species. Populations revealed relatively small levels of genetic differentiation over large areas of central and eastern Australia. By far the most pronounced levels of genetic differentiation were observed towards the north‐eastern regions, a pattern possibly explainable by ecological conditions and the movement of nomadic water birds that disperse resting eggs. © 2015 The Linnean Society of London  相似文献   

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5.
Strophidon McClelland is a muraenid genus with characteristic appearance of a very elongated body, a large mouth cleft and anteriorly placed eyes. The nomenclature and taxonomic history of species within Strophidon are contentious and its members are easily misidentified. In the present study, species of the genus Strophidon are revised based on morphological and molecular data, and five species are considered valid, including S. dawydoffi Prokofiev, S. dorsalis (Seale), S. sathete (Hamilton), S. ui Tanaka and a new species, S. tetraporus. Strophidon tetraporus sp. nov. is described based on 15 specimens from Indonesia, the Philippines, Taiwan and Vietnam with the unique characteristic of the constant presence of the fourth infraorbital pore among species of Strophidon. The intraspecific variation of vertebral formula within S. dorsalis is discussed based on molecular data. Muraena macrurus Bleeker and Thyrsoidea longissima Kaup are synonyms of S. sathete that can be distinguished from the most similar congener S. ui by a longer tail, smaller eyes and more inner maxillary and inner dentary teeth. A key to identify species of Strophidon is provided. The distribution and maximum size of each species are also re-evaluated.  相似文献   

6.
The rapids-dwelling suckermouth catfish genus Pseudolithoxus was previously only known from the Guiana-Shield-draining Orinoco and Casiquiare river systems of Colombia and Venezuela, but new records have expanded this range considerably further into the Amazon basin of Brazil, and include occurrences from rivers draining the northern Brazilian Shield. These highly disjunct records are now placed in an evolutionary and phylogeographic context using a dated species tree constructed from mitochondrial (Cytb) and nuclear (RAG1) gene sequence data. Due to mito-nuclear discordance, we also delimit the putative species using statistical coalescent models and a range of additional metrics. We infer that at least two species of Pseudolithoxus are present in the Amazon basin: P. nicoi, previously only recorded from the río Casiquiare, but now also reported from the upper rio Negro, and a new species, which we describe herein from south-draining Guiana Shield and north-draining Brazilian Shield. Our data reject a simple model of Miocene vicariance in the group following uplift of the Uaupés Arch separating the Orinoco and Amazon systems, and instead suggest more complex dispersal scenarios through palaeo-connections in the Pliocene and also via the contemporary rio Negro and rio Madeira in the late Pleistocene.

www.zoobank.org/urn:lsid:zoobank.org:pub:46A6BEC1-1A1B-4244-80-A6-FD9CF8DA0384.  相似文献   


7.
Recent investigations in the upper Río Huallaga in Peru revealed the presence of an intriguing species of the Loricariinae. To characterize and place this species within the evolutionary tree of the subfamily, a molecular phylogeny of this group was inferred based on the 12S and 16S mitochondrial genes and the nuclear gene F-reticulon4. The phylogeny indicated that this distinctive species was a member of the subtribe Loricariina. Given its phylogenetic placement, and its unusual morphology, this species is described as a new genus and new species of Loricariinae: Fonchiiloricaria nanodon. This new taxon is diagnosed by usually possessing one to three premaxillary teeth that are greatly reduced; lips with globular papillae on the surface; the distal margin of lower lip bearing short, triangular filaments; the premaxilla greatly reduced; the abdomen completely covered by plates, with the plates between lateral abdominal plates small and rhombic; a caudal fin with 14 rays; the orbital notch absent; five lateral series of plates; dorsal-fin spinelet absent; preanal plate present, large and solid, and of irregular, polygonal shape, the caudal peduncle becoming more compressed posteriorly for the last seven to 10 plates.  相似文献   

8.
The delineation of Gammarus species is controversial because of extensive intraspecific morphological variation. The current study examined DNA sequences from the mitochondrial cytochrome c oxidase subunit I and the nuclear 28S genes as well as morphological and ecological data to determine the species boundaries of Gammarus species from China. The results of molecular analyses showed that Gammarus sp1, G. sp2, G. sp3, and G. sp4 are monophyletic and deeply divergent from sister groups. Detailed morphological and ecological comparisons with closely related species were consistent with molecular analyses. Gammarus sp1, G. sp2, G. sp3, and G. sp4 were described as four new species: Gammarus illustris sp. nov. , Gammarus clarus sp. nov. , Gammarus hypolithicus sp. nov. , and Gammarus parvioculus sp. nov. We recommend that molecular detected species should be formally named and described for future research. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 215–253.  相似文献   

9.
We review the systematics of the Hypsiboas calcaratus species complex, a group of widely distributed Amazonian hylid frogs. A comprehensive analysis of genetic, morphological, and bioacoustic datasets uncovered the existence of eleven candidate species, six of which are confirmed. Two of them correspond to Hypsiboas fasciatus and Hypsiboas calcaratus and the remaining four are new species that we describe here. Hypsiboas fasciatus sensu stricto has a geographic range restricted to the eastern Andean foothills of southern Ecuador while Hypsiboas calcaratus sensu stricto has a wide distribution in the Amazon basin. Hypsiboas almendarizae sp. n. occurs at elevations between 500 and 1950 m in central and northern Ecuador; the other new species (H. maculateralis sp. n., H. alfaroi sp. n., and H. tetete sp. n.) occur at elevations below 500 m in Amazonian Ecuador and Peru. The new species differ from H. calcaratus and H. fasciatus in morphology, advertisement calls, and mitochondrial and nuclear DNA sequences. Five candidate species from the Guianan region, Peru, and Bolivia are left as unconfirmed. Examination of the type material of Hyla steinbachi, from Bolivia, shows that it is not conspecific with H. fasciatus and thus is removed from its synonymy.  相似文献   

10.
This study re‐examined the taxonomic status of the sisorid catfishes usually identified as Glyptothorax zanaensis using a combination of morphometric and molecular data. Our results resurrect Glyptothorax longinema from the synonymy of G. zanaensis, and we describe two previously unnamed species as Glyptothorax granosus sp. nov. and Glyptothorax fucatus sp. nov. All four species are diagnosed and described in detail. Truss‐based morphometrics combined with principal component analysis (PCA) detected three principal components (PCs) that can explain 86% of the total variation amongst species, which mainly reflect the characteristics of body depth, related depth, adhesive apparatus length, pectoral‐fin length, caudal peduncle length, and barbel lengths. We also generated a phylogenetic hypothesis of these species using concatenated mitochondrial cytochrome b and d ‐loop gene sequences. Molecular dating analysis revealed a rapid speciation of Glyptothorax in the south‐eastern corner of the Qinghai‐Xizang Plateau from the middle Pliocene to early Pleistocene. A key to identify the Glyptothorax species from the Salween River drainage is also provided. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 363–389.  相似文献   

11.
Only a few species belonging to the Proseriata (Platyhelminthes) show a parenchymatic pigmentation, which may aid identification. Among these, Pseudomonocelis agilis has a yellowish body and is provided with a reddish–brown girdle in front of the statocyst. The species is known for limited areas of northern Europe and the Mediterranean. The present study was conducted to assess both the taxonomic status of populations attributed to the species across the unusually wide range for an interstitial flatworm, which lacks an obvious means of dispersal, and the levels of genetic variability within and among populations, by employing an integrative approach that included the analyses, on six populations, of three molecular markers (small subunit ribosomal 18S‐like gene, inter‐simple sequence repeat, allozymes), karyotypes, and 11 morphological characters. Furthermore, crossbreeding experiments were carried out on the Mediterranean populations. The results obtained revealed the existence of four highly divergent genotypic clusters, accompanied by karyological differences, with complete intersterility among the clusters tested. The combination of approaches adopted strongly supports the conclusion that the wide‐ranging European pigmented species P. agilis is actually composed of four species: P. agilis in the Baltic area; Pseudomonocelis cetinae in the Adriatic; and Pseudomonocelis sp. nov. A and Pseudomonocelis sp. nov. B in the western and eastern Mediterranean, respectively. The latter two species are morphologically indistinguishable for the parameters essayed. Reconstruction of the phylogenetic relationships of these taxa, including congeneric and consubfamilial outgroups, showed that pigmentation is a plesiomorphic condition for the genus Pseudomonocelis and that Pseudomonocelis sp. nov. A shares a previously undetected, sister‐group relationship with species of the unpigmented P. ophiocephala complex. The present study thus depicts complex speciation processes in a mesopsammic species, which involves allopatric divergence operating on different scales and ecological shifts, and highlights that the contribution of microturbellarians to marine biodiversity may be seriously underestimated. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 907–922.  相似文献   

12.
The chaetotaxy of 15 species of eastern North American Entomobrya is redescribed in order to determine potential characters for the diagnosis of cryptic lineages and evaluate the diagnostic and phylogenetic utility of chaetotaxy. As a result, four new species (Entomobrya citrensis Katz & Soto-Adames, sp. n., Entomobrya jubata Katz & Soto-Adames, sp. n., Entomobrya neotenica Katz & Soto-Adames, sp. n. and Entomobrya unifasciata Katz & Soto-Adames, sp. n.) are described, and new diagnoses are provided for Entomobrya assuta Folsom, Entomobrya atrocincta Schött, Entomobrya decemfasciata (Packard), Entomobrya ligata Folsom, Entomobrya multifasciata (Tullberg), and Entomobrya quadrilineata (Bueker). Furthermore, previously undocumented levels of intraspecific variation in macrosetal pattern are reported, tempering the exclusive use of chaetotaxy for species delimitation. Phylogenetic relationships, estimated using both morphological and molecular data, indicate that Entomobrya is likely paraphyletic. The phylogenies also suggest that unreliable character homology, likely fostered by Entomobrya’s profusion of macrosetae, may limit the phylogenetic utility of chaetotaxy in groups characterized by an abundance of dorsal macrosetae.  相似文献   

13.
Four loaches,Niwaella brevipinna Chen & Chen,sp.nov.,N.fimbriata Chen & Chen,sp.nov.,N.nigrolinea Chen & Chen,sp.nov.and N.qujiangensis Chen &Chen,sp.nov.,are described based on specimens collected from Zhejiang and Anhui Provinces,East China.The mitochondrial cytochrome b gene of 28 individuals of seven species from seven locations collected from Zhejiang,Anhui and Jiangxi Provinces were amplified and analyzed.Morphological and molecular data showed that N.fimbriata Chen & Chen,sp.nov.and N.nigrolinea Chen & Chen,sp.nov.,N.brevipinna Chen& Chen,sp.nov.and N.laterimaculata (Yan & Zheng),N.qujiangensis Chen & Chen,sp.nov.and N.longibarba Chen & Chen are closely related.The seven Chinese Niwaella species,N.brevipinna Chen & Chen,sp.nov.,N.fimbriata Chen & Chen,sp.nov.,N.laterimaculata,N.longibarba,N.nigrolinea Chen & Chen,sp.nov.,N.qujiangensis Chen & Chen,sp.nov.,and N.xinjiangensis are clearly distinguished by the combination of the color patter,mental lobes,suborbital spine,caudal peduncle,body shape,and subdorsal scales.  相似文献   

14.
South‐East Asia has an exceptionally high diversity of snakes, with more than 250 snake species currently recorded from Thailand. This diversity likely reflects the diverse range of geographical and climatic conditions under which they live, but the evolutionary history and population genetics of many snake species in South‐East Asia have been little investigated in comparison with morphological studies. Here, we investigated genetic variation in the monocled cobra, Naja kaouthia, Lesson, 1831, across its distribution range in Thailand using mitochondrial DNA (cytochrome b, control region) for ~100 individuals and the nuclear DNA gene (C‐mos) for a small subset. Using population genetic and phylogenetic methods, we show high levels of genetic variation between regional populations of this non‐spitting cobra, including the north‐eastern, north‐central and southern regions, in addition to a population on Pha‐ngan Island, 150 km offshore from the southern peninsula. Moreover, inclusion of the north‐eastern population renders N. kaouthia paraphyletic in relation to other regional Naja species. The north‐eastern population is therefore probably specifically distinct. Given that these cobras are otherwise undifferentiated based on colour and general appearance to the “typical” cobra type of this region, they would represent a cryptic species. As has been shown in other animal groups from Thailand, it is likely that the geographical characteristics and/or tectonic alteration of these regions have facilitated high levels of population divergence of N. kaouthia in this region. Our study highlights the need for dense sampling of snake populations to reveal their systematics, plan conservation and facilitate anti‐snake venom development.  相似文献   

15.
Summary  Taxonomy of the genus Echinodorus is partially revisited in the light of current understanding of the phylogenetic relationships of the genus. As a result of new taxonomy, the species status of some previously synonymised taxa are restored, other names are synonymised, and some nomenclatural problems unnoticed by previous authors are resolved. Two new species, Echinodorus reptilis and E. emersus are described. The subgeneric divisions of the genus are not accepted, and all subspecific taxa are either rejected or established as species. As a result, 28 species based on a phylogenetic species concept are now recognised in Echinodorus and an identification key to these species is provided.  相似文献   

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Previous studies have indicated the occurrence of nine species of Palaemon in Brazil. However, the extensive variability in their diagnostic characters and the geographic distribution of some species raises doubts about the validity of some taxa, potentially indicating the occurrence of species not yet reported from Brazil or even not described. To solve taxonomic issues with Palaemon species in Brazil, we carried out a multigene analysis by using partial fragments of 16S and COI mitochondrial genes and the nuclear H3. Phylogenetic relationships were inferred by maximum likelihood and Bayesian inference. The external morphology corresponding to the terminal clades obtained in the molecular phylogram was analysed to identify diagnostic characters that allow the recognition of the groups and the correct taxa assignment. The combined analysis of molecular and morphological data confirms the existence of nine species of Palaemon in Brazil, five from the “Palaemon” lineage (P. mercedae and four Palaemon stensu strictoP. argentinus, P. octaviae—first record in Brazil, P. northropi and P. paivai) and four of the “Alaocaris” lineage (P. carteri, P. ivonicus, P. pandaliformis and P. yuna). The possibility of further cryptic speciation is also pointed out. In addition to confirming the validity of the nine species, the results indicate the need for taxonomic adjustments and corresponding changes in the geographic distribution of Palaemon species occurring in Brazil.  相似文献   

19.
Of the silurid catfish genus Pterocryptis in Vietnam, a total of four species are recognized as valid, of which Pterocryptis crenula and P. verecunda are described here as new. The type locality of P. cochinchinensis is restricted to central Vietnam, and the species is redescribed from topotypic material. Pterocryptis crenula (from northeastern Vietnam) can be differentiated from its congeners in having visibly confluent anal and caudal fins while P. verecunda (from Cat Ba Island in northeastern Vietnam) can be differentiated from its congeners in having the genital papilla concealed behind the anus. Notes on the identity of other nominal Pterocryptis species are also provided.  相似文献   

20.
Temperate reefs, built by multilayers of encrusting algae accumulated during hundreds to thousands of years, represent one of the most important habitats of the Mediterranean Sea. These bioconstructions are known as “coralligenous” and their spatial complexity allows the formation of heterogeneous microhabitats offering opportunities for a large number of small cryptic species hardly ever considered.Although sponges are the dominant animal taxon in the coralligenous rims with both insinuating and perforating species, this group is until now poorly known. Aim of this work is to develop a reference baseline about the taxonomic knowledge of sponges and, considering their high level of phenotypic plasticity, evaluate the importance of coralligenous accretions as a pocket for biodiversity conservation.Collecting samples in four sites along the coast of the Ligurian Sea, we recorded 133 sponge taxa (115 of them identified at species level and 18 at genus level). One species, Eurypon gracilis is new for science; three species, Paratimea oxeata, Clathria (Microciona) haplotoxa and Eurypon denisae are new records for the Italian sponge fauna, eleven species are new findings for the Ligurian Sea. Moreover, seventeen species have not been recorded before from the coralligenous community. The obtained data, together with an extensive review of the existing literature, increase to 273 the number of sponge species associated with the coralligenous concretions and confirm that this habitat is an extraordinary reservoir of biodiversity still largely unexplored, not only taxonomically, but also as to peculiar adaptations and life histories.  相似文献   

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