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1.
The mitochondrial cytochrome b gene was sequenced for six individuals of the pygmy madtom, Noturus stanauli, a globally imperilled catfish, from both known localities in Tennessee (U.S.A.) separated by over 1055 river km. Phylogenetic and population genetic analyses revealed little divergence between these populations for this locus.  相似文献   

2.
Abstract The bionomics of Campoletis chlorideae and the regularity of its seasonal fluctuations were studied in Changsha district, Hunan province. Field investigation indicated that there were ten generations of C. chlorideae a year, of which seven occurred in cotton fields. Three peaks of cotton bollworm parasitization by C. chlorideae were observed, early May to late June, mid August to early September, mid September to mid October respectively. One peak occurred in tomato and tobacco fields, the other two in cotton fields. The parasitization rate ranged from 25. 1 % ‐63. 1 %. The total development time from egg to adult ranged from 13. O days at 32°C to 75. 5 days at 11. 6 °C. Each wasp could parasitize the 5–23 second instar larvae of tobacco caterpillar. C. chlorideae could parasitize the cotton bollworm, beet armyworm and tobacco caterpillar, but preferred the cotton bollworm larvae. C. chlorideae could parasitized 1st‐ 3rd instar larvae of the tobacco caterpillar, but seldom parasitzed 4th ‐ 6th instar larvae. Moreover, C. chlorideae preferred second instar larvae. Theoretical models for developmental speed, adult longevity and the influence of temperature were proposed. The overwintering of C. chlorideae Uchida was also discussed. Moreover, methods for utilization of C. chlorideae Uchida in crop protection were presented and the bionomics of Curyoletis chlorideae in both the Yangtze River Valley and Yellow River Valley were compared.  相似文献   

3.
We investigated the recent evolutionary history of the Danube crested newt, Triturus dobrogicus through reconstructions of: (1) the number and position of refugia at the last glacial maximum, (2) the role of major central European rivers in pattern of post‐glacial dispersal, and (3) the present‐day distribution pattern. We analysed sequences of mitochondrial DNA (ND2, 1065 bp) and six microsatellite loci in 363 T. dobrogicus individuals from 58 populations covering the range of the species. Our analyses suggested that T. dobrogicus survived the last glacial maximum in two separate refugia positioned in northwestern Pannonia and in Southern Pannonia from where its range expanded along the Danube and Tisza Rivers. Our findings also confirmed that rivers played an important role in shaping the evolutionary history of amphibian species in Central Europe. We compared the T. dobrogicus range with another lowland amphibian, the fire‐bellied toad Bombina bombina, using species distribution modelling. In line with these models, the isolated mountains inside Pannonia are occupied not by B. bombina, but by its mountain‐dwelling sister‐species B. variegata. However, in contrast to the model, crested newts (including T. dobrogicus) are absent from these mountains. We attribute this biogeographical discrepancy to the positioning of the species’ refugia at the last glacial maximum.  相似文献   

4.
A new minnow species, Enteromius thespesios, is described from the south-eastern part of the upper Congo River; that is, the Kalule Nord, the Luvilombo and the Chambeshi Rivers. Enteromius thespesios belongs to the group of the soft-rayed species of Enteromius from the Congo Basin; that is, those with a weakly ossified, flexible last unbranched dorsal-fin ray that lacks serrations along its posterior edge. Within this group, E. thespesios is most similar to E. humeralis, from which it is distinguished by a higher number of circumpeduncular scales and shorter anterior and posterior barbels. Enteromius thespesios is a rheophilic and territorial species. It exhibits a marked sexual dimorphism, with males having: a red band towards the distal edge of dorsal, caudal and, to a lesser degree, anal fin; nuptial tubercles; a longer snout; longer pectoral fins; a shorter anal fin. This study gives extensive consideration to sexual shape differences for a species of Enteromius and also briefly reviews the current knowledge of sexual dimorphism in the species of Enteromius from the Congo Basin. Some conservation issues related to the new species are also highlighted.  相似文献   

5.
Morphological examination of Potamoglanis specimens from three localities in the Essequibo River basin, Guyana, and one location in the Branco River basin, Brazil, confirmed their identification as Potamoglanis wapixana – a species originally described from only the Branco River basin. Morphological similarity of these miniature catfishes on opposite sides of the Rupununi savannah watershed divide and new records from lentic habitat suggest that either their modern populations predate the Pliocene division of the Branco and Essequibo rivers or the species is capable of living in and/or migrating across the Rupununi Portal – a seasonally flooded hydrological connection known to facilitate the movement of mostly much larger fishes between the Branco and Essequibo basins.  相似文献   

6.
Summary

During 1973/74, Barbus poechii, Oreochromis macrochir, O. andersonii, Serranochromis angusticeps, S. codringtonii, S. robustus and S. thumbergi from the Okavango System were introduced into the Shashe Dam (Limpopo System, Botswana). These species are alien to the Limpopo System. A fish survey during September 1991 disclosed the presence of two specimens of the greenhead tilapia O. macrochir in a large natural pool in the Limpopo River 7 tan downstream from the Shashe/Limpopo confluence. In August 1992 another specimen was caught in this pool. It is surmised that the likely origin of these specimens is the Shashe Dam. There is a possibility that the greenhead tilapia may interbreed with the indigenous Mocambique tilapia O. mossambicus. Consequently the genetic integrity of O. mossambicus in the Limpopo River may become suspect. If the other alien species introduced into the Shashe Dam reach the Limpopo River, O. andersonii may also interbreed with O. mossambicus while the Serranochromis spp. could be detrimental for feeding relationships in the Limpopo River and its tributaries. The impact that B. poechii could have is uncertain but it does not appear to co-exist with the closely related B. trimaculatus of the Limpopo System. Eradication of O. macrochir in the Limpopo River is not practical. Further stocking of the Shashe Dam as well as other impoundments in the Limpopo System with alien fish species should be discouraged.  相似文献   

7.
This study investigated the morphology, morphometric and meristic characters of 117 larval Pimelodus britskii showing early development of head, eye, barbel and snout. Body and mouth pigmentation increased throughout development; the mouth was ventrally situated in the yolk-sac stage, becoming subterminal afterwards, and an embryonic fin was visible in all four stages observed. Post-flexion larval P. bristskii are distinguished from larval P. ortmanni by having 47–50 myomeres (v. 36).  相似文献   

8.
Feeding habits of Acetes paraguayensis (Hansen) were studied by examining the stomach content of specimens from two lakes. A. paraguayensis is omnivorous, feeding mainly on members of littoral-benthic and lotic communities. Algae, rotifers and microcrustaceans (copepods and cladocerans) are the more frequent items in the bulk of the stomach content. Oligochaeta and Diptera larvae were an alternative food source when available. Shrimp feeding habits difference between the two lakes may be due to the resource availability. A. paraguayensis are trophic linkers between limnetic and lotic habitats with an important role in the transportation of energy from the floodplain to the principal channel in the Paraná Rivers System.  相似文献   

9.
Two new species of Characidium, C. tatama and C. dule, are described from the biogeographic Chocó region in western Colombia. Both new species are supported by both morphological and molecular data. C. tatama from the San Juan River in the Pacific and C. dule from the Atrato River in the Caribbean portion of Colombia are both distributed in the upper and lower portions of these basins. An extensive comparison with other trans- and cis-Andean species of Characidium was made, in addition to species delimitation, using COI sequences by distinct methods (GMYC, ABGD, bPTP).  相似文献   

10.
As part of an ongoing taxonomic revision of the genus Heptapterus from the Laguna dos Patos and Uruguay River drainages and Atlantic coastal streams of southern Brazil and Uruguay, two new species closely related to Heptapterus mustelinus were identified. Both species are endemic to small tributaries of the Uruguay River. The two new species are distinguished from each other and from other species of Heptapterus by arrangement of cephalic and trunk laterosensory systems, number of vertebrae and number of dorsal, pectoral and anal-fin rays. Phylogenetic analyses of mitochondrial DNA (coI and cytb) sequence data further supports distinctiveness of the two new species.  相似文献   

11.
The present study employed basic and molecular cytogenetic methods to characterize three populations of Parauchenipterus galeatus from the basins of the Paraná and São Francisco Rivers, and a region of connection between the two basins. Although the diploid number was equal to 58 chromosomes, variations in karyotype formula were detected among the populations. B chromosomes were detected only in the population from the São Francisco River. Heterochromatin was located in the terminal position in almost all the chromosomes and in the pericentromeric position in some acrocentric chromosomes in the three populations. A single nucleolus organizer region was detected by silver nitrate and 18S rDNA‐fluorescent in situ hybridization in the short arm of one subtelocentric pair in the three populations, varying only in the chromosome pair bearing this site. The 5S rDNA sites were located in two submetacentric chromosome pairs in the three populations, varying only in the chromosome pairs bearing these sequences. Classic and molecular chromosome markers, along with the context of the natural history of the formation of hydrographic basins, ecological aspects, and the geographic isolation of populations between hydrographic basins and within the same basin, were important contributions to the discussion on possible biogeographic relations among the populations of Parauchenipterus galeatus. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 648–656.  相似文献   

12.
Aim This study aims to elucidate the phylogeography of the murid rodent Lemniscomys striatus and to evaluate the relative roles of ecological change, habitat patchiness, rivers and geological barriers in structuring patterns of diversity. Location Sub‐Saharan Africa. Methods The extent of phylogeographic patterns and molecular genetic diversity (cytochrome b gene) were addressed in a survey of 128 individuals of L. striatus from 42 localities. Using maximum parsimony, maximum likelihood, Bayesian, network and genetic structure analyses, we inferred intraspecific relationships and tested hypotheses for historical patterns of gene flow within L. striatus. Results Our results identified four major geographical clades within L. striatus: a West African clade, a Benin‐Nigeria clade, a Central African clade, and an East African clade. Several subclades were identified within these four major clades. Restricted gene flow with isolation by distance was recorded, which is congruent with the low dispersal ability of such a small murid rodent. No clear signal of population expansion was detected within clades or subclades. Main conclusions The western rift system and the Volta and Niger rivers may have acted as long‐term extrinsic barriers to gene flow, resulting in the emergence of the four main clades of L. striatus. The observed pattern of mitochondrial variation observed within each clade probably results from late Pleistocene climatic and vegetation changes: during adverse conditions (forest expansion), L. striatus may have survived only in refugia, and then experienced range expansion under favourable conditions (savanna expansion).  相似文献   

13.
Fish scales are morphologically diverse among species, within species, and even among individuals. The present study investigated macro- and micromorphology of the scales between two closely related Aphanius species in southern Iran including Aphanius hormuzensis, collected from Gotab/Mehran River and A. stoliczkanus, from Howba hot sulphuric spring. The results indicated clear interspecific differences in scale macromorphology and microstructures. The scales of A. hormuzensis are characterised by a rounded shape, 7–9 (mean 8.0±0.83) primary radii, and a relatively large focus with oblong shape that positioned centrally on the scale, while the scales of A. stoliczkanus are characterised by a polygonal shape with few spines in posterior region, 8–11 (mean 10.0±0.78) primary radii and a small rounded focus that positioned posterocentraly on the scale. These species are morphologically close but clearly distinguished by their scale morphology and habitat requirements (e.g. water depth and food availability). Therefore, it can be assumed that clear differences in their scale morphology have been resulted by the combination of both genetic and environmental factors.  相似文献   

14.
Thesystematics of the genus Gobio, especially of the populations on the southern Black Sea coast, seems to be still far from being resolved. Seven species were rec-orded from the northern Black Sea coast while three species were recognized from the southern Black Sea coast. We examined in total 43 specimens from K?z?l?rmak River (southern Black Sea basin), 80 specimens from Çoruh River (the Western Cau-casus of the Black Sea basin), 14 specimens from Rioni River (the Western Caucasus of the Black Sea basin), and 6 specimens from Kherota and Shakhe Rivers (the Western Caucasus of the Black Sea basin). Based on an analysis of 32 metric and 5 meristic data as well as the number of vertebrae, we concluded that the K?z?l?rmak and Coruh populations are two distinct, unnamed species, and we describe them here as Gobio kizilirmakensis from the K?z?l?rmak River and G. artvinicus from the Çoruh River.

http://www.zoobank.org/urn:urn:lsid:zoobank.org:pub:1ED54FB1-588F-4412-B376-4BE4E4516EB1  相似文献   

15.
Fluviopupa kessneri n. sp. is described from the Mulgrave River and one of its major tributaries, the Little Mulgrave River, in north-east Queensland. It is the first record of the Fluviopupa group from a continental area, other members of the genus being known only from Fiji, New Guinea and a few other Pacific Islands, including New Caledonia.  相似文献   

16.
Bellamya aeruginosa is a widely distributed Chinese freshwater snail that is heavily harvested, and its natural habitats are under severe threat due to fragmentation and loss. We were interested whether the large geographic distances between populations and habitat fragmentation have led to population differentiation and reduced genetic diversity in the species. To estimate the genetic diversity and population structure of B. aeruginosa, 277 individuals from 12 populations throughout its distribution range across China were sampled: two populations were sampled from the Yellow River system, eight populations from the Yangtze River system, and two populations from isolated plateau lakes. We used seven microsatellite loci and mitochondrial cytochrome oxidase I sequences to estimate population genetic parameters and test for demographic fluctuations. Our results showed that (1) the genetic diversity of B. aeruginosa was high for both markers in most of the studied populations and effective population sizes appear to be large, (2) only very low and mostly nonsignificant levels of genetic differentiation existed among the 12 populations, gene flow was generally high, and (3) relatively weak geographic structure was detected despite large geographic distances between populations. Further, no isolation by linear or stream distance was found among populations within the Yangtze River system and no signs of population bottlenecks were detected. Gene flow occurred even between far distant populations, possibly as a result of passive dispersal during flooding events, zoochoric dispersal, and/or anthropogenic translocations explaining the lack of stronger differentiation across large geographic distances. The high genetic diversity of B. aeruginosa and the weak population differentiation are likely the results of strong gene flow facilitated by passive dispersal and large population sizes suggesting that the species currently is not of conservation concern.  相似文献   

17.
Stuart  Ivor G.  McKillup  Stephen C. 《Hydrobiologia》2002,479(1-3):231-236
The relationship between the number of rings present in sagittal otoliths and the age of barramundi, Lates calcarifer (Bloch, 1790) [Centropomidae], was investigated by examining cross sectioned otoliths of 37 tagged fish of known age between 1 and 5 years from the Johnstone River, north Queensland. Concentric rings were clearly visible in all otolith sections and were validated as annual marks. The technique was then used to estimate the age and calculate von Bertalanffy growth parameters for 70 barramundi from the Fitzroy River, central Queensland. Growth appeared to be rapid but variable in the first year; the von Bertalanffy growth parameters for length versus age were L =690 mm, K=0.53, t 0= 0.003 years. October 1 was designated as the birth date. Whole otolith length, width and thickness were also approximated well by the von Bertalanffy equation. We suggest that examination of otoliths is a useful technique for ageing barramundi but note that further validation of the ageing method is still needed for fish older than six years.  相似文献   

18.
Since Margaritifera marocana (Pallary, 1918) and M. laosensis (Lea, 1863) were rediscovered, M. homsensis (Lea, 1865) remains the only pearl mussel species known solely based on old shell samples from natural history museums. This is also the last pearl mussel species, which is absent in a phylogeny of the family. Here, we aimed to provide an integrative revision of the taxonomic status of M. homsensis from the Orontes Basin. Using a newly collected specimen from the River Karasu, Hatay Province, southern Turkey, five gene partitions were sequenced, the cytochrome c oxidase subunit I (COI), large ribosomal subunit rRNA (16S), large ribosomal subunit rDNA (28S) and its D3 expansion segment (D3), and small ribosomal subunit rDNA (18S). The multi-gene phylogeny indicates that M. homsensis is a sister taxon of M. auricularia, but both these species are closely related to M. marocana by nuclear genes. The main conchological features, i.e., the shell shape, teeth morphology, and mantle attachment scars, as well as Fourier shell shape analysis have not shown principal differences between M. homsensis and M. auricularia. Based on these data, we concluded that M. homsensis is a valid species that is most closely related to M. auricularia. Special conservation efforts for a population of M. homsensis discovered in Turkey, including the formation of a nature reserve, might contribute to the conservation of the species. Finally, an extensive search for surviving populations in Orontes drainage (southern Turkey, Lebanon, and Syria) and the Nahr-el-Kabir River (Lebanon and Syria) remains necessary to develop a transboundary conservation strategy for this unique taxon.  相似文献   

19.
A new cave‐dwelling fish species Triplophysa guizhouensis is described based on specimens collected from Guizhou, China, in a subterranean system interconnected with the Hongshui River drainage. The species can be distinguished from its congeners by a combination of characters: eyes present; caudal fin with 14 branched rays; inner gill rakers of first gill arch 8–10; posterior chamber of air bladder developed; and body posterior of dorsal fin scaled. A key to species of Triplophysa in the Pearl River basin is provided.  相似文献   

20.
We assess variation in morphological and molecular characters among three species of Myosorex (the mouse shrew) –Myosorex geata, Myosorex kihaulei, and Myosorex zinki– as a means to test previously proposed biogeographic hypotheses for Tanzanian ‘sky islands’ and systematic hypotheses for Tanzanian mouse shrews. We analyse 17 cranial and dental variables using multivariate statistics and perform phylogenetic and phylogeographic analyses on sequences of mitochondrial and nuclear DNA; samples are drawn from every known Tanzanian population of Myosorex. Morphometric and phylogenetic analyses reveal that M. zinki is distinct, but that currently isolated populations of M. geata and M. kihaulei are relatively similar to one another, and may not have been isolated over geological time scales. Analyses of molecular variance identify statistically significant, but limited, genetic variation within and between isolated populations of M. geata and M. kihaulei. Between two putative regional biogeographic boundaries, greater genetic variation is explained by grouping populations on either side of the Ruaha River than by grouping populations on either side of the Makambako Gap. Our results are in agreement with recent studies illustrating the close relationship between faunas of the Southern Highlands and southern Eastern Arc Mountains, diminishing the apparent importance of the Makambako Gap as a historical biogeographic barrier. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 669–680.  相似文献   

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