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 15 毫秒
1.
The Volturno Spined Loach Cobitis zanandreai is thought to be restricted to only two places in Italy, the Fondi Lake (Latium) and the Volturno river basin (Campania). In this study we carried out a review of the available literature and surveyed 37 sites of potential occurrence. We discovered seven previously unknown populations of C. zanandreai in the Liri-Garigliano and the Pontine plain watersheds, significantly expanding the known limits of its distribution. We found the invasive C. bilineata only in the Amaseno River. Our results agree with records from the 19th and 20th centuries, highlighting the importance of historical data in understanding current species distribution. Our findings provided a substantial distribution update that allow to assess the species conservation status more objectively.  相似文献   

2.
Although the unique features of asexual reproduction and hybridization among European spined loaches (genus Cobitis ) have recently attracted the attention of conservation biologists, faunists and evolutionary biologists, the research has suffered from uncertain identification of specimens and their genomes because of the extreme morphological similarity of all the species within the hybrid complex. In this article, a Europe-wide study is reported, which was performed on samples collected by several research teams. Several complementary methodologies, such as allozyme analysis, karyotyping, flow cytometry and DNA sequencing allowed us to confirm or reject the existence of all previously reported species and their hybrids as well as to uncover several new hybrid biotypes. The biogeography of all the known biotypes, that is, parental species and hybrid biotypes, has been summarized here and the taxonomic position of two undescribed putative species mentioned in previous publications has been established. New polymerase chain reaction restriction fragment length polymorphism markers for species determination have further been developed and applied, which would allow the unambiguous identification of parental species and their genomes in the known hybrid biotypes within the complex.  相似文献   

3.
A phylogenetic analysis based on morphological characters indicates that Leptolebias Myers, 1952, a genus of small killifishes highly threatened with extinction, from Brazil, is paraphyletic. As a consequence, Leptolebias is restricted in this study to a well‐supported clade that includes Leptolebias marmoratus (Ladiges, 1934), Leptolebias splendens (Myers, 1942), Leptolebias opalescens (Myers, 1942), and Leptolebias citrinipinnis ( Costa, Lacerda & Tanizaki, 1988 ), from the coastal plains of Rio de Janeiro, and Leptolebias aureoguttatus ( Cruz, 1974 ) (herein redescribed, and for which a lectotype is designated) and Leptolebias itanhaensis sp. nov. , from the coastal plains of São Paulo and Paraná, in southern Brazil.Leptolebias is diagnosed by three synapomorphies: a caudal fin that is longer than deep, a single anterior supraorbital neuromast, and dark pigmentation that does not extend to the distal portion of the dorsal fin in males. A key is provided for the identification of species of Leptolebias. Three species formerly placed in Leptolebias, Leptolebias minimus (Myers, 1942), Leptolebias fractifasciatus ( Costa, 1988 ), and Leptolebias cruzi ( Costa, 1988 ), are transferred to Notholebias gen. nov. , which is hypothesized to be the sister group to the clade comprising Leptolebias, Campellolebias Vaz‐Ferreira & Sierra, 1974, and Cynopoecilus Regan, 1912. Notholebias gen nov. is diagnosed by two synapomorphies: a narrow basihyal and the presence of iridescent bars on the caudal fin in males; and three features interpreted as plesiomorphic, but not occurring in Leptolebias, Campellolebias, or Cynopoecilus, the presence of dermosphenotic, well‐developed contact organs on the pectoral fin in males, and an opercular region with red bars in males. ‘Leptolebiasleitaoi, a species from Bahia, in north‐eastern Brazil, is considered as having an uncertain phylogenetic position, as all known preserved material is presently lost, and the species may be extinct. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 147–160.  相似文献   

4.
In recent years, the biodiversity of freshwater fishes has been markedly decreasing worldwide because of anthropogenic activities. The Japanese striped loach, Cobitis kaibarai (Cypriniformes: Cobitidae), is a primary freshwater fish endemic to northern Kyushu, Japan. This species is designated as endangered IB class in the Red List by the Japan Ministry of the Environment. Its population is decreasing, possibly because of habitat loss and degradation. To conserve C. kaibarai populations, information on its basic ecology is necessary; nonetheless, its detailed life history and reproductive ecology have yet to be clarified. In this study, the authors conducted monthly capture–mark–recapture surveys and periodical observations to investigate the life history, spawning sites and season of C. kaibarai. They also evaluated the influence of creek reshaping (concrete revetment) on the C. kaibarai population in Saga Plain, northern Kyushu. Between 2015 and 2018, more individuals were captured during winter than summer. The average body width of females peaked in early June and small immatures were confirmed from July. Some individuals were captured across 15 or more months after their initial marking. In the survey of reproductive sites, eggs and larvae of C. kaibarai were found in shallow areas in mid-June; these were temporarily submerged following the increase in water level from early June. Therefore, C. kaibarai spawns in shallow areas during this season. Based on the capture–mark–recapture surveys, the estimated population density of C. kaibarai significantly decreased in a census site that had undergone creek reshaping, which contrasted with the results in a control site, where no significant difference was detected. The standard length of C. kaibarai increased following creek reshaping, suggesting that the proportion of C. kaibarai postponing spawning had increased, possibly because of degradation of spawning environments. The results of this study provide important ecological knowledge for the conservation of C. kaibarai and emphasize the importance of shallow waters for floodplain spawners.  相似文献   

5.
Enzymes, representing 23 genetic loci, were studied in n = 320 European river barbels (Barbus barbus L. 1758) from the contact zone of the Rhine and the upper Danube. Barbel revealed the highest heterozygosity estimate (He = 0.137) of 10 sympatric freshwater fishes (range He = 0.017–0.106). The geographical genetic subdivision in barbel (GST = 0.1690) surpassed the respective estimates in two other cyprinid species (GST ≤ 0.1415) and in three anadromous fishes (range GST = 0.0330–0.1290) from the same study area, but it fell short of the spatial genetic fragmentation of two resident salmonid species (GST ≥ 0.2678) and of sculpins (GST = 0.8489). The theoretical gene flow in the unobstructed Danube was NemDAN = 4.98, and across the weirs in the southern Rhine NemRHE = 1.84. The Rhine/Danube watershed exceeded any other isolation effect on the gene pool despite a low genetic distance (DRHE/DAN = 0.0321) among Rhenish and Danubian samples. The range history in central Europe might imply the colonization of the study area from a Danubian and from a Rhenish or a Rhôdanian refuge. The concluded admixture of eastern and western barbels has produced a weakly pronounced cline of increasing allozymic affinity of Rhenish to Danubian barbels in the southern Rhine system. Oberschwaben has served as an important colonization pathway in the phylogeographical exchange between the Danube and west Europe. The influence of stocking for fisheries on the allozymes is not known precisely, but it appears to be of minor importance.  相似文献   

6.
We studied the population genetic structure of Cobitis vettonica, an endangered freshwater fish species endemic to the Iberian Peninsula, in order to propose a biogeographic model of the responses of species to the multiple changes that occurred in the Iberian hydrological system during the Quaternary period. We also deciphered the relationship of C. vettonica with its sister species C. paludica, particularly in sympatric areas, and provide genetic information for conservation purposes. To achieve this goal, we analyzed both mitochondrial and nuclear data (the cytochrome b and the nuclear recombination activating 1 genes) and a battery of single‐nucleotide polymorphisms (SNPs) of 248 individuals of C. vettonica or C. paludica from 38 localities, including some sympatric ones, covering the entire distribution area of C. vettonica. We highlight the important role played by the hydrogeomorphological processes and climatic changes that occurred in the Iberian Peninsula during the Quaternary on both the population structure of C. vettonica and its relationship with its sister species C. paludica. Our results support the genetic introgression of populations at the eastern limit of the distribution of C. vettonica. Furthermore, we postulate genetic introgression in sympatric areas. Finally, we propose the establishment or expansion of four Operational Conservation Units (OCUs) for C. vettonica, and highlight the threat faced by its populations due to the low level of genetic diversity detected for some of its populations and genetic introgression with C. paludica, which could eventually displace C. vettonica, resulting in a loss of diversity in this species.  相似文献   

7.
A total sample of 99 specimens of the vulnerable fish species Cobitis paludica(de Buen, 1930), was collected on a monthly basis from a tributary of the River Guadalquivir between September 1990 and September 1991. Female longevity was 1 year longer than that of males, the former reaching age-class 5+. The diet of C. paludicaconsisted mainly of Ostracoda and chironomid larvae, benthic prey of small size and occasionally other resources, such as Macrobiotid eggs spawned during winter. Detritus in gastrointestinal content was scarce, which differs from other populations. Back-calculations of length were performed from scale annuli measurements. The relationship between standard length and scale radius was different for males and females. Females were larger than males of the same age. Both back-calculated length and theoretical length, calculated by applying von Bertalanffy's model, were larger for females. The relationship between female standard length (SL) and fecundity (F) was log F= –7.465 + 5.5753 log SL.  相似文献   

8.
Morphometric and electrophoretic variation are analysed among Iberian and African populations of Cobitis (Cobitidae). Three discrete morphotypes are distinguished, showing a remarkable genetic differentiation among them. Each of the three morphotypes is judged to represent a species, one being described as a new species. Both approaches agree on the separate status of the Iberian populations from the Alagón drainage, Tagus basin of west central Spain. This population is described as a new species, Cobitis vettonica sp. nov., a sexually dimorphic spined loach was assigned to the subgenus Iberocobitis Bacescu, 1961. Morphometric and electrophoretic data placed this new species phenetically close to Cobitis maroccana Pellegrin, 1929 and Cobitis pahdica De Buen, 1930, but differs from these species in overall shape, male coloration pattern, shorter barbels and fins, posterior lamina of the cleithrum, seven branched rays on the dorsal fin and in having a unique alleles at sAAT-2*, EST-1* and MPI* loci. The new species range described in this paper is more restricted than that of C. pahdica. Both inhabit the Tagus basin but have not been reported to be sympatric.  相似文献   

9.
10.
11.
This paper investigates the distribution of species richness, rarity and endemicity of European land mammals (bats and introduced species excluded). The highest level of species richness was in Central Europe, while Southern areas had the highest rarity and endemicity scores. The distribution of richness was affected by the location of sampling points in islands and peninsulas. After excluding these sampling points, richness continued to decrease Westward suggesting the existence of a large-scale peninsular effect on mammal distribution. These patterns of continental distribution of richness, rarity and endemicity could be the result of the distribution of refuge areas in the southern Mediterranean peninsulas, and the Pleistocene advances and retreats of mammals throughout the Western Palearctic. Thus, European mammal distribution can be interpreted on the basis of two different patterns of abundance distribution in which Palearctic species reduce their abundance from central-Europe outwards, while endemic, rare species show a similar depletion in the North. It should be useful to evaluate the role of the different regions in Europe in conserving the demographic interactions between central and peripheral populations of mammal species. Given the restricted distribution and potential small size of population, these endemic species are most likely to be susceptible to anthropogenic environmental degradation.  相似文献   

12.
Morphologically similar populations of Aphanius that are currently considered as A. sophiae inhabit the endorheic Kor River Basin in the Zagros Mountains. Using genetic analysis based on mtDNA (cytochrome b), combined with examination of morphology (morphometry, meristics, otoliths), we discovered that what is thought to be A. sophiae is actually two distinct species, one of which is described as A. shirini sp. n. The males of the new species can be distinguished from those of all other Iranian inland Aphanius species by having only 7–10 clearly defined white flank bars, which is the lowest number of flank bars among the Iranian inland Aphanius species. Both males and females differ from all other Iranian inland Aphanius species by having a significantly longer caudal peduncle and a smaller dorsal fin depth. Based on the PhyML and Bayesian likelihood trees, A. shirini is sister to A. vladykovi from the Karoun Basin in the Zagros Mountains. Our results indicate that an ancient exorheic Kor River Basin existed in the Late Miocene and Pliocene. The close phylogenetic relationship between A. shirini and A. vladykovi suggests that the pre‐Pliocene drainage in the ancient Kor River Basin was directed to the north‐west (to the Karoun Basin), and not to the south‐east as in the present‐day Kor Basin. Both A. shirini and A. vladykovi represent the highest altitude records for Aphanius. We conclude that the splits of A. shirini and A. vladykovi can be linked to tectonic events in the Middle to Late Miocene, which created the highest altitudes (>3000 m) in the Zagros Mountains, and led to isolation of populations. The present‐day endorheic Kor Basin is known to have formed in the Late Pleistocene or Early Holocene, and the ‘young’ age of A. sophiae is clearly related to this history. Our results contribute to elucidate the link between geological history and the present‐day species diversity in the tectonically still active Zagros Mountains of Iran.  相似文献   

13.
This study is focused on a poorly known genus of small killifishes, Xenurolebias, comprising species uniquely living in temporary pools of the Atlantic Forest in the coastal plains of eastern Brazil (a region undergoing intense deforestation). Xenurolebias comprises two nominal, morphologically similar species, but some variability among populations suggests it represents a species complex. In order to delineate species limits, a taxonomic revision was conducted combining two different approaches: (i) a character-based approach using morphological variation (colour patterns, fin morphology, meristic and morphometric data) and (ii) a tree-based approach using mt-DNA (tRNA-Met, tRNA-Gln and ND2). The results strongly supported four species: X. myersi (Carvalho) from the Itaúnas river basin and adjacent smaller drainages; X. izecksohni (Cruz) from the Barra Seca river basin; X. cricarensis Costa, sp. nov., from the São Mateus river basin; and X. pataxo Costa, sp. nov., from the Mucuri, Itanhem and Jucuruçu river basins. Recognition of four distinct species in Xenurolebias should change views about the conservation of the species, one of which (X. pataxo) is seriously endangered and should be considered a priority for conservation.http://zoobank.org/urn:lsid:zoobank.org:pub:8485DD00-3F30-4C9F-9682-62C4718D53D9  相似文献   

14.
The Kahuzi-Biega National Park (KBNP), situated mainly in the Eastern Highlands Ecoregion of the Upper Congo basin, is drained by the Lowa and Ulindi rivers, and some western affluents of Lake Kivu. In this study, the first list of the fish diversity of these systems is provided based on museum collections and complemented, for the Lowa River system and the western Lake Kivu affluents, with recently collected specimens (2013–2017). A total of 118 species are reported from the Lowa basin, 22 from the Ulindi basin and seven from these Lake Kivu affluents. Within the Lowa and Ulindi, respectively, five and one species, all cichlids, have been introduced. Currently, 51 species are reported from within the park, only two of which have been reported from the highlands, i.e., Amphilius kivuensis from the Luha, the source of the Luka River, and Clarias liocephalus from the headwaters of the Lake Kivu’ affluents. With a total of 30 species, Cyprinidae is by far the largest family, representing 25% of the total species diversity of the Lowa basin. It is followed by Mormyridae with 13 species (11%), Alestidae and Mochokidae with 10 species each (8%), Clariidae and Amphiliidae with eight species (7%), and Distichodontidae with six species (5%). Seven new species for science were discovered and 11 species were found to be endemic to the Lowa system. Although further exploration is needed, this underscores the importance of the KBNP in protecting the fish fauna of the Lowa basin but also highlights the park's limited coverage of the fish fauna of the Lowa basin.  相似文献   

15.
Recent advances in population history reconstruction offered a powerful tool for comparisons of the abilities of sexual and clonal forms to respond to Quaternary climatic oscillations, ultimately leading to inferences about the advantages and disadvantages of a given mode of reproduction. We reconstructed the Quaternary historical biogeography of the sexual parental species and clonal hybrid lineages within the Europe-wide hybrid complex of Cobitis spiny loaches. Cobitis elongatoides and Cobitis taenia recolonizing Europe from separated refuges met in central Europe and the Pontic region giving rise to hybrid lineages during the Holocene. Cobitis elongatoides due to its long-term reproductive contact with the remaining parental species of the complex--C. tanaitica and C. spec.--gave rise to two clonal hybrid lineages probably during the last interglacial or even earlier, which survived the Würmian glaciation with C. elongatoides. These lineages followed C. elongatoides postglacial expansion and probably decreased its dispersal rate. Our data indicate the frequent origins of asexuality irrespective of the parental populations involved and the comparable dispersal potential of diploid and triploid lineages.  相似文献   

16.
Poyang Lake Basin is of great importance to maintain regional ecological balance. However, fish biodiversity in this basin has rapidly declined as the result of anthropogenic habitat alteration, such as dam construction, sand mining, and water pollution. Here, we aimed to analyze the temporal and spatial changes in biodiversity patterns of fish in Poyang Lake Basin over the last 37 years. The number of fish species underwent a significant decrease in the current period. In particular, 36.7% of the migration of fish was extirpated. Twenty‐seven fish species have been formally assessed using the Chinese Red List were currently listed as Critically Endangered (9), Endangered (3), Vulnerable (10), and Near Threatened (5). Alpha and gamma diversity revealed that fish diversity had also decreased, and beta diversity showed significant composition dissimilarity in two periods. PCoA showed that the historical fish composition dissimilarity was significantly different from that of the current period. We found a significant effect of the geographical distance on the spatial turnover component for the historical and current periods. In addition, the nestedness component was the main contributor to beta diversity, which indicated one large protected area should be established in Poyang Lake and the Ganjiang River Basin with higher species richness. These results indicated that fish biodiversity declined in the current period likely caused by anthropogenic habitat alteration and other threatened factors. Therefore, we suggest that the habitat reconstruction and biodiversity conservation for fish have become imperative in this basin, and a complete management plan should be carried out.  相似文献   

17.
The addition of species to the European butterfly list since 1983 has resulted in a number of highly significant changes. Most important are the increases in the number and proportion of endemics and of rare species, and a regional excess of species and endemics for southern Europe compared to northern Europe. There is also a surplus of Lycaenidae and Satyridae compared to other families, and an increase in species per genus associated with the reduction in genera. These additions raise two issues. First, the potential conservation load for European butterflies is inflated at species level. This is especially the case for southern Europe, which has disproportionate increases in rare and endemic species, more particularly if rarity and endemism are found to equate with threat of extinction. Second, the inflation in rarity and endemism suggests that there is a trend to promote ever more local populations (races, subspecies) to species. The taxonomic status of species being added to the list, a quarter of which are regarded as doubtful, is increasingly difficult to determine. Consequently, there is a danger that this may call into question the validity and objectivity of taxonomic practices, and of databases dependent on them, used by conservation. Revision of higher and lower butterfly taxa is urgently required.  相似文献   

18.
湖北新记录属植物永瓣藤种群现状及其保护   总被引:1,自引:0,他引:1  
永瓣藤(MonimopetalumchinenseRehd.)为湖北省种子植物区系新记录属、种,是中国二级保护植物。通山县分布的永瓣藤为次生杉、竹、阔混交林内的伴生成分,群落生活型谱以常绿高位芽植物为主,种群空间分布格局为集群型。其生态适应为明显的偏酸性和一定的耐荫性。永瓣藤种群虽规模小,但具明显的增长型特征,有发展潜力。文中对永瓣藤生物多样性保护提出了具体的建议  相似文献   

19.
根据东北地区生物多样性特征,利用系统保护规划方法和国际上常用的保护规划软件C- plan,计算了规划单元的不可替代性值,确定了区域生物多样性热点地区,并根据保护区分布现状进行了生物多样性保护空缺分析.结果显示,东北地区不可替代性较高的热点地区有4个,分别是:(1)长白山西北部林区,(2)大兴安岭北段山地区,(3)大兴安岭南部森林与草原过渡区,(4)松嫩平原中部湿地区. 在优先、一般、非优先3个等级中,需要优先保护地区的总面积是19.49×104km2,约占区域总面积的20.91%.同时,根据已建保护区分布情况研究发现,区域内存在3个明显的保护空缺,即长白山西北部林区、大兴安岭北段山地区和大兴安岭南段森林草原过渡区.建议新建和扩建保护区,同时建立生态廊道把相应的保护区关联起来,以实现区域内生物多样性保护目标.  相似文献   

20.
Taxonomy of the live‐bearing fish of the genus Ilyodon Eigenmann, 1907 (Goodeidae), in Mexico, is controversial, with morphology and mitochondrial genetic analyses in disagreement about the number of valid species. The present study accumulated a comprehensive DNA sequences dataset of 98 individuals of all Ilyodon species and mitochondrial and nuclear loci to reconstruct the evolutionary history of the genus. Phylogenetic inference produced five clades, one with two sub‐clades, and one clade including three recognized species. Genetic distances in mitochondrial genes (cytb: 0.5%–2.1%; coxI: 0.5%–1.1% and d‐loop: 2.3%–10.2%) were relatively high among main clades, while, as expected, nuclear genes showed low variation (0.0%–0.2%), with geographic concordance and few shared haplotypes among river basins. High genetic structure was observed among clades and within basins. Our genetic analyses, applying the priority principle, suggest the recognition only of Ilyodon whitei and Ilyodon furcidens, with I. cortesae relegated to an invalid species, the populations of which belong to I. whitei.  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