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 109 毫秒
1.
The spatial genetic structure of a species, and whether distinct genetic lineages are present, is strongly influenced by their biology and habitat requirements. Given habitat specificity and low vagility, many herpetofaunal species are reservoirs for high levels of cryptic diversity; chameleons are a case in hand. The common flap-necked chameleon Chamaeleo dilepis has a large range that spans much of sub-Saharan Africa. Within South Africa, the species is largely confined to the north-eastern and central areas of the country, and occurs from the coastal forests in southern KwaZulu-Natal westwards into Namibia. Their large range, together with anecdotal evidence that there is considerable morphological and phenotypic diversity across the range, suggests a questionable taxonomy with possible cryptic lineages. The aims of the present study were to investigate whether C. dilepis is genetically structured across parts of its South African range, and whether this species (as it currently stands) might include cryptic lineages. To this end, 72 C. dilepis individuals sampled from four localities across South Africa (Gauteng, n = 2; KwaZulu-Natal, n = 2) were sequenced for two mitochondrial markers (ND4 and 16S). The phylogenetic results suggest that C. dilepis is indeed spatially structured. In addition, the large sequence divergence values between groups strongly suggests the presence of cryptic lineages and, pending the inclusion of more data from a larger geographic range, the group may be in need of a taxonomic revision.  相似文献   

2.
3.
Parasitic infections can impact the fitness of individuals and can have influence on animals’ population dynamics. An individuals’ parasite prevalence often changes depending on external or seasonal changes, for example, rainfall and ambient temperatures, but also on internal changes, for example, changes in body condition. In this study we aimed to identify the environmental factors that may influence the intestinal parasite and ectoparasite prevalence of the folivorous Malagasy primate species, Lepilemur edwardsi, living in a seasonal dry deciduous forest. Species living in this habitat have to adapt to seasonal changes of ambient temperature, with almost no precipitation during the dry season and hence strong fluctuations of resource availability throughout the year. We sampled the feces and ectoparasites of L. edwardsi throughout the year. Intestinal parasite prevalence increased from the wet to the dry season and was highest in the late dry season, which might be due to the accompanying decrease in diet quality. Conversely, ectoparasite prevalence decreased in the dry season, presumably due to the prevailing unfavorable environmental conditions for the development of ectoparasites (i.e., mites and ticks). Paired with the higher resting metabolism and stress level of L. edwardsi during the late dry season, it seems that this species may struggle when dry seasons intensify in its habitat.  相似文献   

4.
Two recent studies have suggested that divergent mitochondrial lineages may be present within spirostreptid genera such as Bicoxidens Attems, 1928. Bicoxidens, similar to many other endemic soil invertebrates, exhibits low dispersal capabilities and strict microclimate habitat preferences, attributes that often lead to geographic isolation. Given that prolonged geographic isolation often lays the foundation for population genetic differentiation, genetic divergence and possibly speciation, there was good reason to suspect that Bicoxidens may consist of several distinct lineages. On this basis, the mitochondrial cytochrome c oxidase subunit 1 (COI) was used to reconstruct the phylogeny of Bicoxidens and reveal divergent lineages within the genus. Maximum likelihood and Bayesian inference analyses recovered a paraphyletic Bicoxidens phylogram with divergent lineages present in three species – B. friendi, B. flavicollis and B. brincki – suggesting high genetic diversity within the genus. Bayesian genetic cluster analyses suggested the presence of multiple distinct mitochondrial lineages within the genus with four identified in B. flavicollis alone. It was therefore concluded that the divergent lineages observed among Bicoxidens populations may suggest the presence of hidden species.  相似文献   

5.
We used mitochondrial cytochrome b and ND4 genes and 9 microsatellite loci to determine genetic diversity, population structure, evolutionary history, and migration patterns within the Reeves’ butterfly lizard Leiolepis reevesii (Agamidae). Considering molecular-based phylogeographical lineages, we then performed niche equivalency and similarity tests between divergent lineages. Phylogenetic analyses based on mitochondrial DNA (mtDNA) data revealed 2 lineages (A and B) diverging ≈0.84 million years ago and, respectively, restricted to the northern and southern portions of the Wuzhishan and Yinggeling mountain ranges. Lineage B contains individuals from southern Hainan; Lineage A includes individuals from all other localities and can be further divided into 3 clusters according to microsatellite data. The null hypothesis that the 2 lineages shared identical niches was rejected in all niche equivalency tests, indicating niche shifts during genetic divergence. Similarity tests provided evidence of niche conservatism, suggesting that the 2 lineages share more characteristics of their niche spaces than randomly expected. The niche similarity and equivalency tests indicated a complex niche pattern in which both lineages share a main portion of their ecological spaces. The climatic niche of Lineage B represented a marginal and specialized fraction of the entire ecological space of the climatic niche of Lineage A, with warmer conditions. Isolation caused by orogenesis and subsequent niche divergence, together with local adaptation, may have led to genetic differentiation and further lineage sorting in L. reevesii.  相似文献   

6.
Several specimens of the giant deep‐sea isopod genus Bathynomus were collected by a deep‐sea lander at a depth of 898 m near Hainan Island in the northern South China Sea. After careful examination, this material and the specimens collected from the Gulf of Aden, north‐western Indian Ocean, previously reported as Bathynomus sp., were identified to be the same as a new species to the genus. Bathynomus jamesi sp. nov. can be distinguished from the congeners by: the distal margin of pleotelson with 11 or 13 short straight spines and central spine not bifid; uropodal endopod and exopod with distolateral corner slightly pronounced; clypeus with lateral margins concave; and antennal flagellum extending when extended posteriorly reaches the pereonite 3. In addition, Bathynomus jamesi sp. nov. is also supported by molecular analyses based on mitochondrial COI and 16S rRNA gene sequences. The distribution range of the new species includes the western Pacific and north‐western Indian Ocean.  相似文献   

7.
Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of important diseases affecting wild and domestic animals. During the last decade they have played a major role in the epidemiology of the largest bluetongue epizootic ever recorded in Europe, the disease is transmitted between hosts almost exclusively by bites of Culicoides midges and affects both domestic and wild ruminants however severe disease usually occurs in certain breeds of sheep and some species of deer. An accurate vector identification is of major importance in arthropod borne diseases surveillance, as great differences in vectorial capacity are found even between close species. Unfortunately, specialized taxonomic knowledge of Culicoides identification is rarely available in routine surveillance, mainly based on wing morphology. Recently, some European species of Culicoides belonging to the subgenus Avaritia Fox, 1955 and Culicoides Latreille, 1809 have been described as new bluetongue virus vectors.In the present study, by using a fragment of the barcode region (COI gene) we report the presence of up to 11 species within the subgenus Culicoides in Catalonia (NE Spain), a region recently affected by a bluetongue epizootic. The molecular analysis revealed new non-described cryptic species which were grouped in three complexes of morphologically similar species, two in the Pulicaris complex resembling Culicoides pulicaris, two in the Fagineus complex resembling Culicoides fagineus and three in the Newsteadi complex resembling Culicoides newsteadi. The phylogenetic relationships among them showed that cryptic species detected in both Pulicaris and Fagineus complexes were closely related, whereas those in the Newsteadi complex were more distant. Accurate analysis of all species using morphological and molecular approaches resulted in the detection of diagnostic metric traits for cryptic species and the design of several new species-specific single and multiplex PCR assays to identify unambiguously all the species, most of them still lacking a specific molecular diagnosis.  相似文献   

8.
Although it has been suggested that olfaction is closely interconnected with hippocampal systems, whether olfaction regulates spatial memory strategy remains never known. Furthermore, no study has examined how olfaction mediates spatial memory established on the external objects, for example, caches made by scatter-hoarding animals. Here, we experimentally induced nondestructive and reversible olfaction loss of a scatter-hoarding animal Leopoldamys edwardsi, to test whether and how olfaction regulates spatial memory to mediate cache recovery and pilferage. Our results showed that the normal L. edwardsi preferred to pilfer caches of others rather than to recover their own using accurate spatial memory (35.7% vs. 18.6%). Anosmic L. edwardsi preferred to recover the caches they made prior to olfaction loss rather than to pilfer from others relied on spatial memory (54.2% vs. 36.0%). However, L. edwardsi with anosmia showed no preference either to the caches they established after olfaction loss or caches made by others (25.8% vs. 29.1%). These collectively indicate that olfaction loss has a potential to affect new memory formation but not previously established spatial memory on caches. Our study first showed that olfaction modified spatial memory strategy in cache recovery and pilferage behaviors of scatter-hoarding animals. We suggest that future studies pay more attention to the evolution of olfaction and its relationship with spatial memory strategy.  相似文献   

9.
Species of the genus Gynandropaa within the family Dicroglossidae are typical spiny frogs whose taxonomic status has long been in doubt. We used integrative methods, involving morphological and molecular analyses, to elucidate the phylogenetic relationships, and to determine identities and the geographic distribution of each valid species. We obtained DNA sequence data of 5 species of Gynandropaa (complete sequences of the mitochondrial NADH dehydrogenase subunit 2 [ND2] gene, and 890 bp of 12S rRNA and 16S rRNA partial sequences) from 37 localities (including the topotypes of 5 described species) and constructed Bayesian and maximum‐likelihood trees to examine the patterns of phylogeography. A total of 28 morphological variables were taken on 624 specimens. Three clades with clear geographic patterns were recognized: clade C (from south‐western Sichuan Province and central Yunnan Province), clade E (western Guizhou Province and eastern to central Yunnan Province) and clade W (western to southern Yunnan Province). Integrating morphological characteristics and distribution information, the clades W, E and C represent Gynandropaa yunnanensis, G. phrynoides and G. sichuanensis, respectively. We draw the following conclusions: (i) the taxon G. phrynoides, formerly evaluated as a junior synonym of G. yunnanensis, is revalidated herein at the rank of species; (ii) G. liui is a junior synonym of G. sichuanensis; and (iii) G. yunnanensis is a valid species while G. bourreti is probably a subspecies of G. yunnanensis, with the distribution range from Vietnam to southern Yunnan Province. This study clears up the taxonomic status of Gynandropaa and provides important information for understanding the evolution and conservation of these spiny frogs.  相似文献   

10.
The anatomy of the spinal cord segments was studied and recorded for the impala. The root attachment lengths were greatest at C3, T10 and L3 cord segment levels in the respective regions. As to the root emergence length the greatest lengths were observed at C7, T]0> L5 and S1 cord segment levels respectively. The interroot interval was longest at C2, T8 and L1 segments respectively. The longest cord segments were C2, T13, L2 and S2 segments. The widest cord segments of their respective regions were C7, T1, L5 and S1 cord segments. As to segment volume C3, T13, L2 and S1 were the most voluminous cord segments in the respective cord regions. Statistical analysis revealed a high correlation among all of the study parameters suggesting a high degree of multicolinearity. Gross anatomical relationships concerning the location of the spinal cord segments with respect to the vertebrae were studied. The cord segments C], Ts–T4 and Li–L3 were within their vertebral limits. In the impala the spinal cord terminated at the midlevel of S4 vertebra.  相似文献   

11.
Extract

Four species of Kiwi are recognized, one in the North Island and three in the South Island. The North Island species is referred to simply as the North Island Kiwi (Apteryx mantelli).The feathers are black about the shaft and fade into reddish brown. The “coat” of the bird is harsh to the touch. Its southern equivalent is known as the South Island Kiwi (Apteryx australis) and is slightly larger and rather greyer than the North Island bird. The feathers are soft. A little smaller than the North Island Kiwi is the Large Grey or Large Spotted Kiwi (Apteryx haasti),whilst the smallest of this group is the Little Grey or Little Spotted Kiwi (Apteryx oweni).  相似文献   

12.
The scatter‐hoarding behavior of granivorous rodents plays an important role in seed dispersal and seedling regeneration of trees, as well as the evolution of several well‐known mutualisms between trees and rodents in forest ecosystems. Because it is difficult to identify seed hoarders and pilferers under field conditions by traditional methods, the full costs incurred and benefits accrued by scatter‐hoarding have not been fully evaluated in most systems. By using infrared radiation camera tracking and seed tagging, we investigated the benefits and losses of scatter‐hoarded seeds (Camellia oleifera) for 3 sympatric rodent species (Apodemus draco, Niviventer confucianus and Leopoldamys edwardsi) in a subtropical forest of Southwest China during 2013 to 2015. We established the relationships between the rodents and the seeds at the individual level. For each rodent species, we calculated the cache recovery rate of cache owners, as well as conspecific and interspecific pilferage rates. We found that all 3 sympatric rodent species had a cache recovery advantage with rates that far exceeded average pilferage rates over a 30‐day tracking period. The smallest species (A. draco) showed the highest rate of scatter‐hoarding and the highest recovery advantage compared with the other 2 larger species (N. confucianus and L. edwardsi). Our results suggest that scatter‐hoarding benefits cache owners in food competition, supporting the pilferage avoidance hypothesis. Therefore, scatter‐hoarding behavior should be favored by natural selection, and plays a significant role in species coexistence of rodent community and in the formation of mutualism between seeds and rodents in forest ecosystems.  相似文献   

13.
The ocellated lizards in the Timon lepidus/tangitanus/pater complex include the largest lacertids living in continental Europe and North Africa. Long considered a single species (T. pater), the division of the North African ocellated lizards into two species, T. pater in Tunisia and Algeria, and T. tangitanus in Morocco, is now accepted. In this study we investigated the patterns of genetic diversity in T. tangitanus and T. pater across North Africa. We analysed 12s rRNA and 16s r RNA mtDNA fragments of 26 new samples plus 19 sequences from previous studies, using parsimony, likelihood and Bayesian approaches. Our results confirm the two North African species as well-defined entities. Within T. tangitanus from Morocco, three genetically divergent lineages with geographic congruence were uncovered; one in the north, another widely spread across Central Morocco and one in the High Atlas and farther south. A high level of divergence among the Moroccan lineages suggests the split occurred just after the divergence between T. tangitanus and T. pater. Similar patterns have been found in other species, although more studies are needed to understand the biogeographical events shaping the complex diversity in this region.  相似文献   

14.
In this study, we determined six “hotspots” for avian biodiversity conservation in China. We analyzed the distribution patterns of 183 threatened bird species in China in conjunction with geographical data to produce a distribution map that shows the concentrations of threatened species. The six biodiversity hotspots are: the western Tianshan Mountains; the Qilian and Hengduan mountains; southern Anhui, southern Jiangsu, and the Zhejiang Hills; the Songliao Plain and the northern region of the North China Plain; the island of Taiwan; and the island of Hainan. Based on our analysis of a species–habitat matrix, species were determined to be distributed mainly in broadleaved forest, grassland and meadows, urban and agricultural areas, wetlands, and bush. Most species were commonly found to have a range of three to five different habitat types. Apart from the six biodiversity hotspots, six ecological clusters were determined. Protection strategies indicating different levels of habitat priority among the biodiversity hotspots were also recommended.  相似文献   

15.
A practical measure of assessing periods of potential nutritional stress of game species is needed in the management of these species in the Acacia karroo Riparian Thicket of the central Free State. The objectives of the study were to determine Nf concentration of four game species (browsers and mixed feeders) during different seasons, compare Nf with leaf phenology patterns, and assess whether Nf reaches levels at which body condition loss can be expected. A seasonal pattern was observed with the lowest Nf concentrations recorded during late winter, which correlated with the seasonal phenology pattern (leaf carriage) of the winter-deciduous tree species. The Nf concentrations (g N kg?1 dung DM) of giraffe ranged from 18.3 (late winter) to 36.7 (summer) and that of kudu from 13.6 to 33.2. Likewise, the Nf of impala ranged from 16.9 to 28.0 and that of eland from 16.3 to 34.9. Access to evergreen woody species during the late-winter period proved to be essential in avoiding condition loss that corresponds with Nf levels below published critical levels (<16). In the absence of evergreen species, supplementary feeding is essential. Faecal nitrogen proved to be a useful indicator of seasonal trends in the nutritional status of browsing game species.  相似文献   

16.
A novel Bacillus species of Calculus Bovis (cow gallstone) was isolated and identified in this study. Morphological features, bacterial fatty acid analysis using a microbial identification system, carbon source utilization profiles using Biolog system and 16S rDNA sequencing were employed to identify the isolated bacterium. This isolated bacterium was observed to be Gram‐negative, aerobic growing, rod‐shaped and short chain. The results of bacterial fatty acid analysis and physiological characteristics were not matched to the database. The main fatty acids found in the bacterium were 65.96% branched chain saturated fatty acids (iso C11:0, anteiso C11:0 and iso C13:0~anteiso C19:0). The bacterium oxidized 35 carbon sources and weakly responded with 49 of the 95 different carbon sources analyzed with the Biolog identification system. Based on 16S rDNA sequence analysis, this bacterium was classified as a novel Bacillus species.  相似文献   

17.
《Integrative zoology》2017,12(3):186-197
The involvement of communities in ecological studies has been shown to augment conservation efforts, especially for cryptic species. However, there is a lack of studies addressing the utility of incidental sighting records from community members in gaining knowledge on habitat preferences and distribution of suitable habitat for these organisms. This study compares preferences of the Lumholtz's tree kangaroo (Dendrolagus lumholtzi ; LTK), a cryptic rainforest folivore in northeastern Australia, for various habitat and climatic variables derived from data collected during scientific projects to those derived from incidental sighting records using ArcGIS and Maxent. Incidental sighting records suggest that the species uses a wider range of altitudes, annual rainfalls, annual mean temperatures and vegetation types than predicted by scientific studies. Incidental records also show that the species can persist in areas of lower rainfall during the wettest month and lower minimum temperature during the coldest month. Both data place the species within a comparable range of rainfalls during the driest month, maximum temperatures of the warmest month and soil types. When using identified preferences to assess the extent and distribution of suitable habitat, incidental records predicted more areas of suitable habitat than scientific records with an overlap of up to 91% between them. The present study proves that incidental sighting records can be a valuable part of the study of cryptic species and should be considered complementarily alongside scientific studies to obtain comprehensive ecological information of a species that can assist in its conservation.  相似文献   

18.
The detection of gelatinase and β‐haemolysis activities was carried out in 83 faecal enterococci (43 Enterococcus faecalis, 33 E. faecium, five E. durans and two E. hirae) of poultry origin. In addition, the presence of genes of the gelE–fsrABC locus and of the cyl operon (cylLL, cylLS, cylA, cylB and cylM) were studied by polymerase chain reaction and correlated with gelatinase and β‐haemolysis production, respectively. Most of our E. faecalis isolates were gelatinase‐positive (88%), being this activity not frequent in the other enterococcal species (2.5%). Only one of the 33 E. faecium isolates showed a positive gelatinase reaction. All enterococci that showed gelatinase activity harboured the gelE and fsrABC genes, although these genes were also detected in four E. faecalis and one E. durans gelatinase‐negative isolates. Most of our non‐E. faecalis gelatinase‐negative isolates did not harbour gelE–fsrABC genes. A high proportion of faecal enterococci of poultry origin harboured genes of the cyl operon (71%), although only 7% contained the five cyl tested genes (all of them E. faecalis). Only one isolate of our series could express β‐haemolysis, harbouring the whole cyl operon. The cylLS genotype was the most prevalent in our enterococci (39%) and also the most prevalent among our E. faecalis isolates (60%). Other genotypes detected were the following ones (% of enterococci): cylA + cylB + cylM (13%), cylLL + cylA (4%), cylLL (4%), cylLL + cylA + cylB + cylM (2%), cylLL + cylA + cylM (1%) and cylA + cylM (1%). Both phenotypic and genotypic assays are important to evaluate the virulence potential of enterococci.  相似文献   

19.
The sharp-nosed reed frog is widespread in Africa. Although currently recognized as one species, suggestions have been made that more than one species might exist. We analysed 237 calls of 69 males from 19 localities in the western to southern parts of Africa. Calls fall into three groups, which we recognize as cryptic species. Of eight published sound spectrograms, all can be assigned to one of the three species. We recognize Hyperolius nasutus, distributed from western Africa to the Okavango Delta in Botswana; Hyperolius viridis, from the central highlands of northwestern Zambia to southern Tanzania; and Hyperolius acuticeps> which occurs from the Ivory Coast to the southeastern coast of South Africa. We assign published names to the synonymies of these three species. No call data are available for populations in the Congo basin.  相似文献   

20.
Understanding life history patterns, individual fitness and population fitness can assist with conservation of endangered species. Field data on life history traits (i.e. age specific fecundity, age specific mortality, age at first reproduction, litter size and adult life expectancy) were collected from 121 Hainan Eld's deer (Cervus eldi hainanus Thomas, 1918), an in situ herd of an endemic, rare and endangered cervid inhabiting Bangxi Natural Reserve of Hainan Island, from 1990 to 2002. First, we constructed a dynamic life table to analyze the life history pattern of the population, which showed that the difference between the average lifespan of males and females was not significant (P > 0.05), and that the difference between the average lifespan of the whole Hainan Eld's deer population and that of other Eld's deer populations living in South Asia (P > 0.05), North America (P > 0.05) and Europe (P > 0.05) was not significant. Second, we used individual reproductive success or number of offspring of a male over its lifetime to estimate male individual fitness. Statistic analysis showed that male individual fitness was not significantly correlated with total antler velvet mass. Third, we used the population intrinsic rate of increase to measure population fitness, and population fitness of Hainan Eld's deer was compared with similar indexes of 5 other cervid species. Hainan Eld's deer population fitness index was 0.012, the second lowest value relative to other cervids. Results indicated that this rare species is still endangered and is in need of additional protection.  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