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 0 毫秒
1.
Two and perhaps three taxa of Lissotriton newt occur in Turkey. Their species status is controversial. The distribution of these taxa and the taxonomic status of each are reviewed and discussed. A database of 128 Turkish Lissotriton localities was compiled and species distribution models were constructed. We reiterate that the presence of Lissotriton (vulgaris) lantzi in Turkey is disputed and needs confirmation. The range of Lissotriton (vulgaris) kosswigi is restricted to north-western Anatolia – given the small global range of this Turkey endemic, a closer look at its conservation status is warranted. The distribution of Lissotriton vulgaris schmidtleri covers western Asiatic and European Turkey. The findings support an allopatric distribution of the Turkish Lissotriton species. We reflect on the biological significance of previously reported morphological intermediates between Lissotriton (vulgaris) kosswigi and Lissotriton vulgaris schmidtleri in the light of the recent proposal to recognize kosswigi at the species level. The available data are in line with species status for Lissotriton (vulgaris) lantzi and Lissotriton (vulgaris) kosswigi. Although Lissotriton vulgaris schmidtleri is a genetically diverged taxon as well, the extent of gene flow with parapatric European Lissotriton taxa is as yet unknown.  相似文献   

2.
We explored the phylogenetic signal of skull size and shape in alpine newts from the Balkans, a group of European newts that, in spite of their considerable phylogeographic substructuring (as inferred from previous DNA analyses), maintain a conserved phenotype. In terms of skull shape disparity, geometric morphometrics show that the dorsal cranium carries a significant phylogenetic signal, the most notable evidence in this present study. On the contrary, no phylogenetic signal in the shape of the ventral cranium was found. This result indicates that the variation in the shape of the ventral cranium is more prone to other factors and processes, such as adaptations to local environments rather than phylogenetic constraints. Variation in skull size within alpine newts seems to be independent from phylogenetic constraints.  相似文献   

3.
We used a phylogenetic perspective in an examination of the direction and extent of sexual dimorphism in body size and body shape in European newts from the Balkan Peninsula (alpine newts, Mesotriton alpestris; crested newts, Triturus cristatus superspecies; smooth newts, Lissotriton vulgaris). We found a strong, female‐biased sexual size dimorphism (SSD) in the analysed clades of alpine newt, whereas within crested newts we found a less stringent female‐biased SSD in Triturus carnifex, Triturus macedonicus and Triturus karelinii, and no significant SSD in T. cristatus or Triturus dobrogicus. Among the smooth newts, we found male‐biased SSD in Lissotriton vulgaris vularis and Lissotriton vulgaris greacus and no SSD in Lissotriton vulgaris meridionalis. Most of these newts also exhibit a significant sexual dimorphism in body shape, which varied more randomly than body size, regardless of SSD level. Female and male body size as well as the degree of SSD displayed statistically significant phylogenetic signal, while sexual dimorphism in body shape was phylogenetically independent. The relationship between independent contrast data for female size and male size indicated that SSD in European newts could be driven by a disproportionate increase in female size as increase in female size was not accompanied by a proportional increase in male size.  相似文献   

4.
Tissue samples of Mesotriton alpestris veluchiensis were collected from 11 localities in Greece, and the sequences of two mitochondrial genes (cytochrome b and 16S rRNA), as well as frequencies of 18 allozyme loci, were used in order to describe levels and patterns of genetic variation, identify possible evolutionary units, and reveal aspects of their conservation status. Two major lineages, displaying considerable amount of genetic differences, were supported by both analyses. These lineages, which have been geographically separated since the middle Pleistocene, constitute separate Evolutionary Significant Units (ESUs) and correspond to populations from the Greek mainland and Peloponnisos, respectively. The particularly high inter-population differentiation within each region implies long-term isolation in fragmented habitats, while severe bottlenecking is proposed to have resulted in the observed lack of heterozygotes in the majority of populations. Conservational implications are also discussed, particularly in relation to environmental factors and human activities, which seem to have contributed to the genetic impoverishment of the most marginal populations studied.  相似文献   

5.
The identification of the conventionally accepted species of Clavulina (Cantharellales, Basidiomycota) in Europe (Clavulina amethystina, Clavulina cinerea, Clavulina cristata, and Clavulina rugosa) is often difficult and many specimens are not straightforwardly assignable to any of those four species, which is why some authors have questioned their identity. In order to assess the status of those species, a morphological examination was combined with the molecular analysis of the ITS region. The same six major clades were obtained in the Bayesian and parsimony phylogenetic analyses, and all six clades were well-supported at least by one of the analyses. Morphological characters, such as the overall branching pattern, the presence and intensity of grey colour, the cristation of the apices, and basidiospore size and shape were to various extents correlated with the phylogenetic signal obtained from the ITS region. The congruence between the molecular analyses and morphology, rather than geographical origin, suggests the existence of several species that can be delimited using a combined phylogenetic and morphological species recognition. The analyses revealed that C. cristata and C. rugosa are well-delimited species. In contrast, more than one taxa could be subsumed under the names C. amethystina and C. cinerea, the taxonomical complexity of which is discussed. The ITS region is proved to be adequate to separate phylogenetic species of Clavulina.  相似文献   

6.
An analysis of 30 craniological characters of Eurasian badgers (Meles spp.) revealed different levels of sexual size dimorphism (SSD) and geographic variation in the three different species. SSD is displayed mostly in the general size of the skull (condylobasal length, zygomatic width, width of rostrum, and cranial height) and mandible (height of the vertical mandibular ramus, total length of the mandible, and length between the angular process and infradentale), and in some dental characters (length of the upper molar M1). The most stable size dimorphism is manifested in the size of the canines, which is pronounced in all studied samples. SSD is not apparent in the length of the auditory bulla, the postorbital width, the minimum palatal width, the length of the lower molar M2, and the talonid length of the lower carnassial tooth M1.In both the European badgers, Meles meles, and the Asian badgers, Meles leucurus, two geographic forms that differ in the degree of SSD have been found. The most pronounced SSD of cranial characters is found in the Transcaucasian form of Meles meles and the Far-Eastern form of Meles leucurus. In the large European form of Meles meles, SSD is less pronounced in both absolute and relative criteria than in the smaller Transcaucasian form. An analogous situation is observed in the larger Siberian and smaller Far-Eastern forms of Meles leucurus. In the Japanese badgers, Meles anakuma, a downsizing of the skull is accompanied by a decrease in SSD (except in canine size) in comparison to the continental species. The significant differences in the manifestation of SSD in the Eurasian badgers support an earlier hypothesis (Abramov, 2001. Proc. Zool. Inst. Russ. Acad. Sci. 288, 221-233; Abramov, 2002. Russ. J. Theriol. 1 (1), 57-60; Abramov, 2003. Small Carnivore Conserv. 29, 5-7) that Meles meles, Meles leucurus, and Meles anakuma are separate species. The differences in the level of SSD among and within these three species of badgers may be attributed not to differences in the diet or social structure, but to the history of speciation events and formation of intraspecific distribution ranges.  相似文献   

7.
8.
Snails in the closely related trochid genera Phorcus Risso, 1826 and Osilinus Philippi, 1847 are ecologically important algal grazers in the intertidal zone of the northeastern Atlantic Ocean and Mediterranean Sea. Here we present the first complete molecular phylogeny for these genera, based on the nuclear 28S rRNA gene and the mitochondrial 16S rRNA and COI genes, and show that the current classification is erroneous. We recognize nine species in a single genus, Phorcus: estimated by BEAST analysis, this arose 30 (±10) Ma; it consists of two subgenera, Phorcus and Osilinus, which we estimate diverged 14 (±4.5) Ma. Osilinus kotschyi, from the Arabian and Red Seas, is not closely related and is tentatively referred to Priotrochus Fischer, 1879. Our phylogeny allows us to address biogeographical questions concerning the origins of the Mediterranean and Macaronesian species of this group. The former appear to have evolved from Atlantic ancestors that invaded the Mediterranean on several occasions after the Zanclean Flood, which ended the Messinian Salinity Crisis 5.3 Ma; whereas the latter arose from several colonizations of mainland Atlantic ancestors within the last 3 (±1.5) Ma.  相似文献   

9.
Phylogenetic relationships in a group of 21 African rodent species designated as the Praomys group (Murinae) were investigated using morphological characters and sequence data from the complete mitochondrial cytochrome b gene and nuclear IRBP gene fragment (840bp). The molecular results confirm the monophyly of the Praomys group, including the species Malacomys verschureni, while the other Malacomys species appear very divergent. The basal relationships within the Praomys group are poorly resolved, suggesting a rapid radiation at about 7-9 million years ago based on genetic divergence rates calibrated from the fossil record. Discrepancies between molecular and morphological results probably reflect of numerous convergences as well as variations in the rates of morphological evolution among lineages. Reconstructions of the ancestral character states suggest a savannah origin for the Praomys group, along with some morphological traits conserved by stasis in savannah taxa. At the same time, forest taxa seem to be characterized by an accelerated morphological evolution, with acquisition of convergent adaptive characters.  相似文献   

10.
In the present study, we investigated the degree of congruence between phylogeny, as inferred from mitochondrial (mt)DNA sequences, and cranium shape variation of crested newts (Triturus cristatus superspecies) in the Balkans. These newts belong to four phylogenetic clades defined by mtDNA analysis, and significantly differed in cranial shape. Allometry explained a high percentage of shape variation in crested newts. The clade‐specific allometric slopes significantly diverged for both the ventral cranium and dorsal cranium, indicating that differences in shape between clades could not be a simple consequence of their difference in size. The analysis of hierarchical and spatial variation showed similarity in the patterns of global and spatially localized hierarchical variation of cranial shape. We also found significant congruence between the pattern of cranial shape variation and molecular phylogeny. The differences in morphology of Triturus dobrogicus in comparison to other crested newt clades, including marked differences in cranium shape, is discussed in the context of the evolution and ecology of crested newts. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 348–360.  相似文献   

11.
We report a molecular re-assessment of the classification of the nightjars which draws conclusions that are strongly at odds with the traditional, morphology-based classifications. We used maximum likelihood and Bayesian methods to compare the cytochrome b gene for 14 species from seven of the 15 genera of the Caprimulgidae and partial cytochrome b sequence data was available for a further seven species including three further genera. We found that within the Caprimulgidae there were four geographically isolated clades with bootstrap support greater than 70%. One of these clades contained just Chordeiles species, the remaining three clades each contained a mixture of genera including Caprimulgus sp. A clade of exclusively South American nightjars included the genera Caprimulgus, Uropsalis, Eleopthreptus and Hydropsalis. A clade of African and Eurasian birds included Caprimulgus and Macrodipteryx. Phalaenoptilus nuttallii and Caprimulgus vociferous formed a clade of North American birds. Two ecological factors appear to make morphological classification potentially misleading: first, the apparent retention of primitive anti-predator and foraging-related traits across genetically divergent groups; second, rapid divergence in other traits, especially those related to mating, which generate high levels of morphological divergence between species that are genetically very similar. The cytochrome b data suggests that the genus Caprimulgus is not monophyletic and is restricted to Africa and Eurasia and that Caprimulgus species from outside this area have been misclassified as a consequence of retention of primitive adaptations for crepuscular/nocturnal living. Some other genera also appear to have little support from the cytochrome b data.  相似文献   

12.
The present study presents the morphology, histology, and the dynamics of vitellogenesis in females of the tick Amblyomma triste. The ovary in this species is of the panoistic type, therefore it lacks nurse cells. It is composed of a layer of epithelial cells that outwardly form the wall of the ovary, but also originate the pedicel, the structure that attaches the oocytes to its external margin, as well the oocytes themselves. In Amblyomma triste, the oocytes develop in four synchronic stages, which differs from the process in other tick species. The classification of the stages of the oocytes was carried out based on the presence of four morphologic characteristics: cytoplasm appearance; site of the germ vesicle; presence, quantity, and constitution of the yolk granules and presence of chorium.  相似文献   

13.
Palaemon carteri (Gordon, 1935) and Palaemon ivonicus (Holthuis, 1950) are morphologically similar species of South American freshwater shrimps. Past studies have questioned the taxonomic status of both species, which are supposed to have partially sympatric geographic distributions in the Amazon basin. We analyzed a 550 bp fragment of the mitochondrial 16S rRNA gene from these Amazonian Palaemon species as well as from 11 palaemonids as the outgroup. Additionally, we checked diagnostic characters of the genus and family as well as other morphological characters that have been little explored before. Palaemon carteri and Palaemon ivonicus are allocated in two sister lineages, with wide genetic divergence and little morphological differentiation. The divergence time between these lineages was estimated as approximately 10 million years ago. Both molecular and morphological data support the taxonomic validity of both Palaemon carteri and Palaemon ivonicus, refuting the hypothesis of synonymy. In addition, a new species, Palaemon yuna sp. n., closely related to Palaemon ivonicus, is described. Our findings indicate that these species can be differentiated using the projection of the anterolateral margin and anterolateral spine of the first antennular segment, shape of the rostrum, and relative size of the appendix masculina.  相似文献   

14.
Knowledge of the social structure of a population is important for a range of fundamental and applied purposes. Group characteristics and population structure of chital (Axis axis) and sambar (Rusa unicolor) were studied in a deciduous habitat of Mudumalai Tiger Reserve, Western Ghats, India, during 2008-2009. Vehicle transects were monitored monthly to gather information on group-size and age-sex composition of chital and sambar. The average mean group size and crowding for chital and sambar was 13.1 ± 0.5 (n = 1020), 3.6 ± 0.2 (n = 377) and 33.3, 11.0 respectively. The average adult male:adult female:fawn ratio was 63.4:100:22.3 (n = 9391) and 43.9:100:23.7 (n = 1023) in chital and sambar respectively. The mean group size of chital and sambar varied significantly between seasons (Kruskal-Wallis test, p = <0.001). Peak fawning season was observed from February to May for chital and May to August for sambar. Group's sex-age composition influenced group formation in both species between seasons at different level. Adult male and fawn were the important predicting variables of change in group size. Skewed female sex ratio was probably due to selective male predation by large predators. Although fawning occurred throughout the year, both species showed seasonality in fawning. The above mentioned patterns differed between species depending upon their ecological adaptation in foraging strategies and habitat preference.  相似文献   

15.
The snails Lymnaea columella and Lymnaea cousini have both been reported as intermediate hosts of Fasciola hepatica in Colombia. The effect of the exposure to the parasite on survival, fecundity and size of these snails was evaluated by means of experimental infections and the life history traits of control and exposed groups were compared. Infection rates were 82.2 and 34% for L. columella and L. cousini, respectively. A reduction in fitness was observed in both species when exposed to the parasite: fecundity alone was reduced in L. columella whereas in L. cousini there was also a decline in survival rate. Unlike other studies, increased size was not observed in either species. On the contrary, a reduction in growth rate was observed in L. columella.  相似文献   

16.
Tylototriton shanjing Nussbaum, Brodie & Yang, 1995 was described as a distinct species hidden before under the widely distributed T. verrucosus Anderson, 1871. Therefore, papers published before 1995, including those on reproductive biology, could not distinguish between these two close relatives. Consequently, data on the reproductive biology of T. shanjing are scarce. Here, we report on the first captive breeding of T. shanjing in the Aquarium of the Cologne Zoo, and we document the ontogenetic developmental stages and describe the larva for the first time. Moreover, we give a literature review for both T. verrucosus and T. shanjing and compare our data with published information referring undoubtedly to the latter species. To avoid future misidentifications and to facilitate the composition of breeding groups, we present an identification key for the East Asian salamandrid genera in general, and for the species of Tylototriton in particular.  相似文献   

17.
There is need for efficacious biocontrol agents for aphids in commercial orchards. As a preliminary step to this end we determined the virulence of several Hypocreales fungi to pecan aphids. In the first experiment we tested the virulence of Isaria fumosorosea (ARSEF 3581) blastospores to three pecan aphids Monellia caryella, Melanocallis caryaefoliae, and Monelliopsis pecanis under laboratory conditions. Rates of 1 × 107 or 1 × 108 spores per ml were applied in 2 ml via a spray tower to 90 mm Petri dishes containing 10 aphids each. Mortality and mycosis were determined after 24, 48 and 72 h. Treatment effects were observed by 48 h post-application, and by 72 h the higher application rate caused >90% mortality and mycosis in M. caryella and M. caryaefoliae, whereas <70% was observed in M. pecanis.We conducted two subsequent experiments (Experiments 2 and 3), using the same methodology, to compare the virulence of several Hypocreales species and strains against the aphid of primary economic concern to most pecan growers, M. caryaefoliae. In Experiment 2, we compared blastospores and conidia of two I. fumosorosea strains (ARSEF 3581 and ATCC 20874 [= strain 97]). The blastospores of ARSEF 3581 and conidia of ATCC 20874 showed higher virulence than other treatments and thus were included in Experiment 3, which also compared the virulence of conidia of Beauveria bassiana (GHA strain) and Metarhizium anisopliae (F52 strain). Results in Experiment 3 indicated the highest virulence in I. fumosorosea 3581 blastospores and M. anisopliae (F52) followed by I. fumosorosea (20874) conidia. The detection of pathogenicity to pecan aphids establishes the potential for commercial usage and additional study. Results reported here will narrow treatments to test in future greenhouse and field trials.  相似文献   

18.
An abundant ichnological material composed of xiphosuran trackways and isolated traces was discovered in Upper Jurassic limestones from the Causses Basin (Causse Méjean, Lozère, France). The morphology of the imprints supports their identification as Kouphichnium isp. In contrast to the most frequent case, the trackways are composed of omnipresent pusher imprints sometime associated with leg traces, but with no telson mark. We argue that this pattern reflects actual surface traces rather than an incomplete set of undertracks. The size distribution of the sampled ichnites is broadly bimodal. This is best explained by sexual dimorphism, a phenomenon frequently observed in modern xiphosurans. Analysis of the trace fossils further suggests that several growth stages are recorded and that the horseshoe crabs were walking in a protected and flat environment like a lagoon. This area, certainly close to a mating ground, was occasionally affected by a continental influence. The biometric study of the tracks suggests a gigantic size for the trackmakers whose body may have reached 84 cm in length. This discovery complements the few reports on other gigantic horseshoe crabs in the Jurassic of Western Europe, thus casting doubt on the postulated increase in body size from the Palaeozoic to the Recent. Furthermore, a literature review shows that there are still major gaps in the record of limulid body-fossils and tracks. Thus, neither of these archives can be taken at face value for quantifying the body-size evolution of horseshoe crabs.  相似文献   

19.
Systematic excavations at the site of the Sima de los Huesos (SH) in the Sierra de Atapuerca (Burgos, Spain) have allowed us to reconstruct 27 complete long bones of the human species Homo heidelbergensis. The SH sample is used here, together with a sample of 39 complete Homo neanderthalensis long bones and 17 complete early Homo sapiens (Skhul/Qafzeh) long bones, to compare the stature of these three different human species. Stature is estimated for each bone using race- and sex-independent regression formulae, yielding an average stature for each bone within each taxon. The mean length of each long bone from SH is significantly greater (p < 0.05) than the corresponding mean values in the Neandertal sample. The stature has been calculated for male and female specimens separately, averaging both means to calculate a general mean. This general mean stature for the entire sample of long bones is 163.6 cm for the SH hominins, 160.6 cm for Neandertals and 177.4 cm for early modern humans. Despite some overlap in the ranges of variation, all mean values in the SH sample (whether considering isolated bones, the upper or lower limb, males or females or more complete individuals) are larger than those of Neandertals. Given the strong relationship between long bone length and stature, we conclude that SH hominins represent a slightly taller population or species than the Neandertals. However, compared with living European Mediterranean populations, neither the Sima de los Huesos hominins nor the Neandertals should be considered ‘short’ people. In fact, the average stature within the genus Homo seems to have changed little over the course of the last two million years, since the appearance of Homo ergaster in East Africa. It is only with the emergence of H. sapiens, whose earliest representatives were ‘very tall’, that a significant increase in stature can be documented.  相似文献   

20.
Many alpine plants display a generalist pollination system where almost any available flower visitor could act as a legitimate pollinator. Co-flowering related plant species displaying a generalized pollination system can decrease their fitness due to interspecific mating. In this study, we determine the difference in diversity and composition of the pollination systems of two co-occurring species endemic to the alpine region of the Sierra Nevada (SE Spain), Erysimum nevadense Reut. and Erysimum baeticum baeticum (Heywood) Polatschek (Brassicaceae), and check for the potential role of floral and plant traits in explaining the observed differences. For this, we labeled 30 plants in two populations of each plant species located in the same area. We determined flower visitor assemblage by sampling all insects approaching the flowers and contacting the sexual organs during 60-min surveys. We found that the diversity of the pollinator assemblage was similar between the two studied wallflower species, both species showing a much generalized pollination system. However, the composition of the pollinator assemblage was different, since the flowers of E. nevadense were visited mostly by beetles and in a lesser extent by hover-flies, whereas the flowers of E. baeticum baeticum were visited mostly by ants and bees. Interestingly, flower traits varied between species, with E. nevadense displaying yellow, smaller and shallower flowers and E. baeticum baeticum displaying purple, large and deeper flowers. These findings suggest that differences in floral traits can explain the observed differences in the composition of the pollinator assemblage between both wallflower species.  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