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1.
Accurate delimitation of species is a critical first step in protecting biodiversity. Detection of distinct species is especially important for groups of organisms that inhabit sensitive environments subject to recent degradation, such as creeks, springs, and rivers in arid or semi-desert regions. The genus Dionda currently includes six recognized and described species of minnows that live in clear springs and spring-fed creeks of Texas, New Mexico (USA), and northern Mexico, but the boundaries, delimitation, and characterization of species in this genus have not been examined rigorously. The habitats of some of the species in this genus are rapidly deteriorating, and many local populations of Dionda have been extirpated. Considering the increasing concerns over degradation of their habitat, and pending a more detailed morphological revision of the genus, we undertook a molecular survey based on four DNA regions to examine variation over the range of the genus, test species boundaries, and infer phylogenetic relationships within Dionda. Based on analyses of two mitochondrial (cytb and D-loop) and two nuclear (Rag1 and S7) DNA regions from specimens collected throughout the range of Dionda, we identified 12 distinct species in the genus. Formerly synonymized names are available for two of these species, and four other species remain undescribed. We also redefine the known range of six species. The limited distribution of several of the species, coupled with widespread habitat degradation, suggests that many of the species in this genus should be targets for conservation and recovery efforts.  相似文献   

2.
Apathya is a lacertid genus occurring mainly in south-east Turkey and its adjacent regions (part of Iran and Iraq). So far two morphological species have been attributed to the genus; A. cappadocica (with five subspecies, A. c. cappadocica, A. c. muhtari, A. c. schmidtlerorum, A. c. urmiana and A. c. wolteri) and A. yassujica. The first species occupies most of the genus’ distribution range, while A. yassujica is endemic of the Zagros Mountains. Here, we explored Apathya’s taxonomy and investigated the evolutionary history of the species by employing phylogenetic and phylogeographic approaches and using both mitochondrial (mtDNA) and nuclear markers. The phylogenetic relationships and the genetic distances retrieved, revealed that Apathya is a highly variable genus, which parallels its high morphological variation. Such levels of morphological and genetic differentiation often exceed those between species of other Lacertini genera that are already treated as full species, suggesting the necessity for a taxonomic revision of Apathya. The phylogeographical scenario emerging from the genetic data suggests that the present distribution of the genus was determined by a combination of dispersal and vicariance events between Anatolia and Southwest Asia dating back to the Miocene and continuing up to the Pleistocene. Key geological events for the understanding of the phylogeography of the genus are the movement of the Arabian plate that led to the configuration of Middle East (orogenesis of the mountain ranges of Turkey and Iran) and the formation of Anatolian Diagonal.  相似文献   

3.
The supralittoral environment, at the transition between sea and land, is characterized by harsh conditions for life. Nonetheless, evolution of terrestrial isopods (Oniscidea), the only group of Crustacea fully adapted to live on land, appears to have involved a transitional step within the supralittoral. The two most basal oniscidean lineages (Ligiidae and Tylidae) have representatives that successfully colonized the supralittoral. One of them is the genus Tylos, which is found exclusively in supralittoral sandy beaches from tropical and subtropical coasts around the world. Comprehensive phylogenetic hypotheses for this genus are lacking, which are necessary for understanding the evolution and biogeography of a lineage that successfully diversified in the harsh sea-land interface. Herein, we studied the phylogenetic relationships among 17 of the 21 currently recognized species of the genus Tylos, based on sequences from four mitochondrial genes (Cytochrome Oxidase I, Cytochrome b, 16S rDNA, and 12S rDNA). Maximum Likelihood and Bayesian phylogenetic analyses identified several lineages with deep divergences and discrete geographic distributions. Phylogenetic and distributional patterns of Tylos provide important clues on the biogeography and evolution of this group. Large divergences among the most basal clades are consistent with ancient splits. Due to the biological characteristics of Tylos, which likely prevent dispersal of these isopods across vast oceanic scales, we argue that tectonic events rather than trans-oceanic dispersal explain the distribution of Tylos in different continents. Overwater dispersal, however, likely enabled range expansions within some basins, and explains the colonization of volcanic oceanic islands. Present-day distributions were also likely influenced by sea level and climate changes. High levels of allopatric cryptic genetic differentiation are observed in different regions of the world, implying that the dispersal abilities of Tylos isopods are more limited than previously thought. Our results indicate that a taxonomic revision of this group is necessary.  相似文献   

4.
Anaphalis is the largest Asian genus in the tribe Gnaphalieae (Asteraceae) and has its greatest species diversity in the eastern Himalayas. The nuclear internal and external transcribed spacers were sequenced for Anaphalis species, with an emphasis on the eastern Himalayan taxa to examine the monophyly and construct the phylogenetic relationships of and within the genus. The results suggest that all species of Anaphalis are nested with Helichrysum, showing a close relationship with a Mediterranean–Asian group of Helichrysum. Although the monophyly of Anaphalis is only weakly supported, two clades within the genus are well recognized, each consisting of two subgroups. The inferred phylogenetic relationships within Anaphalis correspond to the shape of leaf base, rather than the morphology of the capitula and phyllaries that are usually used for species delimitation and classification in the genus. All four subgroups of Anaphalis are common and diversified in the eastern Himalayas with multiple dispersals out of this region. The sole North American species of Anaphalis is best hypothesized to be the result of long-distance dispersal or overland migration via Bering land bridge from Asia. Our analyses suggest that the extant distribution of Anaphalis has most likely resulted one radiation into the eastern Himalayas followed by repeated independent dispersals and/or radiations mostly into eastern Asia but also into the western Himalayas, North America, and southeast Asia.  相似文献   

5.
In this paper, the analysis of the current distribution of species, or species-groups, of the Western–Palaearctic genus Amphimallon Berthold, 1827, based on a phylogenetic hypothesis recently provided and relevant paleogeographical events that occurred in the Mediterranean Basin from Late Paleogene (35 Myr BP) to the present, supports a biogeographical scenario to explain species diversity within this genus. The center of origin of this genus is hypothesized to be in the Iberian Peninsula. Microplate fragments drifting from the Iberian Peninsula, successive landmass suture events between the Eastern and Western Mediterranean Basins, separation of Tethys and Paratethys Oceans, re-establishment of marine connections, uplift of the Alps, and drying out of the Mediterranean are hypothesized as the principal events allowing dispersal of populations throughout Mediterranean Basin and biogeographical vicariances within the genus Amphimallon.  相似文献   

6.
Michel Sartori 《ZooKeys》2014,(420):19-39
Three species belonging to the genus Thalerosphyrus Eaton, 1881 are reported from Java and Sumatra. The nymphs of Th. determinatus (Walker, 1853) from Java, Th. sinuosus (Navás, 1933) from Java and Sumatra and Th. lamuriensis Sartori, 2014 from Sumatra are redescribed. The egg morphology of the three species is also presented for the first time. A key to the nymphs is proposed. General considerations on the composition of the genus Thalerosphyrus in the Oriental Realm are given. The distribution of the genus is greatly expended, and currently ranges over the Himalaya and Sumbawa in the Sunda Islands.  相似文献   

7.
Wilkinsonellus Mason is a relatively small Pantropical genus of braconid parasitoid wasps within the subfamily Microgastrinae. Most of the currently described species are from the Palaeotropics; however, previous records were absent from Fiji. Here, the first three Wilkinsonellus species from Fiji are described: Wilkinsonellus corpustriacolor sp. n., Wilkinsonellus fijienis sp. n. and Wilkinsonellus nescalpura sp. n. The material was collected by Malaise traps set up in a quite variety of ecosystems (wet zone, dry zone and coastal forests) throughout the archipelago. With these records, Fiji represents the easternmost known distribution of the genus in the Indo-Pacific Region. A key to all of the currently known Wilkinsonellus species is included to facilitate species identification.  相似文献   

8.
Taxonomic considerations are given for the genus Lissothus Vachon, 1948 (Scorpiones, Buthidae). Two species are currently known, Lissothus bernardi Vachon, 1948 from Libya and Lissothus occidentalis Vachon, 1950 from Mauritania. In this contribution, a new species, Lissothus chaambi sp. n., is described from the desert of Central Algeria. The new species is most closely related to L. bernardi. The geographical distribution of the genus is discussed.  相似文献   

9.
Bythinella is a species-rich genus of spring-snails, having a wide range in Europe and Asia Minor. The genus contains several endemic species with narrow ranges, creating interest from a conservation perspective as well as their use as a model for research into biogeographical patterns and evolutionary development. Most of the species of the genus Bythinella are difficult to distinguish by traditional methods due to their similar shell morphology. In previous studies, molecular approaches often came to conclusions that contradicted those from a morphology-based approach, hence the classification of species of Bythinella has been in dispute. Bythinella pannonica has clearly distinct shell morphological features, and consequently is one of the few species of undisputed taxonomic status within this genus. As an important step towards clarifying the systematics of this genus, we have attempted to describe the structure and spatial pattern of diversity of the mitochondrial COI marker within this species, in the hope of applying these findings generally to the whole genus. Molecular results support the monophyly of B. pannonica within the genus. The largest pairwise intraspecific COI sequence difference was almost 5 %, much larger than the value of 1.5 % previously proposed as a barcoding threshold for delimitation of Bythinella species. This finding suggests that incautious application of barcoding might lead to incorrect taxonomic conclusions. Within B. pannonica there are two deeply divergent intraspecific clades, the spatial distribution of which has been shaped by fragmentation, as well as by short and long distance dispersal events. These two clades have not been found syntopically but, as a peculiar feature of this taxon, they are able to persist in nearby habitats. We have demonstrated that the patchy distribution of suitable habitats and the restricted, but non-zero gene flow amongst the populations might play a key role in maintenance of the observed genetic structure of this species.  相似文献   

10.
A phylogenetic analysis of all 17 extant species of the clawed lobster genus Metanephrops based on mitochondrial 12S rRNA, 16S rRNA and cytochrome c oxidase I, and nuclear histone H3 gene sequences supports the morphological groupings of two of the traditional groups of the genus (the binghami and japonicus groups) but refutes monophyly of the other two groups (the arafurensis and thomsoni groups). The results in general support a recent morphology-based cladistic analysis of this genus except that this study suggests M. neptunus to be a basal rather than a derived species as indicated in the morphological analysis. This species is genetically diverse over its geographical range. Moreover, the two color forms of M. thomsoni are genetically distinct, most likely representing different species. The molecular phylogeny and current distribution pattern of the extant species, together with the fossil record, suggest that the genus originated in the Antarctica in the Cretaceous, followed by diversification and dispersal along the continental shelf of different continents as a result of the vicariant events associated with the breakup of the Southern Temperate Gondwana since Late Cretaceous.  相似文献   

11.
Two North American species of green lacewings have undergone a number of changes in their generic assignments and are currently classified as incertae sedis. Here we demonstrate that adults (both sexes) and larvae of these species share a set of features that distinguishes them from currently described genera. Thus, to promote nomenclatural stability in Chrysopidae, we describe Kymachrysa, a gen. n. that contains the two species – Kymachrysa intacta (Navás), comb. n. and Kymachrysa placita (Banks), comb. n.. Also, we present modifications for the current generic-level key, illustrations, as well as biological information for identifying the genus and its known species.  相似文献   

12.
Rhabdiasidae Railliet, 1915 is a globally distributed group of up to 100 known species of nematodes parasitic in amphibians and reptiles. This work presents the results of a molecular phylogenetic analysis of 36 species of Rhabdiasidae from reptiles and amphibians from six continents. New DNA sequences encompassing partial 18S rDNA, ITS1, 5.8S rDNA, ITS2 and partial 28S rDNA regions of nuclear ribosomal DNA were obtained from 27 species and pre-existing sequences for nine species were incorporated. The broad taxonomic, host and geographical coverage of the specimens allowed us to address long-standing questions in rhabdiasid systematics, evolution, geographic distribution, and patterns of host association. Our analysis demonstrated that rhabdiasids parasitic in snakes are an independent genus sister to the rest of the Rhabdiasidae, a status supported by life cycle data. Based on the combined evidence of molecular phylogeny, morphology and life cycle characteristics, a new genus Serpentirhabdias gen. nov. with the type species Serpentirhabdias elaphe (Sharpilo, 1976) comb. nov. is established. The phylogeny supports the monophyly of Entomelas Travassos, 1930, Pneumonema Johnston, 1916 and the largest genus of the family, Rhabdias Stiles and Hassall, 1905. DNA sequence comparisons demonstrate the presence of more than one species in the previously monotypic Pneumonema from Australian scincid lizards. The distribution of some morphological characters in the genus Rhabdias shows little consistency within the phylogenetic tree topology, in particular the apical structures widely used in rhabdiasid systematics. Our data suggest that some of the characters, while valuable for species differentiation, are not appropriate for differentiation among higher taxa and are of limited phylogenetic utility. Rhabdias is the only genus with a cosmopolitan distribution, but some of the lineages within Rhabdias are distributed on a single continent or a group of adjacent zoogeographical regions. Serpentirhabdias, Entomelas and Pneumonema show rather strict specificity to their host groups. The evolution of the Rhabdiasidae clearly included multiple host switching events among different orders and families of amphibians as well as switching between amphibians and squamatan reptiles. Only a few smaller lineages of Rhabdias demonstrate relatively strict associations with a certain group of hosts.  相似文献   

13.
The land planarian genus Choeradoplana (Plathelminthes, Tricladida) is currently integrated by 13 species. In previous works, morphological variation in its type species, Choeradoplana iheringi, was reported, but no attempt to test whether it is just a single species has been made yet. In order to disentangle the taxonomy of this species and further members of the genus, we sampled new specimens and combined morphological and molecular data and also have evaluated the performance of diverse methods of molecular species delimitation. Our data point to the presence of two cryptic species named C. iheringi, plus two new species, all hidden under the same general appearance. An in-depth morphological study of the specimens allowed detection of diagnostic morphological traits in each species, for which we also propose a molecular diagnosis. This integrative taxonomic study demonstrates once again the usefulness of molecular tools to weigh minor morphological characteristics and thus reveal the existence of species that would otherwise remain cryptic. However, under certain parameters, the molecular methods may over-split species with a high genetic structure, maybe pointing to incipient speciation. This makes critical the use of these methods combined with a comprehensive morphological approach. We also present a comprehensive phylogenetic tree including most Choeradoplana species. The tree, well supported, allows making some preliminary inferences on the evolution of the group and its historical biogeography.  相似文献   

14.
The wide distribution of the genus Ammosiphonia in the Upper Jurassic and Carboniferous of Western Siberia is established for the first time. Six haplophragmoidid species of Western Siberia are assigned to this genus. The diagnosis of the genus is emended; the taxonomic positions and scopes of the species Ammosiphonia nonioninoides (Reuss), A. beresoviensis (Bulatova), and A. sibirica (Zaspelova) are revised; two new species, A. suprajurassica sp. nov. and A. valanginica sp. nov., are described.  相似文献   

15.
Multiple geological and climatic events have created geographical or ecological barriers associated with speciation events, playing a role in biological diversification in North and Central America. Here, we evaluate the influence of the Neogene and Quaternary geological events, as well as the climatic changes in the diversification of the colubrid snake genus Rhadinaea using molecular dating and ancestral area reconstruction. A multilocus sequence dataset was generated for 37 individuals of Rhadinaea from most of the biogeographical provinces where the genus is distributed, representing 19 of the 21 currently recognized species, and two undescribed species. Our analyses show that the majority of the Rhadinaea species nest in two main clades, herein identified as “Eastern” and “Southern”. These clades probably diverged from each other in the early Miocene, and their divergence was followed by 11 divergences during the middle to late Miocene, three divergences during the Pliocene, and six divergences in the Pleistocene. The ancestral distribution of Rhadinaea was reconstructed across the Sierra Madre del Sur. Our phylogenetic analyses do not support the monophyly of Rhadinaea. The Miocene and Pliocene geomorphology, perhaps in conjunction with climate change, appears to have triggered the diversification of the genus, while the climatic changes during the Miocene probably induced the diversification of Rhadinaea in the Sierra Madre del Sur. Our analysis suggests that the uplifting of the Trans‐Mexican Volcanic Belt and Chiapan–Guatemalan highlands in this same period resulted in northward and southward colonization events. This was followed by more recent, independent colonization events in the Pliocene and Pleistocene involving the Balsas Basin, Chihuahuan Desert, Pacific Coast, Sierra Madre Occidental, Sierra Madre Oriental, Sierra Madre del Sur, Trans‐Mexican Volcanic Belt, and Veracruz provinces, probably driven by the climatic fluctuations of the time.  相似文献   

16.
The finless porpoise (genus Neophocaena) is a poorly known cetacean of great conservation concern. Within its range, from western Pacific to northwestern Indian Ocean, there are currently two species recognized (N. asiaeorientalis and N. phocaenoides), thought to be reproductively isolated since last glacial maximum, with the only sympatric overlap zone in Taiwan Strait. However, the genetic variation across the genus’ distribution has not yet been extensively studied, especially in the Indian Ocean. We performed an exhaustive review of molecular data of the finless porpoise across its range. Neighbor-net networks analyses based on two mitochondrial loci (control region/CR and cytochrome b/cyt b) suggest that finless porpoises from the Indian and Pacific Ocean constitute two distinct clades, well-defined by fixed mutations at both loci. A molecular clock analyses indicate early split (CR: 13.1 Ma, cyt b: 12.9 Ma) between these two oceanic lineages, while spatial genetic analyses further suggest that in the Pacific the divergence was primarily due to the taxon from Japanese waters rather than inter-species divergence across the Taiwan Strait. As extinction risks can be substantially underestimated if threatened species are pooled together with non-threatened, especially in the absence of long-distance migration, we suggest that the present 2-species taxonomy of the genus Neophocaena should be given further examination, with concerted sampling effort in the Western Indian Ocean. More research effort and genomic information is needed before taxonomic revisions can be considered; such further studies are strongly recommended as they may affect the current status classification of the species constituting the genus Neophocaena. Most notably, the narrow-ridged finless porpoise off Japan merits urgent conservation attention.  相似文献   

17.
Mejdalani G  Silva RS  Garcia C 《ZooKeys》2011,(160):59-71
Tacora johanni, a new species from Rondônia State, North Brazil, is described and illustrated. The new species can be recognized by the male genital features, especially the subgenital plates with the basal half distinctly expanded and with outer lateral margin round, the long and slender preapical pygofer process, and the styles with apical half strongly curved. Also, the genus is recorded for the first time from Venezuela, based on specimens of Tacora saturata Young, 1977, while the female of this species (here described in detail for the first time) shows two unusual features of the genitalia. A key to males of all known Tacora species and a map showing the known distribution of the genus are provided.  相似文献   

18.
A revision of the genus Dolichos in South Africa (Lesotho and Swaziland included) is presented. This legume genus, belonging to the bean tribe Phaseoleae, mainly has an African distribution, extending into Asia. In South Africa it is represented by nine species, two (D. sericeus and D. trilobus) of which extend into Tropical Africa. Dolichos is closely related to the genus Macrotyloma from which it can be distinguished by the short standard appendages, reticulate pollen and the generally purple flowers (standard appendages long, pollen tuberculate or spinulose and flowers yellow or orange in Macrotyloma). It also has affinities with the genera Dipogon and Lablab. The correct nomenclature, as well as complete synonymy, typification and distribution maps of all the species are provided.  相似文献   

19.
20.
The monotypic genus Hormiops Fage, 1933 is so far only known from two groups of granitic islands off the coasts of Peninsular Malaysia and Vietnam. Examination of newly collected material from both archipelagos and of the type series of Hormiops davidovi Fage, 1933 reveals previously disregarded morphological differences sufficient to assign the Malaysian specimens to a distinct species, described here as Hormiops infulcra sp. nov. An updated diagnosis of the genus, as well as a dichotomic key enabling the determination of Hormiops from its close relatives, Hormurus Thorell, 1876 and Liocheles Sundevall, 1833 are also provided. The phylogenetic position, distribution pattern, and ecology of these insular scorpions suggest that they are palaeoendemics, remnants of a previously more widely distributed lineage. A biogeographical model is proposed for the genus based on these observations and on a synthesis of palaeogeographical and palaeoenvironmental data currently available for Sundaland.  相似文献   

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