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1.
2.
We provide a review of the systematics of Herichthys by evaluating the usefulness of several mitochondrial and nuclear genetic markers together with morphological data. The nDNA next‐generation sequencing ddRAD analysis together with the mtDNA cytochrome b gene provided well‐resolved and well‐supported phylogenies of Herichthys. On the other hand, the nDNA S7 introns have limited resolution and support and the COI barcoding analysis completely failed to recover all but one species of Herichthys as monophyletic. The COI barcoding as currently implemented is thus insufficient to distinguish clearly distinct species in the genus Herichthys that are supported by other molecular markers and by morphological characters. Based on our results, Herichthys is composed of 11 species and includes two main clades (the H. labridens and H. cyanoguttatus species groups). Herichthys bartoni is in many respects the most plesiomorphic species in the genus and has a conflicting phylogenetic position between mtDNA and nDNA markers, where the robust nDNA ddRAD data place it as a rather distant basal member of the H. labridens species group. The mtDNA of H. bartoni is on the other hand only slightly divergent from the sympatric and syntopic H. labridens, and the species thus probably have hybridized in the relatively recent past. The sympatric and syntopic Herichthys steindachneri and H. pame are supported as sister species. The Herichthys cyanoguttatus species group shows two well‐separated basal species (the northernmost H. minckleyi and the southernmost H. deppii) followed by the closely related and centrally distributed species H. cyanoguttatus, H. tepehua, H. carpintis, and H. tamasopoensis whose relationships differ between analyses and show likely hybridizations between themselves and the two basal species as suggested by conflicts between DNA analyses. Several instances of introgressions/hybridizations have also been found between the two main clades of Herichthys.  相似文献   

3.
Species of the goby genus Gnatholepis Bleeker, 1874, are common inhabitants of shallow tropical seas worldwide. In this study, mitochondrial DNA sequence (ND2 gene), from 349 Gnatholepis individuals sampled from across the South and Central Pacific and Caribbean, is used to infer phylogeny and determine species boundaries. Seven species of Gnatholepis are recognized: the Indo-Pacific G. anjerensis (Bleeker, 1851) [ G. cauerensis (Bleeker, 1853) is a synonym]; G. scapulostigma Herre, 1953; G. davaoensis Seale, 1910; G. knighti Jordan & Evermann, 1903; G. gymnocara Randall & Greenfield, 2001; G.  sp. Randall & Greenfield, 2001; and the Atlantic/Caribbean G. thompsoni Jordan, 1904. Results from the molecular phylogeny are compared with a previous morphology-based revision of the genus in order to establish which morphological characters diagnose species in correspondence with the molecular phylogeny.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 142 , 573–582.  相似文献   

4.
A new species of Litomosoides was collected from the abdominal cavity of Oligoryzomys nigripes (Rodentia: Muridae) in a semideciduous secondary rainforest of Misiones, Argentina. Litomosoides odilae n. sp. belongs to the carinii group and is characterized by the amphids displaced dorsally; buccal capsule with an anterior segment transparent and an annular asymmetrical thickening; esophagus divided, with the posterior glandular portion slightly wider than the muscular; male cloacal aperture strongly protruded; and microfilaria sheathed with an attenuated tail. The morphology of the new species, which is similar to that of L petteri, a parasite of marsupials in Brazil, suggests that host-switching events may have occurred in the diversification of this genus.  相似文献   

5.
Uganda is invoked as a metaphor for a host of arguments and insights about HIV/AIDS. However, much of what has been asserted about the country is not based on the available evidence. This paper reviews findings by epidemiologists and anthropologists, and draws on the author's experiences of researching in the country since the early 1980s. It comments on various myths about HIV/AIDS in Uganda, including myths about the origin and dissemination of the disease, about the links between HIV/AIDS and war, and about declining rates of infection. It shows that much less is known about Uganda than is commonly supposed, and it offers some alternative hypotheses for interpreting HIV prevalence and incidence data. In particular it draws attention to the importance of mechanisms for social compliance. It concludes by raising concerns about the current enthusiasm for provision of anti-retroviral drugs.  相似文献   

6.
Type material of Litomosoides hamletti Sandground, 1934 from Glossophaga soricina soricina in Brazil and L. penai Jiménez-Quirós & Arroyo, 1960 from Carollia perspicillata azteca in Costa Rica, was examined. The morphology of the spicules shows that these species belong to the carinii group. Their synonymy with L. guiterasi Pérez Vigueras, 1934, from Artibeus jamaicensis yucatanicus in Cuba, does not appear justified because they are distinct in several characters (body length, width of female, size and shape of buccal cavity and capsule, shape of right spicule). L. hamletti is a valid species; L. penai is closely related to it and is considered to be a sub-species, L. hamletti penai Jiménez-Quirós & Arroyo, 1960. The material recovered from Glossophaga spp., previously assigned to L. guiterasi by several authors, is identified as L. h. hamletti. L. guiterasi appears to be closely related to L. chandleri Esslinger, 1973; L. chitwoodi n. sp. (= Litomosoides sp. Chitwood, 1938) seems close to these species; all three are parasites of Artibeus spp.  相似文献   

7.
In order to assess the phylogenetic structure of the springtail genus Palmanura, as well as to test the monophyly of the tribe Sensillanurini (Neanuridae: Neanurinae), a data matrix of morphological (chaetotactic and other) characters of members of this group was assembled and analysed in the light of Wagner parsimony. The data matrix included all the known members of the Neotropical genus Palmanura, plus representatives of Sensillanura and Americanura. Although not all the clades obtained were highly supported by bootstrap resampling, some structures were relatively constant under different approaches. Alternative analyses (unordered and ordered character states, rescaled weighting procedure) were applied. While alternative solutions were obtained, a number of structures were shared by the results irrespective of the method used. On this basis, the results suggest that some further reassessment is required to confirm formally the monophyly of the tribe Sensillanurini. The genera Palmanura and Americanura are mutually poly/paraphyletic; we thus suggest that Palmanura should be considered as a synonym of Americanura, although some character reassessment and more varied outgroup species may be necessary before a formal generic redefinition can be proposed. Finally, a comparison of the performance of the characters under Wagner parsimony analysis indicated that differences in the characters’ retention indexes are due not to the topological (tagmal) position of the traits involved, but to character coding: the characters describing quantitative features (generally numbers of setae) generally performed worse than other types of characters under parsimony. An updated list of the known members of the Sensillanurini (Collembola: Neanuridae: Neanurinae) is presented.
© The Willi Hennig Society 2009.  相似文献   

8.
Abstract. A phylogeny for genus Agapostemon (Hymenoptera: Halictidae) is reconstructed from morphological characters, using all species, with four representatives of Agapostemonini as outgroup taxa. Parsimony analysis using 150 unordered characters resulted in eighteen equally parsimonious trees, a strict consensus of which is highly resolved for Agapostemon. Based on this analysis, Agapostemonoides Roberts & Brooks is returned to generic status, and a new subgenus is described: Notagapostemon, which includes the rhopalocerus, heterurus, atrocaeruleus, erebus, kohliellus, nasutus and intermedius groups of Moure & Hurd. Species groups are proposed for Notagapostemon and revised in A. (Agapostemon). Agapostemon cockerelli Crawford is synonymized with A. obliquus (Provancher), A. epichryseus (Morelos) with A. leunculus Vachal, A. inca Roberts with A. heterurus Cockerell, A. hispaniolicus Roberts female with A. centratus (Vachal) and A. hispaniolicus Roberts male with A. alayoi Roberts. Optimization of known behaviours suggests communal ancestry for the genus and infers the prevalence of this behaviour in Agapostemon. Optimization of geographical range suggests a Central American or Caribbean origin of Agapostemon, with one invasion of North America and multiple invasions of South America and the Caribbean. One invasion of the Caribbean suggests arrival from North America via Florida.  相似文献   

9.
The libellulid dragonfly genus Sympetrum has been recognized since 1833, but lacks any morphological synapomorphies to unite the taxon. Previous researchers have disagreed over which species belong in Sympetrum, bringing the monophyly of the genus into question. We use DNA sequence data from 6 genetic loci (16S, tRNA-valine, 12S, elongation factor 1 alpha, cytochrome oxidase subunit I, and the second internal transcribed spacer region) and 25 morphological characters (mainly genitalic) to test the monophyly of Sympetrum with Bayesian inference and maximum likelihood analyses. Under Bayesian inference, all Sympetrum species included in this study form a clade, which also contains the Hawaiian monotypic genus Nesogonia, often considered a close relative of Sympetrum. Phylogenetic analyses also reveal at least six strongly supported clades (treated as species groups) within Sympetrum, but relationships between these species groups remain unresolved or unsupported. Although the relationships between Sympetrum species groups remain unresolved, several species groups include taxa from multiple biogeographic regions/continents, and the species group sister to the rest of Sympetrum contains migratory species from the New World and Africa. This pattern suggests a complex biogeographic history in Sympetrum shaped by vicariance and dispersal. Preliminary estimates of the divergence dates of Sympetrum species groups outline a rapid radiation of the groups approximately 32-38 million years ago, possibly influenced by cooling and drying climates of the late Eocene and early Oligocene.  相似文献   

10.
Akodonema luzsarmientae n.g., n.sp. (Nemata: Metastrongyloidea) is described from the pulmonary arteries and heart from several individuals of "soft grass mouse," Akodon mollis (Rodentia: Cricetidae), collected in the region of Ancash, Peru. The new genus and species is distinguished by a reduction of the dorsal ray to 2 small widely separated papillae.  相似文献   

11.
Abstract.
  • 1 We tested switching behaviour in four species of aphidiid parasitoids, using a two-aphid experimental system consisting of second-instar nymphs of pea aphid (Acyrthosiphon pisum (Harris)) and alfalfa aphid (Macrosiphum creelii Davis) feeding on broad beans in the laboratory.
  • 2 Aphidius ervi Haliday, A.pisivorus Smith, A.smithi Sharma & Subba Rao, and Pram pequodorum Viereck showed an innate preference for pea aphid when both host species were provided in equal numbers.
  • 3 Wasps encountered both aphid species equally but differed in their acceptance of alfalfa aphid. Females of A.pisivorus and P.pequodorum accepted alfalfa aphids when few pea aphids were available, but A. smithi always concentrated attacks on pea aphid. Aphidius ervi super-parasitized an increasing proportion of pea aphids as their availability declined.
  • 4 Switching to the alfalfa aphid occurred in A.ervi and P.pequodorum (but not in A.pisivorus and A.smithi) under the condition of a 1:3 ratio of pea aphids:alfalfa aphids. Wasps did not switch when more pea aphids than alfalfa aphids were provided (3:1 ratio).
  • 5 Alfalfa aphids were more likely than pea aphids to escape from parasitoid attack.
  • 6 Switching to the most abundant host may not be adaptive in these four species of aphid parasitoids. A foraging wasp incurs a potentially higher cost in lost opportunity time when attacking (and failing to oviposit in) alfalfa aphids. In addition, alfalfa aphids may have lower host quality than pea aphids, a difference that could influence offspring fitness.
  相似文献   

12.
Zhou LW  Dai YC 《Mycologia》2012,104(1):211-222
Species of Phylloporia (Hymenochaetales, Basidiomycota) are polypores with tiny, yellowish and thick-walled basidiospores and are highly divergent in morphology. The monophyly of 35 cosmopolitan isolates of Phylloporia was strongly supported based on analysis of the nLSU rDNA gene but with exclusion of P. resupinata. Among the 19 lineages recognized in the nLSU rDNA phylogeny five new species from China, Phylloporia crataegi, P. fontanesiae, P. gutta, P. nandinae and P. oreophila, were revealed and these species are introduced with additional morphological evidence. A diagnostic key to all 23 thus far accepted species in Phylloporia is provided.  相似文献   

13.
Taxonomical classification of higher fungi remains an important challenge and can benefit from the application of molecular analysis. We propose that the ectomycorrhizal (EM) fungal taxa might include a number of cryptic species because there are few morphological characteristics useful for distinguishing among these fungi. Previously, host specificity in most EM fungi was thought to be low, but we suspect that confusion of cryptic species has led to an underestimate of fungal host specificity. We analyzed both nuclear and mitochondrial DNA sequences from Strobilomyces fungi and obtained evidence that what were previously described as four species can be grouped into 14 distinct lineages, suggesting that these lineages might be distinct biological species. Moreover, we identified host plants for Strobilomyces via nucleotide sequencing of both fungal and plant DNA from EM samples. Most lineages of Strobilomyces tested in this study were associated only with Fagaceae trees, even though Strobilomyces species were previously thought to be generalists with regard to hosts. Thus, we present an approach useful for identifying cryptic species and detecting the true host range of a set of EM fungi in natural conditions.  相似文献   

14.
The taxonomy of muriquis, the largest extant primates in the New World, is controversial. While some specialists argue for a monotypic genus (Brachyteles arachnoides), others favor a two‐species classification, splitting northern muriquis (Brachyteles hypoxanthus) from southern muriquis (B. arachnoides). This uncertainty affects how we study the differences between these highly endangered and charismatic primates, as well as the design of more effective conservation programs. To address this issue, between 2003 and 2017 we collected over 230 muriqui fecal samples across the genus’ distribution in the Brazilian Atlantic Forest, extracted DNA from these samples, and sequenced 423 base pairs of the mitochondrial DNA (mtDNA) control region. Phylogenetic and species delimitation analyses of our sequence dataset robustly support two reciprocally monophyletic groups corresponding to northern and southern muriquis separated by an average 12.7% genetic distance. The phylogeographic break between these lineages seems to be associated with the Paraíba do Sul River and coincides with the transition between the north and south Atlantic Forest biogeographic zones. Published divergence estimates from whole mitochondrial genomes and nuclear loci date the split between northern and southern muriquis to the Early Pleistocene (ca. 2.0 mya), and our new mtDNA dataset places the coalescence time for each of these two clades near the last interglacial (ca. 120–80 kya). Our results, together with both phenotypic and ecological differences, support recognizing northern and southern muriquis as sister species that should be managed as distinct evolutionarily significant units. Given that only a few thousand muriquis remain in nature, it is imperative that conservation strategies are tailored to protect both species from extinction.  相似文献   

15.
The genus Rheumatobates comprises thirty‐seven species and subspecies of New World water striders belonging to subfamily Rhagadotarsinae. Among species, males vary dramatically in the degree and nature of modifications of the antennae, three pairs of legs and abdominal and genital segments. Characters describing this modification have traditionally been used to differentiate and group species. The general assumption has been that modified species belong to one group and unmodified species to another. These two ‘species groups’ are subdivided into ‘subgroups’, but little effort has been made to resolve relationships among them. We conduct the first numerical cladistic analysis of Rheumatobates using a data set comprised of 102 characters, primarily describing modification of male external morphology. To address concerns about the inclusion of characters to be optimized on the phylogeny, characters describing modification of antennae and hind legs were included and then excluded in separate analyses. A preferred phylogeny was chosen from the four equally parsimonious cladograms found after successive reweighting of characters. There was good resolution at all levels of the phylogeny. Most of the major clades and terminal relationships were moderately to strongly supported, whereas the basal relationships were less well supported. The general assumption that unmodified and modified species form two monophyletic groups was not supported. However, traditionally recognized ‘subgroups’ within the modified species group were largely upheld. The analysis also suggested several major clades and relationships among these clades that were not previously recognized. The exclusion of characters describing modification of antennae and hind legs did not change the resolved major clades of the reconstructed phylogeny.  相似文献   

16.
The expression and secretion of Bacillus amyloliquefaciens alpha-amylase was studied in yeast Saccharomyces cerevisiae. The Bacillus promoter was removed by BAL 31 digestion and three forms of the alpha-amylase gene were constructed: the Bacillus signal sequence was either complete (YEp alpha a1), partial (YEp alpha a2) or missing (YEp alpha a3). Secretion of alpha-amylase into the culture medium was obtained with the complete signal sequence only. The secreted alpha-amylase was glycosylated and its signal peptide was apparently processed. The glycosylated alpha-amylase remained active. The enzyme produced by the other constructions was not glycosylated and thus probably remained in the cytoplasm.  相似文献   

17.
Based on 28 taxa, including six species of Phylloporia, and respectively one representative of 17 genera of the Hymenochaetales, a phylogenetic analysis of a region of the large subunit of the nuclear encoded ribosomal DNA was performed. Molecular sequence data as well as morphological and anatomical features show the genus to be monophyletic. Next related to Phylloporia is Fulvifomes. The phylogenetic relationships of Phylloporia are discussed. In addition the genus Phylloporia is monographed; 12 species are accepted and described with a key.  相似文献   

18.
A new species of Litomosoides is described from sigmodontine murids occurring in the rain forests of Misiones, Argentina. Litomosoides anguyai n. sp., a parasite of the abdominal cavity of Oxymycterus misionalis, belongs to the sigmodontis group and is closely related to L. legerae and L. oxymycteri. The new species is differentiated by the salient amphids, an asymmetrical annular thickening of the buccal capsule, by the arrangement of the head and tail papillae, and the shape and size of the microfilaria.  相似文献   

19.
The parrot genus Prioniturus occurs in the oceanic Philippines, Palawan and Wallacea, a geologically dynamic region with a complex history of land and sea. The described taxa of Prioniturus have been variously placed in different assemblages, and different numbers of species have been recognized. However, a phylogenetic framework is so far lacking. This would be the prerequisite to reconstructing dispersal and colonization patterns of Prioniturus across and within Wallacea and the Philippines. Following our robustly supported phylogenetic hypothesis based on two mitochondrial genes, we propose to treat Prioniturus mindorensis comb. nov. as well as Prioniturus montanus and Prioniturus waterstradti as separate species. In Prioniturus discurus discurus and Prioniturus discurus whiteheadi, further studies using additional data and specimens are necessary to clarify their taxonomic status. This result is congruent with other studies demonstrating that alpha diversity of the Philippine avifauna is strongly underestimated. According to our biogeographic reconstruction, Prioniturus has diversified by a complex combination of colonization of islands and subsequent divergence in allopatry among and within island groups. Dispersal between Sulawesi/Wallacea and the Philippines occurred twice and documents a rare case of faunal exchange between these two regions.  相似文献   

20.
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