957 resultados para 270501 Animal Systematics, Taxonomy and Phylogeny


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Recent molecular and morphological studies of the genera Rhipicephalus Koch, 1844 and Boophilus Curtice, 1891 revealed that the five species of Boophilus make the genus Rhipicephalus paraphyletic. Thus, Rhipicephalus Koch, 1844 is not a monophyletic ( natural) lineage and some species of Rhipicephalus are more closely related to the species of Boophilus than to other species of Rhipicephalus. Here, we revise these genera: Boophilus is synonymised with Rhipicephalus, and Rhipicephalus ( sensu lato) ( including Boophilus) is redefined. By synonymising Boophilus with Rhipicephalus, we have changed the nomenclature so that it reflects our understanding of the phylogeny of these ticks. Boophilus is retained as a subgenus of Rhipicephalus, so the synonymy of Boophilus with Rhipicephalus does not result in the loss of the name Boophilus. In addition, Rhipicephalus is a well- known genus and the change proposed is simple - all five species of Boophilus become members of Rhipicephalus ( Boophilus).

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Previously, two species of Myrmozercon (= Myrmonyssus) have been described from ground-nesting Australian ants in the genus Iridiomyrmex. Herein a new species, Myrmozercon iainkayi, infesting workers and alate adults of a leaf-nesting species of Polyrachis ant is described. The new species has a number of unusual or unique characters, including coxal hypertrichy (6-6-6-4 for legs I-IV, respectively), and based on the structure of its mouthparts, appears to be a haemolymph-feeding parasite.

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The mite family Stigmaeidae (Acari:Prostigmata) is of considerable importance in biological control, but its genera are often poorly defined and have never been subjected to cladistic analysis. Herein, we report the stigmaeid genus Ledermuelleriopsis Willmann from Australia for the first time, present a preliminary phylogenetic analysis that demonstrates that Eustigmaeus Berlese and Ledermuelleriopsis Willman are distinct, review the genus at the world level, and provide diagnostic characters of the adult females for each of the 21 known species. We also catalogue habitats, distributions and localities of holotypes. Four new species from Australia are described and illustrated: L. parvilla, sp. nov. from old dune sand, L. barbellata, sp. nov. from wet-sandy heath litter, and L. pustulosa, sp. nov. and L. claviseta, sp. nov. from dry eucalypt forest litter. A key to adult females of all known Ledermuelleriopsis species is provided. The Australian species and L. incisa Wood from New Zealand can be separated from all other members of the genus by a synapomorphy: the reduction of the number of setae on the aggenital shield to one pair. Results of a preliminary morphological cladistic analysis for those stigmaeid genera in which the larvae and adults of both sexes are known, indicate that Ledermuelleriopsis is basal to a clade containing Cheylostigmaeus Willman and Eustigmaeus.

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The founding of new populations by small numbers of colonists has been considered a potentially important mechanism promoting evolutionary change in island populations. Colonizing species, such as members of the avian species complex Zosterops lateralis, have been used to support this idea. A large amount of background information on recent colonization history is available for one Zosterops subspecies, Z. lateralis lateralis, providing the opportunity to reconstruct the population dynamics of its colonization sequence. We used a Bayesian approach to combine historical and demographic information available on Z. l. lateralis with genotypic data from six microsatellite loci, and a rejection algorithm to make simultaneous inferences on the demographic parameters describing the recent colonization history of this subspecies in four southwest Pacific islands. Demographic models assuming mutation–drift equilibrium or a large number of founders were better supported than models assuming founder events for three of four recently colonized island populations. Posterior distributions of demographic parameters supported (i) a large stable effective population size of several thousands individuals with point estimates around 4000–5000; (ii) a founder event of very low intensity with a large effective number of founders around 150–200 individuals for each island in three of four islands, suggesting the colonization of those islands by one flock of large size or several flocks of average size; and (iii) a founder event of higher intensity on Norfolk Island with an effective number of founders around 20 individuals, suggesting colonization by a single flock of moderate size. Our inferences on demographic parameters, especially those on the number of founders, were relatively insensitive to the precise choice of prior distributions for microsatellite mutation processes and demographic parameters, suggesting that our analysis provides a robust description of the recent colonization history of the subspecies.

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Known Early-Middle Miocene terrestrial strata of southern New Zealand are represented by alluvial plain and lacustrine sediments. A vertebrate fauna including fish, ducks, and crocodiles populated Lake Manuherikia, with abundant mussels, gastropods, and stromatolites occupying the near-shore areas of the lake. A diverse vegetation covered the surrounding broad fluvial plains that extended to the coastal margins. Initially this was largely rainforest, which varied according to habitat and to changing climate. In particular, the climate and ecology appear to have fluctuated across the two major thresholds of fire/no-fire and of peat accumulation and no-peat. A major climate change, possibly the sharp global deterioration in conditions at about 14 Ma, profoundly changed the vegetation. Rainforest continuity fragmented, and herblands became widespread. Leaf fossils effectively disappear from the record at this time.

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A new thelastomatid, Aoruroides queenslandensis, is described from two native Australian cockroaches, Panesthia tryoni tryoni Shaw and P. cribrata Saussure, from sub-tropical rainforest in south-eastern Queensland. Species of Aoruroides Travassos & Kloss, 1958 have previously been reported from cockroaches found in Brazil and the Philippines, but A. queenslandensis n. sp. is the first species of this genus found in Australia. The new species differs from the other members of Aoruroides principally in the position of the nerve-ring and egg morphology.

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The ischnacanthid acanthodian Grenfellacanthus zerinae gen. et sp. nov. is described on the basis of two large jaw bones from the Late Devonian (late Famennian) Hunter Formation, near Grenfell, N.S.W. The new species is the youngest known ischnacanthid, and the largest ischnacanthid from Gondwana. As for many ischnacanthids, the structure of the jaws and teeth indicate that Grenfellacanthus was probably an ambush predator.

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Competition over access to food has led to the evolution of a variety of exaggerated visual and vocal displays in altricial nestling birds. Precocial chicks that are fed by their parents also vary widely in appearance ranging from those with inconspicuous coloration to those with brightly colored bills, fleshy parts, and plumes. These ornaments are lost by the end of the period of parental dependence, suggesting they function in competition over parental care. We use a comparative approach to evaluate which ecological or life-history variables may have favored the evolution of conspicuous ornamentation in precocial chicks. We compiled data on chick morphology, ecology, and social organization of species in the Family Rallidae, a group with highly variable downy chicks. Chick ornamentation in the form of brightly colored bills, fleshy patches, or plumes is observed in 36 of 97 species for which downy chicks are described. Phylogenetic reconstructions suggest that nonornamentation is the ancestral state. Chick ornamentation has evolved multiple times within the Rallidae and is significantly associated with large clutch sizes and polygamous mating systems. Chick ornamentation was also weakly associated with adult ornamentation and adult dimorphism. We argue that these results support the hypothesis that lineages with higher levels of sibling competition are more likely to evolve ornamented chicks.

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Glaphyromorphus clandestinus, sp. nov., is described from granite-slab habitat on Mt Elliot, north-eastern Queensland. This species can be distinguished from its congeners by a combination of the following characters: large size (SVL 72 mm), adpressed limbs of adult separated by noticeably more than the length of the forelimb, 26 mid-body scale rows, and flanks patterned with dark flecks forming a series of longitudinal lines. The distribution, habitat preferences and habits of this species are poorly known. Currently G. clandestinus is known from a single locality where individuals have been found in an exposed area of exfoliating granite, set in a mosaic of rainforest and eucalyptus woodland. The discovery of this species brings to three the number of vertebrate species known to be endemic to Mt Elliot and highlights the evolutionary significance of this southerly outlier to the mountainous rainforest of the Wet Tropics.

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A new dracunculoid genus and species, Moravecia australiensis, is described from gill-filaments of the green porcupine fish Tragulichthys jaculiferus (Cuvier) (Tetraodontiformes: Diodontidae) from Moreton Bay, Queensland, Australia. Abundant mobile larvae and a few adult males with females occurred in the gill-filament between the epithelial basement membrane and efferent artery. Gills of all 69 fish examined contained larvae. Eleven harboured adult nematodes of a previously undescribed species belonging to the family Guyanemidae. The new species is placed within a newly proposed genus because it differs from the four existing genera in the family in possessing fine cuticular transverse striations, two forward protruding cephalic elevations, a circumoral elevation, a small triangular mouth surrounded by six cephalic papillae arranged in two lateral clusters of three each and a pair of large lateral amphids. Males have two pairs of pedunculate caudal papillae supporting the caudal alae. A key to the genera of the Guyanemidae is presented.

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There are two major groups of ticks: soft ticks and hard ticks. The hard ticks comprise the prostriate ticks and the metastriate ticks. The mitochondrial (mt) genomes of one species of prostriate tick and two species of metastriate ticks had been sequenced prior to our study. The prostriate tick has the ancestral arrangement of mt genes of arthropods, whereas the two metastriate ticks have rearrangements of eight genes and duplicate control regions. However, the arrangement of genes in the mt genomes of soft ticks had not been studied. We sequenced the mt genomes of two species of soft ticks, Carios capensis and Ornithodoros moubata, and a metastriate tick, Haemaphysalis flava. We found that the soft ticks have the ancestral arrangement of mt genes of arthropods, whereas the metastriate tick, H. flava, shares the rearrangements of mt genes and duplicate control regions with the other two metastriate ticks that have previously been studied. Our study indicates that gene rearrangements and duplicate control regions in mt genomes occurred once in the most recent common ancestor of metastriate ticks, whereas the ancestral arrangement of arthropods has remained unchanged for over 400 million years in the lineages leading to the soft ticks and the prostriate ticks.