879 resultados para Teaching biological systematics and taxonomy


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The Neotropical lycaenid hairstreak genus Thepytus Robbins and its eight species are revised. Species treatments summarize nomenclature, distribution, habitat, behavior, and diagnostic traits, as well as noting why each species is considered distinct under a biological species concept. An identification key for males and a checklist are included. Beatheclus Balint & Dahners new synonym is synonymized with Thepytus, and Theppus beatrizae (Balint & Dahners) is a new combination. Other nomenclatural actions include the description of Thepytus jennifer Busby & Robbins new species. Thepytus nancyana Busby & Robbins new species, and Thepytus carmen Robbins & Duarte new species. A lectotype is designated or Thecla thyrea Hewitson, 1867, to ensure stability of this name. A phylogenetic analysis based on 22 coded morphological characters yields one equal weight most parsimonious 39-step tree. Implied weighting does not change the tree topology. Unambiguous changes in elevation optimized on the cladogram show that a montane lineage of Thepytus colonized the lowlands in at least one instance. The use of T. echelta (Hewitson) as a biological control agent for Psittacanthus (Loranthaceae) is discussed.

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We examined strains of Trypanosoma cruzi isolated from patients with acute Chagas disease that had been acquired by oral transmission in the state of Santa Catarina, Brazil (2005) and two isolates that had been obtained from a marsupial (Didelphis aurita) and a vector (Triatoma tibiamaculata). These strains were characterised through their biological behaviour and isoenzymic profiles and genotyped according to the new Taxonomy Consensus (2009) based on the discrete typing unities, that is, T. cruzi genotypes I-VI. All strains exhibited the biological behaviour of biodeme type II. In six isolates, late peaks of parasitaemia, beyond the 20th day, suggested a double infection with biodemes II + III. Isoenzymes revealed Z2 or mixed Z1 and Z2 profiles. Genotyping was performed using three polymorphic genes (cytochrome oxidase II, spliced leader intergenic region and 24Sα rRNA) and the restriction fragment length polymorphism of the kDNA minicircles. Based on these markers, all but four isolates were characterised as T. cruzi II genotypes. Four mixed populations were identified: SC90, SC93 and SC97 (T. cruzi I + T. cruzi II) and SC95 (T. cruzi I + T. cruzi VI). Comparison of the results obtained by different methods was essential for the correct identification of the mixed populations and major lineages involved indicating that characterisation by different methods can provide new insights into the relationship between phenotypic and genotypic aspects of parasite behaviour.

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Analysis of Brazilian fishers` classifications of 24 marine (Atlantic coast) and 24 freshwater (Amazon) fish species reveals that fishers from the Atlantic coast identify fish mainly through generic names (primary lexemes), while riverine Amazonian fishers typically identify them through binomials. The similarity of Amazonian fish species seems to contribute to the detailed folk taxonomy used by riverine fishers. High-ranking groups called ""relatives"" or ""cousins"" are sorted by fishers in terms of similarities of habitat, diet, and morphology and, secondarily, behavior. The general correspondence between the folk and scientific taxonomies reinforces the reality of both the supracategories used by these fishers and the biological groups as discontinuities in nature. Given the urgency of biological inventories and the lack of knowledge of high-biodiversity environments such as the Atlantic Forest and the Amazon, these results suggest that fisher knowledge and experience could contribute to scientific research.

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Idiosyncratic markers are features of genes and genomes that are so unusual that it is unlikely that they evolved more than once in a lineage of organisms. Here we explore further the potential of idiosyncratic markers and changes to typically conserved tRNA sequences for phylogenetic inference. Hard ticks were chosen as the model group because their phylogeny has been studied extensively. Fifty-eight candidate markers from hard ticks ( family Ixodidae) and 22 markers from the subfamily Rhipicephalinae sensu lato were mapped onto phylogenies of these groups. Two of the most interesting markers, features of the secondary structure of two different tRNAs, gave strong support to the hypothesis that species of the Prostriata ( Ixodes spp.) are monophyletic. Previous analyses of genes and morphology did not strongly support this relationship, instead suggesting that the Prostriata is paraphyletic with respect to the Metastriata ( the rest of the hard ticks). Parallel or convergent evolution was not found in the arrangements of mitochondrial genes in ticks nor were there any reversals to the ancestral arthropod character state. Many of the markers identified were phylogenetically informative, whereas others should be informative with study of additional taxa. Idiosyncratic markers and changes to typically conserved nucleotides in tRNAs that are phylogenetically informative were common in this data set, and thus these types of markers might be found in other organisms.

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Litargus tetraspilotus LeConte, 1856 was collected feeding on Oidium sp. (Fungi, Ascomycota, Erysiphaceae) associated with fruit trees. This is the first time L. tetraspilotus is recorded in Brazil, totaling three species of Mycetophagidae for this country. This study aims to provide a complementary description of this species based on new characters and to present information on its life cycle under laboratory conditions and fluctuation in population in the field. During the period of inventories between July 2004 and August 2006, about every fifteen days, a total of 565 specimens of L. tetraspilotus were collected, with the highest abundance found on citrus plants, with values differing significantly between the two years. The population levels differed between the seasons; spring had the greatest abundance and autumn the least. There was a significant positive correlation of L. tetraspilotus abundance with rainfall and relative humidity. Mycetophagidae, as well as other mycophagous families of Brazilian coleopterans, are barely studied, warranting further future studies of their bioecology and systematics.

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Four West Malaysian shrew populations of the genus Crocidura were investigated through their karyotype and allozyme variations, and, in part, by interfertility experiments. Two different karyotypes characterize these shrews. The first, restricted to the Cameron Highlands (Peninsular Malaysia), invariably has 2n = 40 chromosomes but a varying fundamental number (FN = 54-58). The second karyotype shows a fundamental number of 62-68 and a polymorphic chromosomal number of 2n = 38, 39 or 40, a rare event in the genus Crocidura. Thus both can be distinguished by either a low or a higher number of meta- and submetacentric elements. In heterospecific breeding experiments, mutual avoidance was observed suggesting prezygotic barriers, whereas intraspecific pairs produced 13 liters (mean 2.1 young). Furthermore, our biochemical results indicate that both karyotypes correspond to a relatively ancient separation (Nei's D = 0.354), an amount of genetic differentiation comparable to the distance separating them from the West Palearctic C. russula (D = 0.429-0.583). In contrast, conspecific island and mainland Malaysian shrews possessing the second karyotype had only one fixed allelic difference over the 35 loci surveyed. The problem of naming the two biological species remains unsolved and requires further comparative investigations.

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Sardinia is the second largest island in the Mediterranean and, together with Corsica and nearby mainland areas, one of the top biodiversity hotspots in the region. The origin of Sardinia traces back to the opening of the western Mediterranean in the late Oligocene. This geological event and the subsequent Messinian Salinity Crisis and Pleistocene glacial cycles have had a major impact on local biodiversity. The Dysdera woodlouse hunter spiders are one of the most diverse ground-dweller groups in the Mediterranean. Here we describe the first two species of this genus endemic to Sardinia: Dysdera jana sp. n. and Dysdera shardana sp. n. The two species show contrasting allopatric distribution: D. jana sp. n. is a narrow endemic while D. shardana sp. n. is distributed throughout most of the island. A multi-gene DNA sequence phylogenetic analys based on mitochondrial and nuclear genes supports the close relationships of the new species to the type species of the genus Dysdera erythrina. Age estimates reject Oligocene origin of the new Dysdera species and identify the Messinian Salinity Crises as the most plausible period for the split between Sardinian endemics and their closest relatives. Phylogeographic analysis reveals deep genetic divergences and population structure in Dysdera shardana sp. n., suggesting that restriction to gene flow probably due to environmental factors could explain local speciation events. Taxonomy, phylogeny, DNA sequencing, Mediterranean biogeography, phylogeography

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This overall focus of the thesis involves the systematics and biology of fishes of the family hemiramphidae of cochin coast.India is one of the leading fish producing nations in the world with an average annual production of 6.1 million tonnes of fish and shell fish from capture and culture fisheries in 2001 (Ayyappan and Biradar, 2002).Fisheries play a very significant role in the Indian economy by providing employment to nearly 7 million people directly or indirectly, supplying rich protein food and earning valued foreign exchange.Fishes of the family Hemiramphidae are commonly called ‘half beaks‘.In India, studies on hemiramphids commenced with the work of Day (1878,1889) who recorded thirteen species of hemiramphids from the Indian waters.The study area, which is part of Cochin coast is located between Lat.9°28’ and 10° N and Long.76° 13’ and 76° 31 E. Lying parallel to it is an estuary which is commonly called the Cochin backwaters which has a total area of about 200 sq.miles.The study area is subjected to wide variations in salinity from place to place, season and surface to bottom.The Cochin coast and the adjacent back water system of Kerala has a rich and diversified fish fauna. The hemiramphid fishes constitute a minor fishery of this area.The study on the distribution and availability of hemiramphid fishes present in the Cochin coast shows that they evince different patterns of distribution.In the present study it is noticed that fecundity has high correlation with weight than length of the fish.Histological studies revealed that the spermatogenesis in both H. (H) limbatus and H.(H) xanthopterus, consists of spermatogonia, primary spermatocytes secondary, spermatocytes, spermatids and spermatozoa whereas in the oogenesis of both the species.biological study will be useful in implementation of proper measures of conservation and management so that further devastation of the hemiramphids of Cochin Coast can be controlled.

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The thesis documents a comprehensive systematic account of Vembenad lake fishes and to study the effect of physico-chemical parameters on the distribution and abundance of fishes in the lake. This study is expected to advance the knowledge on the biological aspects of two commercially important fishes of the lake which are very desirable for brackish water fish farming. Additionally, the results of the studies on the ecology as habitat, occurrence, season and abundance of all the recorded fishes of the lake end the commercially important fish species of the lake are also incorporated. A general appraisal on the detrimental factors which are adversely affecting the fisheries resources of the lake are presented and some measures of conservation are also suggested. The results of the present study are helpful in formulating suitable schemes for management of parts of the Vembenad lake for capture and culture fisheries

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Even though Bergey '5 Manual has been recognized globally as the guide to bacterial systematics, it has to be emphasized that descriptions given to a large extent are based on studies made with temperate isolates This leads one to conclude that any attempt to identify the tropical isolates with identification keys and tables generated from this information may lead to erroneous conclusions. And there is every possibility of the existence of genotypic and phenotypic variants or even nev. species in this part ofthe aquatic ecosystem. Applications ofa polythetic scheme of classification based on the principles of Numerical Taxonomy opens up exciting avenues for bringing to light, this possibility which otherwise would have been masked by the unidirectional approach as in monothetic schemes. Another added advantage of clustering a ‘natural’ bacterial population by numerical taxonomy, is the ease by which genotypic characterization could be performed on the clusters by selecting a representative from each cluster This helps overcome the practical impossibility of analyzing all the isolates in a pani:'_lar cluster. The genotypic characteizarion would either be mole °/o G-'rC. DNA-D.\_-X hybridization, DNA-RNA hybridization or DNA fingerprinting. Considering the requirement creating a broad base in the understanding of the family Vibrionaceae associated with the larvae ofM rosenbergii, the present work was undertaken to channelize every new information generated for developing appropriate managerial measures to protect the larvae from vibriosis during the unusually prolonged larval phase.