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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Contribuição ao conhecimento da oesteologia Pachypops adspersus (Steindachner): complexos cefálicos e caudal

Souza, Ivani Callado de January 1980 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-09-13T23:59:58Z No. of bitstreams: 1 200909.pdf: 2799695 bytes, checksum: 3f7db4b7ea0866099b1da9bd33e167a6 (MD5) / Made available in DSpace on 2017-09-13T23:59:58Z (GMT). No. of bitstreams: 1 200909.pdf: 2799695 bytes, checksum: 3f7db4b7ea0866099b1da9bd33e167a6 (MD5) Previous issue date: 1980 / Com base em um grupo de vinte exemplares de Pachypops adspersus (Steindachner), indivíduos jovens e adultos, é analisada a osteologia de seu esqueleto cefálico e complexo caudal, considerando a importância desses componentes estruturais nas interpretações taxionômicas, filogenêtica e evolutiva dos TELEOSTEI. O material observado procede do Lago Dom Helvécio, situado na área preservada do Parque Florestal do Vale do Rio Doce, no Estado de Minas Gerais. O estudo em questão inclui as estruturas do neurocrânio e do esplancnocrânio. Sobre o complexo caudal aborda-se a morfologia da nadadeira caudal e os elementos da coluna vertebral responsáveis pela sustentação da mesma. Com os resultados obtidos discute-se ainda a posição filogenética da espécie estudada entre os PERCOIDEI. / We have analised here the osteology of the cephalic bones and tail complex of young and adult fishes of the Pachypops adspersus (Steindachner) class, twenty of which were available, having in view the importance of these structural components on taxinomic, philogenetic and evolutive interpretation of the TELEOSTEI. The studied samples proceed from Dom Helvécio Lake, situated in the Parque Florestal do Vale do Rio Doce preserved area, in Minas Gerais State. The present study includes the neurocraneo and splancnocraneo. As for the tail complex, we presented the morphology of the tail fin and the spinal column elements, responsible for it. With the obtained results, it is still discussed the philogenetic position of the species studied among the PERCOIDEI.
12

The taxonomy, life-history and population dynamics of blacktail, Diplodus Capensis (Perciformes: Sparidae), in southern Angola

Richardson, Timothy John January 2010 (has links)
The blacktail, Diplodus capensis, is an inshore sparid fish distributed from Mozambique to Angola. This species forms an important component of coastal fisheries within its distribution, one being the subsistence handline fishery in southern Angola. With this fishery being critically important to the livelihoods of local communities, a biological study and stock assessment was conducted to provide information for the management of this species in southern Angola. However, with molecular evidence suggesting that the Benguela current may have separated the southern African populations of many inshore fish species over two million years ago, a morphological, taxonomic analysis was considered necessary to first investigate whether there was evidence for allopatry in this species. A total of 46 morphometric measurements and 18 counts were carried out on specimens collected from various locations in southern Angola and South Africa. Results were analysed using multi-dimensional scaling (MDS) and the significance of clusters was tested using analysis of similarities (ANOSIM). Biological samples of D. capensis were collected monthly from an unexploited area from April 2008 to March 2009. Additional biological samples were collected from the subsistence fishers in an exploited area during May, June and December 2009. Standard biological laboratory techniques were employed for the lifehistory comparison between the exploited and unexploited area. A per-recruit analysis was conducted using the life-history parameters from both areas in order to assess the current status of the subsistence fishery and to investigate the potential short-falls of the per-recruit assessment approach. The morphometric comparison showed that there was not sufficient evidence for speciation between the southern Angolan and South African populations of D. capensis. There was, however, sufficient morphological evidence to suggest that these populations are separate stocks. This indicated that the existing reference points on which the management of the South African population is based are unsuitable for the Angolan population. Diplodus capensis in southern Angola is omnivorous, feeding predominantly on algae, barnacles and mussels. An ontogenetic shift from algae to barnacles and mussels was correlated with allometric growth patterns in their feeding apparatus. This species is a rudimentary hermaphrodite in southern Angola with peak spawning in June and July. The overall sex ratio (M: F) was 1: 4.7 in the unexploited area and 50% maturity was attained at 149.5mm FL and five years. Diplodus capensis in southern Angola exhibits very slow growth with the maximum age observed being 31 years (validated using mark recapture of chemically injected fish). Females [L(t) = 419.5(1-e⁻°·°⁴⁵⁽t⁻³·⁴ ⁾)] grew significantly faster (LRT, p < 0.05) than males [L(t) = 297.4(1-e⁻°·°⁷⁷⁽t⁻²·⁷⁾)], and females dominated the larger size classes and older age classes. In the exploited area, the length and age frequencies were severely truncated, the maximum observed age was greatly reduced (17 years) and the sex ratio was less female biased at 1: 2.2. Although there was no evidence for a physiological response to exploitation through alterations in growth or size/age at sexual maturity between the two areas, there was an increase in the proportion of small females in the exploited area, which may have been a compensatory response for the loss of large females. A combination of an underestimate of longevity, different estimates of the Von Bertalanffy growth parameters and overestimates of the natural mortality rate in the exploited population resulted in a 92% underestimate of the pristine spawner biomass-per-recruit (SBR) value. An assessment based on the actual pristine SBR estimate from the unexploited area revealed that the subsistence fishery had actually reduced D. capensis to 20% of its pristine SBR levels and highlighted the value of pre-exploitation life-history information for the application of per-recruit models. This study has shown that D. capensis in southern Angola displays life-history characteristics that render it susceptible to overexploitation, even at low levels of fishing pressure. The current lack of infrastructure and enforcement capacity in the fisheries department of Angola renders traditional linefish regulatory tools, such as size limits, bag limits and closed seasons, inappropriate. Therefore, suitably designed marine protected areas are recommended as the best management option for this species.
13

Aspectos cariogen?micos em esp?cies marinhas de Haemulidae (Perciformes) e Labridae (Labriformes): uma perspectiva evolutiva

Motta Neto, Cl?vis Coutinho da 29 September 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-21T13:09:14Z No. of bitstreams: 1 ClovisCoutinhoDaMottaNeto_TESE.pdf: 24405489 bytes, checksum: f4b763bedf2b803da39f795bc3d80ff3 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-23T15:58:48Z (GMT) No. of bitstreams: 1 ClovisCoutinhoDaMottaNeto_TESE.pdf: 24405489 bytes, checksum: f4b763bedf2b803da39f795bc3d80ff3 (MD5) / Made available in DSpace on 2018-03-23T15:58:48Z (GMT). No. of bitstreams: 1 ClovisCoutinhoDaMottaNeto_TESE.pdf: 24405489 bytes, checksum: f4b763bedf2b803da39f795bc3d80ff3 (MD5) Previous issue date: 2017-09-29 / O Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A S?rie Percomorpha ? maior divis?o entre os vertebrados, constituindo o maior e mais derivado clado de peixes tele?steos. Dentre suas Ordens, Perciformes e Labriformes constituem modelos adequados ? investiga??o do conservadorismo e diversifica??o cromoss?mica. Em Perciformes o conservadorismo cromoss?mico ? representado por cari?tipos basais com 2n=48 acroc?ntricos, extensivamente compartilhados por uma parcela consider?vel de esp?cies. As causas e extens?o do conservadorismo cariot?pico em v?rias fam?lias desta Ordem n?o s?o inteiramente claras. Diante da diversidade de esp?cies em Labriformes, aspectos mais detalhados de sua evolu??o cariot?pica ou mesmo status taxon?mico de algumas esp?cies merecem particular aten??o. Com vistas a contribuir com novas informa??es sobre essas quest?es foram implementadas an?lises cromoss?micas convencionais (colora??o convencional com Giemsa, bandamento C e Ag-RONs, fluocrocromos base-espec?ficos) e citomoleculares (hibridiza??o in situ com sondas DNAr 18S, DNAr 5S). Oito esp?cies dos g?neros Anisotremus e Haemulon da fam?lia Haemulidae (Perciformes) foram analisadas, incluindo amostras de diferentes ?reas do Atl?ntico, como modelo de evolu??o conservativa. Em 2 esp?cies do g?nero Bodianus da fam?lia Labridae (Labriformes), foram analisados tamb?m aspectos da evolu??o de sequ?ncias repetitivas particulares (DNAr 18S, DNAr 5S, Alu e Tol2) nos cromossomos por hibridiza??o com 5 metilcitosina (5mC). Adicionalmente, foram realizadas compara??es filogen?ticas, utilizando sequ?ncias de DNA mitocondrial (COI e 16S) e nuclear (Rodopsina) para verificar o status taxon?mico da esp?cie Bodianus insularis, end?mica das ilhas Meso-Atl?nticas. Todas as esp?cies de Haemulidae apresentaram 2n=48a, s?tios Ag-RONs simples e heterocromatina centrom?rica reduzida, al?m de consider?vel compartilhamento de s?tios de DNAr 5S e 18S, confirmando a ocorr?ncia de estase cariot?pica na fam?lia. Os padr?es cariot?picos das popula??es de A. virginicus e H. chrysargyreum entre o Caribe e Atl?ntico Sul n?o revelaram varia??es cromoss?micas decorrentes da barreira dos des?gues dos rios Amazonas/Orinoco. Em Bodianus, as an?lises identificaram uma not?vel regi?o descondensada em um par cromoss?mico subteloc?ntrico, denominada regi?o BOD. Entre suas caracter?sticas constitutivas e funcionais particulares, se mostram DAPI-, argentof?lica (Ag+), marcantemente hipometilada e saturada de elementos transpon?veis, sugerindo que a participa??o destes elementos m?veis pode ter contribu?do para sua g?nese e din?mica epigen?tica complexa. Quanto a esp?cie end?mica B. insularis, sua diverg?ncia gen?tica ? muito inferior ? apresentada por esp?cies diferenciadas sugerindo que embora represente um grupo geograficamente isolado, constitua uma sinon?mia de B. pulchellus. A diverg?ncia nos ritmos de diversifica??o cariot?pica entre Haemulidae e Labridae ? aqui discutida ? luz de caracter?sticas cariot?picas intr?nsecas que podem favorecer o tamponamento e a fixa??o de mudan?as cromoss?micas e aspectos biol?gicos das esp?cies que contribuem para as condi??es particulares de evolu??o cariot?pica desses dois grupos de peixes marinhos. / Percomorpha series is the largest division among vertebrates, constituting the largest and most derived clade of teleostean fishes. Among its Orders, Perciformes and Labriformes constitue adequated models for the investigation of conservatism and chromosomal diversification. In Perciformes the chromosomal conservatism is represented by basal karyotypes with 2n = 48 acrocentric, extensively shared by a considerable portion of species. The causes and extent of the karyotypic conservatism in various families of this Order are not entirely clear. In front of the diversity of species in Labriformes, more detailed aspects of its karyotype evolution or even the taxonomic status of some species deserve particular attention. In order to contribute with new information on these issues, it was implemented conventional chromosome analysis (conventional staining with Giemsa, C-banding and Ag- NORs, base-specific fluochromes) and cytomolecular (in situ hybridization with 18S rDNA, 5S rDNA) probes were implemented. Eight species of the genera Anisotremus and Haemulon of the family Haemulidae (Perciformes) were analyzed, including samples from different areas of the Atlantic, as a model of conservative evolution. In 2 species of the Bodianus genus Labridae (Labriformes), it was also analyzed aspects of the evolution of particular repetitive sequences (DNAr 18S, DNAr 5S, Alu and Tol2) in the chromosomes by hybridization with 5 methylcytosine (5mC). Additionally, phylogenetic comparisons were performed using mitochondrial (COI and 16S) and nuclear (Rhodopsin) DNA sequences to verify the taxonomic status of the Bodianus insularis species, endemic to the Meso-Atlantic islands. All Haemulidae species presented 2n = 48a, single Ag-NORs sites and reduced centromeric heterochromatin, besides considerable sharing of rDNA 5S and 18S sites, confirming the occurrence of karyotype stasis in the family. The karyotypic patterns of the populations of A. virginicus and H. chrysargyreum between the Caribbean and the South Atlantic did not reveal chromosomal variations due to the barrier of the discharges of the Amazonas / Orinoco rivers. In Bodianus, the analyzes identified a remarkable decondensed region in a subtelocentric chromosomal pair, denominated BOD region. Among its particular constitutive and functional characteristics, it is DAPI-, Argentof?lica (Ag +), markedly hypomethylated and saturated with transposable elements, suggesting that the participation of these mobile elements may have contributed to its genesis and complex epigenetic dynamics. In relation to the endemic species B. insularis its genetic divergence is much inferior to that presented by differentiated species suggesting that although it represents a geographically isolated group, it constitutes a synonym of B. pulchellus. The divergence in the rates of karyotype diversification between Haemulidae and Labridae is discussed here in the light of intrinsic karyotype characteristics that may favor the buffering and the fixation of chromosomal changes and biological aspects of the species that contributes to particular conditions of karyotype evolution of these two groups of marine fish.

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