9 resultados para lamniformes


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This paper reports the first well-documented specimen of the goblin shark, Mitsukurina owstoni in the south-western Atlantic, based on a mature male measuring 3152 mm total length, caught on 27 November 2008 off the Rio de Janeiro coast, south-east Brazil.

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This paper reports the first well-documented specimen of the goblin shark, Mitsukurina owstoni in the south-western Atlantic, based on a mature male measuring 3152 mm total length, caught on 27 November 2008 off the Rio de Janeiro coast, south-east Brazil.

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Molecular-based approaches for shark species identification have been driven largely by issues specific to the fishery. In an effort to establish a more comprehensive identification data set, we investigated DNA sequence variation of a 1.4-kb region from the mitochondrial genome covering partial sequences from the 12S rDNA, 16S rDNA, and the complete valine tRNA from 35 shark species from the Atlantic fishery. Generally, within-species variability was low in relation to interspecific divergence because species haloptypes formed monophyletic groups. Phylogenetic analyses resolved ordinal relationships among Carcharhiniformes and Lamniformes, and revealed support for the families Sphyrnidae and Triakidae (within Carcharhiniformes) and Lamnidae and Alopidae (within Lamniformes). The combination of limited intraspecific variability and sufficient between-species divergence indicates that this locus is suitable for species identification.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Eight embryonic thresher sharks Alopias vulpinus (53.9-124 cm total length) were collected from two females caught by commercial longline off southern Brazil in September and November 2004. Morphometric measurements are provided. (c) 2006 the Authors.

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Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

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The bigeye thresher, Alopias supercilious, is commonly caught as bycatch in pelagic longline fisheries targeting swordfish. Little information is yet available on the biology of this species, however. As part of an ongoing study, observers sent aboard fishing vessels have been collecting set of information that includes samples of vertebrae, with the aim of investigating age and growth of A. supercilious. A total of 117 specimens were sampled between September 2008 and October 2009 in the tropical northeastern Atlantic, with specimens ranging from 101 to 242 cm fork length (FL) (176 to 407 cm total length). The A. supercilious vertebrae were generally difficult to read, mainly because they were poorly calcified, which is typical of Lamniformes sharks. Preliminary trials were carried out to determine the most efficient band enhancement technique for this species, in which crystal violet section staining was found to be the best methodology. Estimated ages in this sample ranged from 2 to 22 years for females and 1 to 17 years for males. A version of the von Bertalanffy growth model (VBGF) re-parameterised to estimate L(0), and a modified VBGF using a fixed L(0) were fitted to the data. The Akaike information criterion (AIC) was used to compare these models. The VBGF produced the best results, with the following parameters: L(inf) = 293 cm FL, k = 0.06 y(-1) and L(0) = 111 cm FL for females; L(inf) = 206 cm FL, k = 0.18 y(-1) and L(0) = 93 cm FL for males. The estimated growth coefficients confirm that A. supercilious is a slow-growing species, highlighting its vulnerability to fishing pressure. It is therefore urgent to carry out more biological research to inform fishery managers more adequately and address conservation issues.

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O presente trabalho consiste na apresentação da diversidade de seláceos do Farol das Lagostas pertencente à Bacia do Cuanza. Os condrichthyes são componentes comuns da fauna aquática desde o Paleozoico. No entanto, devido à natureza cartilaginosa do esqueleto, o registo paleontológico dos mesmos restringe-se, basicamente, às partes mineralizadas como dentes, dentículos dérmicos e espinhas cefálicas O lugar Farol das Lagostas contém uma fauna de seláceos relativamente rica e variada, representada neste estudo por cerca de 1.000 dentes isolados, além de outras peças esqueléticas. Foram identificados e descritos quarenta e quatro taxa, pertencentes às seguintes ordens: Hexanchiformes, Squaliformes, Pristiophoriformes, Squatiniformes, Lamniformes, Carcharhiniformes, Rajiformes e Myliobatiformes. Trata-se de uma diversidade faunística cuja maioria dos géneros possui representantes atuais. Os Carcharhiniformes representam 53% dos taxa identificados. Estão representadas as famílias Scyliorhinidae, Triakidae, Hemigaleidae, Carcharhinidae e Sphyrnidae, com 18 espécies. Verifica-se a presença de formas bentónicas e nectónicas que indicam condições térmicas moderadas, quentes e tropicais a temperadas, que habitam frequentemente zonas costeiras. A relação faunística identificada corresponde a uma zona litoral. Ora, considerando o conjunto de dados em face da presença de fauna pelágica e dos grandes predadores, especialmente Isurus hastalis e Carcharocles megalodon, podemos admitir que existisse então um Golfo relativamente largo de uma faixa Atlântica aberta (Antunes & Balbino, 2004); ABSTRACT: Selachians from Farol the Lagostas (Cuanza Basin, Angola) The present work consists of the presentation of diversity of selachians from Farol das Lagostas, which belongs to the Cuanza Basin. The condrichthyes are a part of aquatic fauna since the Paleozoic. However, due to the nature of the cartilaginous skeleton, the paleontological registration of the same ones is restricted to mineralized parts like teeth, dermal denticles and cephalic spines. The of formation, Farol das Lagostas has a fauna of selachian relatively rich and diverse, represented in this study for around 1.000 isolated teeth, and other skeletal parts. Forty four taxa were described and identified, belonging to the following orders: Hexanchiformes, Squaliformes, Pristiophoriformes, Squatiniformes, Lamniformes, Carcharhiniformes, Rajiformes e Myliobatiformes. It’s a faunal diversity whose most genera have current representatives. The Carcharhiniformes represente 53% of the identified taxa. The represented families are Scyliorhinidae, Triakidae, Hemigaleidae, Carcharhinidae e Sphyrnidae, with 18 species. There is presence of benthic and nektonic forms that indicate moderate thermal conditions, the temperate and tropical hot, often inhabit coastal areas. The identified faunal relation corresponds to a coastal zone. So, considering the data set, due to the presence of pelagic fauna and large predators, especially Isurus hastalis e Carcharocles megalodon, we can admit that then there was a relatively large Gulf of open Atlantic range (Antunes & Balbino, 2004).

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O afloramento de Brielas, costa de Caparica (Miocénico Médio) apresenta uma elevada riqueza especifica representada neste estudo por 671 dentes isolados, 11 dentículos dérmicos e 4 fragmentos de aguilhão. Foram identificados e descritos quarenta seis taxa pertencentes as seguintes ordens: Carcharhiniformes,Myliobatiformes, Hexanchiformes, Lamniformes, Rajiformes, Squatiniformes e Torpediniformes. Trata-se de uma fauna cuja maioria dos géneros possuem representantes actuais e onde se encontram, inclusivamente,algumas espécies que existem actualmente no território marítimo português. Descreve-se pela primeira vez no registo f6ssil português Torpedo torpedo, e o género Mustelus é descrito em idade mais antiga que a da primeira referencia deste género em Portugal. Verifica-se a presença de formas bentónicas e nectónicas de águas quentes tropicais a temperadas, que habitariam frequentemente zonas costeiras; é de notar a presença de certas formas em detrimento de outras, reforçando as conclusões de investigadores anteriores.