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1.
Science ; 383(6687): 1135-1141, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38452078

RESUMO

The deep ocean is the last natural biodiversity refuge from the reach of human activities. Deepwater sharks and rays are among the most sensitive marine vertebrates to overexploitation. One-third of threatened deepwater sharks are targeted, and half the species targeted for the international liver-oil trade are threatened with extinction. Steep population declines cannot be easily reversed owing to long generation lengths, low recovery potentials, and the near absence of management. Depth and spatial limits to fishing activity could improve conservation when implemented alongside catch regulations, bycatch mitigation, and international trade regulation. Deepwater sharks and rays require immediate trade and fishing regulations to prevent irreversible defaunation and promote recovery of this threatened megafauna group.


Assuntos
Conservação dos Recursos Naturais , Extinção Biológica , Caça , Tubarões , Rajidae , Animais , Humanos , Internacionalidade , Carne , Óleos de Peixe , Biodiversidade , Oceanos e Mares , Risco
2.
Life (Basel) ; 11(7)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206388

RESUMO

Conservation and long-term management plans of marine species need to be based upon the universally recognized key-feature of species identity. This important assignment is particularly challenging in skates (Rajiformes) in which the phenotypic similarity between some taxa and the individual variability in others, hampers accurate species identification. Here, 432 individual skate samples collected from four major ocean areas of the Atlantic were barcoded and taxonomically analysed. A BOLD project ELASMO ATL was implemented with the aim of establishing a new fully available and well curated barcode library containing both biological and molecular information. The evolutionary histories of the 38 skate taxa were estimated with two concatenated mitochondrial markers (COI and NADH2) through Maximum Likelihood and Bayesian inference. New evolutionary lineages within the genus Raja were discovered off Angola, where paleogeographic history coupled with oceanographic discontinuities could have contributed to the establishment of isolated refugia, playing a fundamental role among skates' speciation events. These data successfully resolved many taxonomic ambiguities, identified cryptic diversity within valid species and demonstrated a highly cohesive monophyletic clustering among the order, laying the background for further inference of evolutionary patterns suitable for addressing management and conservation issues.

3.
Zootaxa ; 4691(3): zootaxa.4691.3.3, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31719391

RESUMO

A new species of the genus Leucoraja is described from off Kenya in the Western Indian Ocean (WIO). The new species was collected during a survey of the R/V Fridtiof Nansen. Leucoraja elaineae sp. n. is the third species in the genus found to occur in the WIO, and the only species in the genus Leucoraja known exclusively from this region. Its closest geographic congener L. wallacei, occurring from Namibia to southern Mozambique, can be separated by a combination of morphological and meristic characters including an elongated, pronounced snout (L. elaineae sp. n.) vs a short, blunt snout (L. wallacei), higher predorsal vertebral (107 vs 64-74) and pectoral fin radial counts (77 vs 61-64), a dorsal surface pattern consisting of a single ocelli at the midbase of each pectoral fin, paired small white spots, and no banding or crossbars on its tail vs numerous rosettes and whorls, no prominent ocelli at the pectoral fin bases, and 3-4 tail bands. The only other WIO Leucoraja species in the genus, L. compagnoi is known only from South Africa and has a short, blunt snout, a lower upper tooth count (38 vs 57 in L. elaineae sp. n.), a plain dorsal disc color with no markings and distinct bands on its tail. All other members of the genus occur in the North Atlantic, except one species that occurs in the eastern Central Atlantic and one in the eastern Indian Ocean.


Assuntos
Rajidae , Animais , Oceano Índico
4.
Zootaxa ; 4374(1): 91-98, 2018 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-29689815

RESUMO

The first record of the straptail fish, genus Macruronus, from South Africa was based on a single specimen captured off the Atlantic Cape coast and described as a new species, M. capensis Davies 1950. Davies did not examine specimens of the other extant nominal species in the genus, but based his conclusions solely on references to the original descriptions of M. novaezelandiae (Hector 1870) and M. magellanicus Lönnberg 1907. We show that all of the characters used by Davies (1950) to distinguish M. capensis from its congeners are in fact shared by the other nominal species of this genus. We also present molecular evidence from a Macruronus specimen recently caught off South Africa to support the conclusion that M. capensis is a junior synonym of M. novaezelandiae.


Assuntos
Gadiformes , Animais , Peixes , África do Sul
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