Morphological and mitochondrial DNA divergence validates blackmouth, Galeus melastomus, and Atlantic sawtail catsharks, Galeus atlanticus, as separate species

Castilho, Rita; Freitas, M.; Silva, Gabriela; Fernandez-Carvalho, Joana; Coelho, R.

http://hdl.handle.net/10400.1/4086

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Authors

Castilho, Rita

Freitas, M.

Silva, Gabriela

Fernandez-Carvalho, Joana

Coelho, R.

Abstract(s)

A total of 60 morphometric traits and nucleotide sequences of the entire mtDNA NADH dehydrogenase subunit 2 (ND2) gene [1047 base pair (bp)] in 23 individuals of blackmouth, Galeus melastomus, and 13 individuals of sawtail catsharks, Galeus atlanticus, caught in Southern Portugal, were examined to test the validity of these two taxa. These sharks closely resemble each other, have overlapping geographical ranges and are difficult to identify by morphological characters. Non-metric multidimensional scaling of morphometric variables indicates a clear separation between the two species, with 10 characters each contributing 2 12–2 45% of the total variability between species. Maximum likelihood, parsimony and neighbour-joining trees revealed two major mtDNA haplotype clades, corresponding to the two species, with an average corrected sequence divergence between them of 3.39 +- 0.56%. Within species divergences between haplotypes averaged 0.27 +- 0.18% in G. melastomus and 0.12 +- 0.08% in G. atlanticus. A total of 35 diagnostic nucleotide site differences and four restriction fragment length polymorphism recognition sites in the ND2 gene can be used to distinguish the two species.

Keywords

Catsharks Delimiting species Elasmobranch Mitochondrial DNA ND2 gene mt DNA

URI

http://hdl.handle.net/10400.1/4086

Citation

Castilho, Rita; Freitas, M; Silva, G; Fernandez-Carvalho, J; Coelho, R. Morphological and mitochondrial DNA divergence validates blackmouth, Galeus melastomus, and Atlantic sawtail catsharks, Galeus atlanticus, as separate species, Morphological and mitochondrial DNA divergence validates blackmouth, Galeus melastomus, and Atlantic sawtail catsharks, Galeus atlanticus, as separate species, Journal of Fish Biology, 70, Suppleme C, 346-358, 2007.