Antarctic waters represent a unique marine environment delimited by an oceanographic barrier, the Polar Front Zone, and characterized by constant subzero temperatures and presence of sea ice. A group of teleost fish, the Notothenioidei, have adapted to these challenging environmental conditions, undergoing a remarkable diversification. In the present study a total of 798 base pairs, generated from partial sequencing of 16S and 12S mitochondrial ribosomal RNA genes, were examined in 33 notothenioid species representative of all families included in the suborder Notothenioidei. Phylogenetic trees, reconstructed on the basis of sequence data by different methods, indicate that traditional hypotheses on notothenioid systematics and biogeography might be in need of reexamination. Molecular evidence suggests that vicariant speciation could be invoked to explain the early divergence of Eleginops maclovinus, a species previously included in the family Nototheniidae, which is now proposed as the closest sister group to all the rest of notothenioids apart from bovichtids. On the other hand, repeated, independent dispersal through the Polar Front is proposed for the divergence of other subantarctic notothenioid species. Likewise, multiple, independent transitions from benthic to pelagic habit are inferred from molecular data, at variance with the more conservative hypothesis based on cladograms reconstructed from morphological data.

Mitochondrial phylogeny of notothenioids: A molecular approach to antarctic fish evolution and biogeography

BARGELLONI, LUCA;MARCATO, STEFANIA;ZANE, LORENZO;PATARNELLO, TOMASO
2000

Abstract

Antarctic waters represent a unique marine environment delimited by an oceanographic barrier, the Polar Front Zone, and characterized by constant subzero temperatures and presence of sea ice. A group of teleost fish, the Notothenioidei, have adapted to these challenging environmental conditions, undergoing a remarkable diversification. In the present study a total of 798 base pairs, generated from partial sequencing of 16S and 12S mitochondrial ribosomal RNA genes, were examined in 33 notothenioid species representative of all families included in the suborder Notothenioidei. Phylogenetic trees, reconstructed on the basis of sequence data by different methods, indicate that traditional hypotheses on notothenioid systematics and biogeography might be in need of reexamination. Molecular evidence suggests that vicariant speciation could be invoked to explain the early divergence of Eleginops maclovinus, a species previously included in the family Nototheniidae, which is now proposed as the closest sister group to all the rest of notothenioids apart from bovichtids. On the other hand, repeated, independent dispersal through the Polar Front is proposed for the divergence of other subantarctic notothenioid species. Likewise, multiple, independent transitions from benthic to pelagic habit are inferred from molecular data, at variance with the more conservative hypothesis based on cladograms reconstructed from morphological data.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2458326
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 127
social impact