Patterns of lineage diversification in the Genus Naso (Acanthuridae)

Klanten, Selma O., van Herwerden, Lynne, Choat, J.Howard, and Blair, David (2004) Patterns of lineage diversification in the Genus Naso (Acanthuridae). Molecular Phylogenetics and Evolution, 32 (1). pp. 221-235.

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Abstract

The evolutionary history of the reef fish genus Naso (F. Acanthuridae) was examined using a complete species-level molecular phylogeny of all recognized (19) species based on three loci (one nuclear ETS2 and two mitochondrial 16S, cyt b). This study demonstrates that distinct foraging modes and specialized body shapes arose independently at different times in the evolutionary history of the genus. Members of the subgenus Axinurus, characterized by a scombriform morphology, caudal fin structure and pelagic foraging mode, were consistently placed basal to the remaining Naso species, suggesting that pelagic foraging is plesiomorphic and benthic foraging derived in this genus. We used a genus-level phylogeny (nuclear marker, ETS2), which included several taxa from all other acanthurid genera, to obtain a range of age estimates for the most recent common ancestor of the genus Naso. These age estimates (range of 52–43.3 MY) were then used to estimate divergence times (by nonparametric rate smoothing method) of the node giving rise to extant Naso species using the combined sequence data (from all loci). The reconstruction of the pattern of divergence of extant species indicates two sequences of events. The basal species characterized by pelagic foraging modes arose during the Eocene and Oligocene. Most of the remaining Naso species, including those characterized by benthic foraging, arose over a period of 20 MY during the Miocene. Diversification during this period was associated with major plate tectonic and glaciation events, resulting in changes in sea level, ocean temperature and productivity regimes. Regardless of the foraging mode exhibited, all species of Naso have a caudal propulsive unit similar to that observed in pelagic scombriform fishes, a legacy of the basal position of the subgenus Axinurus in the phylogeny of the genus.

Item ID: 6926
Item Type: Article (Refereed Research - C1)
Keywords: Acanthuridae; foraging mode; fossil record; lineage diversification; molecular phylogeny; Morphology; Nonparametric rate smoothing
ISSN: 1095-9513
Date Deposited: 15 Feb 2010 04:58
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060409 Molecular Evolution @ 50%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 25%
06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060302 Biogeography and Phylogeography @ 25%
SEO Codes: 96 ENVIRONMENT > 9699 Other Environment > 969999 Environment not elsewhere classified @ 51%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 49%
Citation Count from Web of Science Web of Science 37
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