Radiações múltiplas de girinos camarões desafiam o conceito de 'fósseis vivos'
quinta-feira, abril 04, 2013
Multiple global radiations in tadpole shrimps challenge the concept of ‘living fossils’
Thomas C. Mathers1, Robert L. Hammond2, Ronald A. Jenner3, Bernd Hänfling1, Africa Gómez 1
Author and article information
1 School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, UK
2 Department of Biology, University of Leicester, Leicester, UK
3 Life Sciences Department, The Natural History Museum, London, UK
DOI 10.7717/peerj.62
Abstract
‘Living fossils’, a
phrase first coined by Darwin, are defined as species with limited
recent diversification and high morphological stasis over long periods
of evolutionary time. Morphological stasis, however, can potentially
lead to diversification rates being underestimated. Notostraca, or
tadpole shrimps, is an ancient, globally distributed order of
branchiopod crustaceans regarded as ‘living fossils’ because their rich
fossil record dates back to the early Devonian and their morphology is
highly conserved. Recent phylogenetic reconstructions have shown a
strong biogeographic signal, suggesting diversification due to
continental breakup, and widespread cryptic speciation. However,
morphological conservatism makes it difficult to place fossil taxa in a
phylogenetic context. Here we reveal for the first time the timing and
tempo of tadpole shrimp diversification by inferring a robust multilocus
phylogeny of Branchiopoda and applying Bayesian divergence dating
techniques using reliable fossil calibrations external to Notostraca.
Our results suggest at least two bouts of global radiation in
Notostraca, one of them recent, so questioning the validity of the
‘living fossils’ concept in groups where cryptic speciation is
widespread.
Cite this as
Mathers et al. (2013)
Multiple global radiations in tadpole shrimps challenge the concept of
‘living fossils’. PeerJ 1:e62 http://dx.doi.org/10.7717/peerj.62
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