DNA barcoding and phylogeny in the family Mactridae (Bivalvia: Heterodonta): Evidence for cryptic species

Species boundaries of some Mactridae species are difficult to define by morphology due to phenotypic plasticity and morphological convergence. DNA barcoding might provide an effective resolution for the confusion. Here, partial sequences of mitochondrial cytochrome c oxidase subunit I (COI) and 16S rRNA genes from 36 specimens of 11 species are sequenced to assess whether Mactridae species could be distinguished by DNA barcoding techniques. An evident barcoding gap was detected in the COI analyses, while barcoding gap for 16S was not found. Nevertheless, neighbour-joining and Bayesian trees showed that all species but one (Coelomactra antiquata) fell into reciprocally monophyletic clades with high bootstrap support. Results of sequence divergence and topology in Bayesian inference of phylogenetic tree suggested the occurrence of potential cryptic or sibling species in the C. antiquata group. This study demonstrates the efficacy of species identification in Mactridae species via DNA barcoding. (C) 2012 Elsevier Ltd. All rights reserved.