Mating trials validate the use of DNA barcoding to reveal cryptic speciation of a marine bryozoan taxon

Abstract

Despite increasing threats to the marine environment, only a fraction of the biodiversity of the oceans has been described, owing in part to the widespread occurrence of cryptic species. DNA-based barcoding through screening of an orthologous reference gene has been proposed as a powerful tool to uncover biological diversity in the face of dwindling taxonomic expertise and the limitations of traditional species identification. Although DNA barcoding should be particularly useful in the sea, given the prevalence of marine cryptic species, the link between taxa identified through DNA barcodes and reproductively isolated taxa (biological species) has rarely been explicitly tested. Here, we use an integrated framework comparing breeding compatibility, morphology and mitochondrial (cytochrome c oxidase 1) and nuclear (elongation factor-1-alpha) DNA sequence variation among globally distributed samples of the cosmopolitan marine bryozoan Celleporella hyalina (L.). Our results reveal that C. hyalina comprises numerous deep, mostly allopatric, genetic lineages that are reproductively isolated, yet share very similar morphology, indicating rampant cryptic speciation. The close correspondence between genetic lineages and reproductively isolated taxa in the context of minimal morphological change suggests that DNA barcoding will play a leading role in uncovering the hidden biodiversity of the oceans and that the sole use of morphologically based taxonomy would grossly underestimate the number of marine species.

Four years of DNA barcoding: Current advances and prospects

“…The efficiency of DNA barcoding has been reported in the detection and description of new cryptic species (Hansfield and Hansfield, 2006;Smith et al, 2006b;Anker et al, 2007;Bucklin et al, 2007;Gomez et al, 2007;Pfenninger et al, 2007;Tavares and Baker, 2008) and of sibling species (Hogg and Hebert, 2004;Amaral et al, 2007;Van Velzen et al, 2007). This identification tool can clearly give support to improve classifications and to critically examine the precision of morphological traits commonly used in taxonomy.…”

Bird migratory flyways influence the phylogeography of the invasive brine shrimp Artemia franciscana in its native American range

“…The COI gene is one of the most widely used tools for species delineation (Hebert, Penton, et al 2004;Costa et al 2007;Gómez, Wright, et al 2007). Sequence divergence of 3% have been proposed as a threshold for species delimitation in crustaceans (Costa et al 2007, but see Lefébure et al 2006), but other approaches are also used, such as GMYC (Pons et al 2009) or automatic barcode delimitation, which we used here (Puillandre et al 2012).…”

Molecular species discovery in the diatom Sellaphora and its congruence with mating trials.

“…Correlation between different molecular markers, and with other properties such as morphology, reproductive isolation, or ecology, provides further evidence for the presence of distinct species (e.g. Gómez et al 2007;Burns et al 2008;Jargeat et al 2010;Tronholm et al 2010), based on the general notion of species as separately evolving metapopulation lineages (De Queiroz 2007). In groups with a large proportion of (pseudo)cryptic or unstudied species, the availability of model species complexes with well-understood species limits based on a range of properties can be highly useful, for instance to investigate the performance of different molecular markers for large-scale phylogenetic species delimitation (such as applied by e.g.…”