ABSTRACT: Molecular taxonomy is one of the most promising yet challenging fields of biology. Molecular markers such as nuclear and mitochondrial genes are being used in a variety of studies surveying marine nematode taxa. Sequences from more than 600 species have been deposited to date in online databases. These barcode sequences are assigned to 150 nominal species from 104 genera. There are 41 species assigned to Enoplea and 109 species to Chromadorea. Morphology-based surveys are greatly limited by processing speed, while barcoding approaches for nematodes are hampered by difficulties in matching sequence data with morphology-based taxonomy. DNA barcoding is a promising approach because some genes contain variable regions that are useful to discriminate species boundaries, discover cryptic species, quantify biodiversity and analyse phylogeny. We advocate a combination of several approaches in studies of molecular taxonomy, DNA barcoding and conventional taxonomy as a necessary step to enhance the knowledge of biodiversity of marine nematodes. Keywords – barcoding, marine nematodes, molecular markers, molecular taxonomy. The phylum Nematoda exhibits high species diversity, as well as high abundances in aquatic (marine or freshwa-ter) and terrestrial environments (Floyd et al., 2002). Ne-matoda in general are one of the most diverse taxa in the animal kingdom, with estimates ranging from 0.1 to 100 million species (Lambshead, 1993; Coomans, 2002). Only a few thousand of these species have been described, al-though they represent the most abundant component of the meiofauna in several kinds of ecosystems (Lambshead, 2004; Bhadury et al., 2006a).
Nematology 01/2010; 12:661-672. · 0.91 Impact Factor