Diversity of hydrothermal vent decapods at Tofua Arc in the Southwest Pacific using the CO1 barcoding

Abstract

Decapods (i.e., shrimps and crabs) are one of the most abundant and common organisms at vent fields. However, their identification based on morphological characteristics is often leaded to incorrect recognition of species due to the existence of sibling (or cryptic) species. Recently DNA sequences are a useful tool for the identification of species and the mitochondrial cytochrome c oxidase subunit I (COI) sequences are being widely used as the DNA barcode region for animals. It is primarily determined the appropriate thresholds in target taxa for species discrimination using COI. Vent decapods were collected from hydrothermal vent fields at Tofua Arc in the Southwest Pacific on April 2011 and February 2012 using ROV. The intra- and inter-specific variations were calculated by Mega 5.05 using 44 COI sequences newly determined from vent shrimps and crabs with sequences of the family Alvinocarididae and Bythograeidae retrived from GenBank. We defined the thresholds of the molecular operational taxonomic units (MOTU) for the family Alvinocarididae and Bythograeidae. Then 44 COI sequences were separated into six MOTUs; four crab groups (Austinograea sp., Euryxanthops sp., Gandalfus puia, Xenograpsus sp.) and two shrimp groups (Nautilocaris saintlaurentae, Opaepele sp.). These results will be very helpful to assess the evolutionary relationships and biogeographic distribution of vent endemic orstence of sibling (or cryptic) species. Recently DNA sequences are a useful tool for the identification of species and the mitochondrial cytochrome c oxidase subunit I (COI) sequences are being widely used as the DNA barcode region for animals. It is primarily determined the appropriate thresholds in target taxa for species discrimination using COI. Vent decapods were collected from hydrothermal vent fields at Tofua Arc in the Southwest Pacific on April 2011 and February 2012 using ROV. The intra- and inter-specific variations were calculated