Four genes, morphology and ecology:: distinguishing a new species of Acesta (Mollusca; Bivalvia) from the Gulf of Mexico

There is currently an active scientific debate about the most correct and efficient way to identify species. To date, few studies in the marine realm have combined the available taxonomic methods. In this study we have used morphology, ecology and molecular analyses to identify a new species within the bivalve genus Acesta. All four genes studied (12S, 16S, Cytb, COI) suggested that a common cold-seep species in the Gulf of Mexico, A. bullisi, should be divided into two distinct species. This conclusion was supported by morphological traits and by observations of ecological distribution. A. oophaga Jarnegren, Schander and Young n. sp. is described here, and A. bullisi Vokes (Tulane Stud Geol 2:75-92, 1963) is re-described. This study shows that DNA barcoding in combination with traditional morphological and ecological analyses may be an important tools to identify hidden biodiversity among deep-water organisms such as bivalves.