Many marine invertebrates present complex life cycles comprising several developmental stages which clearly differ morphologically from those finally reached by adults. This is the case in the brachyuran crustacean decapods. Most brachyuran crabs pass through a planktonic larval period with two phases, zoea and megalopa, which are very different from each other and from the adult form. This represents an important drawback in the identification of the brachyuran larvae collected from plankton. The main objective of the present study is the use of molecular techniques, DNA barcodes (mitochondrial DNA sequences 16S and Cox1), and morphological analysis, in the accurate identification of Iberian brachyuran megalopae obtained directly from planktonic samples. We have presently identified 36 different planktonic megalopae after examination of more than 2100 specimens. Twenty-six of them are megalopae of species already described from laboratory cultures that have been revised in order to look for differences with respect to wild specimens. Moreover, some of them also need to be re-described, considering that previous published descriptions were inaccurate or incomplete (i.e. Rhithropanopeus harrisii, Dyspanopeus sayi, Percnon gibbesi). Ten megalopae unknown until now (Sirpus zariquieyi, Derilambrus angulifrons, Polybius zariquieyi, Ergasticus clouei, Afropinnotheres monodi, between others) will be described in detail. These new descriptions, together with the formerly existing ones, will allow the creation of an illustrated identification key, as a final objective, addressed to researchers and technicians, which is intended to assist in the correct identification of this important group of planktonic organisms

The Crustacean Society & Latin American Association of Carcinology Summer Meeting, Costa Rica, San José, 07-11 July 2013

Peer Reviewed