Morphology of planktonic zoeal stages of Palicus caronii (Decapoda, Brachyura), identified by DNA barcoding, provides novelties to Palicoidea larval systematics

The zoeal development of the brachyuran crab, Palicus caronii, comprises two zoeal stages and the morphology is described and illustrated in detail. The zoeae were collected in plankton samples from the Southern Ligurian Sea (Western Mediterranean). Although the morphology of the larval stages of this species was unknown, a combination of characters allowed the zoeae to initially be assigned to the Palicidae, based on the previous unique known first zoeal description of one species of this family. Later, the identification of the larvae as Palicus caronii was confirmed through molecular analysis. The morphological features of the zoeae that characterize the Palicidae and separate them from the Crossotonotidae are confirmed. Also, the larval development comprising only two zoeal stages observed in Palicus caronii, the peculiar and uncommon carapace surface setation, and the presence of anterodorsal and posterodorsal sensory dorsal organs suggest that these characters could be common to the Palicoidea.The collection of the larval stages used in the present work was performed in the context of a project carried out with the financial support of the Italian Ministero della Salute (Research Project IZSPLV 14/14 RC). COI sequence of adult crab of Palicus caronii was obtained within the framework of the MEGALOPADN project (CGL2009-11225) funded by the “Ministerio de Economía y Competividad (MINECO)” Spanish Plan R + D + I and FEDER. Authors would like to thank Prof. Simona Bonelli, Department of Life Sciences and Systems Biology (UNITO), for her support, and the entomology laboratory of Department of Agriculture, Forestry and Food Sciences (UNITO) for loaning the camera lucida, with a special thanks to Enrico Busato for his availability. The study was funded by the Italian Ministero della Salute (Research Project IZSPLV 14/14 RC)