Findings of Phyllosoma Larvae and Nistos of the Family Scyllaridae (Crustacea, Decapoda) in the Southern Mediterranean Sea

Abstract

The rare findings of specimens in larval or post-larval stages (6 phyllosomas and 7 nistos/early juveniles) belonging to the family Scyllaridae are reported for the waters around Sicily. Some were stranded on different winter occasions near the Strait of Messina (north-eastern Sicily), while others were collected during experimental trawl surveys carried out in the Sicilian Channel, at depths up to 450 m. All phyllosoma instars were in advanced stages of development; however, the absence of complete morphological references on the larval characteristics of the family Scyllaridae, necessary for distinguishing the different genera (Scyllarus and Scyllarides, small or large slipper lobsters, or the extremely rare Acantharctus) and species inhabiting the Mediterranean, did not allow to attribute the phyllosomas to a specific taxon. On the contrary, apart from one nisto without apparent lobes (maybe belonging to the species Scyllarides latus), nistos/early juveniles could be classified at generic level on the basis of similarities with the morphology of adult antennae, as pertaining to the genus Scyllarus, but the characters of juveniles are in general ineffective to discriminate between Scyllarus arctus and Scyllarus pygmaeus (the only two known Central Mediterranean species); in fact, the small size and the depth at which they settled suggested that some may belong to the smaller, deeper species Scyllarus pygmaeus.