Y-Naupli (Crustacea, Thecostraca, Facetotecta) from coastal waters of the Salento Peninsula (south eastern Italy, Mediterranean Sea) with descriptions of four new species

A collection ( 102 specimens of four different types) of Facetotecta nauplii ("Y-nauplii") is described. It derives from different zooplankton samples collected between 1996 and 2004 at seven sites around the Salento Peninsula, south eastern Italy, the Mediterranean Sea. The collection sites ( rocky coasts, submerged grottoes, one brackish water basin) are characterized by different salinity and bottom conditions. This is the first report of F. nauplii from a coastal brackish water pond. The nauplii belonged to types I, IV, VII, and IX of the current informal classification. This is the first report of types I, VII, and IX from the Mediterranean Sea. Types VII and IX are new also for Europe. Given the lack of the cypris-larva stage in this collection, the nauplius morphology is here proposed as valid to identify species. Some morphological features of the specimens presented here are not shared with any nauplius described from other parts of the world. On the basis of these differences four new species have been described ( in alphabetic order: Hansenocaris corvinae, H. leucadea, H. mediterranea, H. salentina).