Phylogeography of the sea urchin Paracentrotus lividus (Lamarck) (Echinodermata:Echinoidea): first insights from the South Tyrrhenian Sea.

The sea urchin Paracentrotus lividus (Lamarck) (Echinodermata: Echinoidea) is an Atlanto-Mediterranean species abundant in the littoral zone, where it occurs in the sublittoral down to 20 m. The aim of our work is to investigate the genetic patterns of P. lividus along the South Tyrrhenian coasts. Five specimens were collected in six localities, from the Gulf of Naples and the Cilento coast. The nuclear rDNA ITS2 spacer and the two mitochondrial genes 16S and COI were used for the analysis. The three markers utilised did not show any structure among populations from the Gulf of Naples. All populations appear to be polyphyletic, with Cilento samples more differentiated from the others. This suggests the existence of phylogeographic structure at larger geographic scale. Absence of genetic structure has been interpreted taking into consideration theoretical dispersal of the planktotrophic larvae, which can survive for 4-8 weeks before settlement, marine current patterns and persistence of the species in the area. [ABSTRACT FROM AUTHOR]