First record of the Lessepsian nereidid Pseudonereis anomala Gravier, 1899 (Annelida: Nereididae) in the western Mediterranean Sea

This is the first record of the Lessepsian polychaete Pseudonereis anomala Gravier, 1899 in the western Mediterranean Sea, specifically in Skikda Bay, Algeria. The species was collected among rocks covered by algae at 0.5 m depth. A characterization of the species, as well as some ecological and distributional aspects are provided.