Report of two Mediterranean species of Stephos T. Scott, 1892 (Copepoda: Calanoida) in the North-East Atlantic Ocean (Brittany, France), with a note on the "hyaline sheath" in the genus Stephos.
Stephos cryptospinosus Zagami, Campolmi and Costanzo, 2000 and Stephos marsalensis Costanzo, Campolmi and Zagami, 2000 were found at Concarneau (Brittany, France). These species were originally described at the same locality on the island of Sicily (Italy) in the western Mediterranean. This report is the first record of either species from outside the Mediterranean Basin. The description of S. cryptospinosus is supplemented with SEM observations, and compared with the original. In addition, the role of the hyaline sheath covering the genital doublesomite of the female in some species of Stephos is discussed.