Asterocheres faroensis, a new species (Copepoda, Siphonostomatoida, Asterocheridae) associated with Hymeniacidon perlevis (Montagu, 1812) (Porifera) from Lake Faro, Mediterranean Sea.

A new siphonostomatoid copepod belonging to the family Asterocheridae, Asterocheres faroensis, is described. It was found in washings of Hymeniacidon perlevis (Montagu, 1812), a sponge inhabiting Lake Faro at Messina (north-eastern Sicily). The new species belongs to the cluster of species with 21 antennular segments in the female but only 17 in the male, and resembles those species carrying a 1-segmented mandibular palp. However, it differs from the latter in the length to width ratio of the P5. The males have a particular aesthetasc on the tenth antennular segment, a character that has never been found in other species of the family Asterocheridae.