Mesaiokeras hurei n. sp. (Copepoda, Calanoida, Mesaiokeratidae) from the Adriatic Sea

A new species of Mesaiokeras is described from the hyperbenthosof Veliko Jezero, a marine lake on the island of Mljet, Croatia.This is the first species of this genus and family (Mesaiokeratidae)reported from the Adriatic and Mediterranean seas. It is characterizedby small body length (an average 361 µm for females and337 µm for males), the low number of free segments (21)and the armature of the antennules, very long spine (a₂) ofexopodite I of female right leg 4, the presence of long processeson the ventroposterior area of the female genital double-somite,the form and surface ornamentation of the genital area, theform and ornamentation of male and female leg 5, and the formand armature of caudal rami. This species was found in shallowwater with very stable hydrographic conditions and at a populationdensity from 1 to 26 ind. m^-3.