The discovery of the male of Caligus ligusticus Brian, 1906 (Copepoda: Caligidae) parasitic on the sand steenbras Lithognathus mormyrus (L.) in the eastern Mediterranean.

Caligus ligusticus Brian, 1906 (Copepoda: Caligidae), a species of parasitic copepod originally based on females collected from off Genova, Italy, is redescribed based on newly collected specimens of both sexes. The new material was collected from the inner opercular surface of the sand steenbras Lithognathus mormyrus (Linnaeus) caught in eastern Mediterranean waters off the Turkish coast. Inadequately described female structures from earlier descriptions are re-described and illustrated in detail and the male of C. ligusticus is described for the first time. Key diagnostic characters of C. ligusticus are highlighted by scanning electron microscopy observations. A comparative study of the newly collected specimens of C. ligusticus and material collected by A. Brian and stored in the collections of the Muséum National d'Histoire Naturelle in Paris, is also presented.