Sea lice (Copepoda: Caligidae) of Turkey, with the discovery of Caligus quadratus Shiino, 1954 in the Mediterranean Sea and the re-description of a rare caligid copepod, Caligus scribae Essafi, Cabral & Raibaut, 1984.

The current status of the caligid copepods parasitic on marine fishes off Turkey is reviewed and an updated checklist comprising a total of 24 species, belonging to three different genera, Caligus O. F. Müller, 1785, Euryphorus H. Milne Edwards, 1840 and Lepeophtheirus von Nordmann, 1832, is presented together with habitus illustrations and a key to all 24 species. Two of the species of caligids listed herein constitute new records for Turkish waters. The first, Caligus quadratus Shiino, 1954, a well-known species of the genus, was collected from the common dolphin fish, Coryphaena hippurus Linnaeus. The second, Caligus scribae Essafi, Cabral & Raibaut, 1984, a very rare and poorly known member of the genus, was sampled from a new teleost host, the parrot fish, Sparisoma cretense (Linnaeus). Both fish species were caught in north-eastern Mediterranean waters off the Turkish coast. Caligus quadratus is only briefly described based on key diagnostic characters whereas a full re-description is provided for C. scribae, as the only description available for this species is incomplete and lacks detail. Sparisoma cretense is a new host record for C. scribae. In addition, this is the first report of C. quadratus from the Mediterranean.