First record of Zoantharia in the Black Sea: Isozoanthus cf. sulcatus reared from planulae

The first record of a species from the order Zoantharia in the Black Sea is given. Zoantharians were successfully reared from planktonic larvae collected in a single planktonic net haul conducted in shallow coastal waters of the Golubaya Bay, Gelendzhik area, Caucasus. The larvae were subsequently settled in a small glass container and resulting colonies were maintained in an aquarium with a salinity level of 18 psu for approximately nine months, but in June 2018 all colonies died due to uncontrolled bloom of filamentous algae. The presence of symbiotic algae of the family Symbiodiniacea in tissues of colonies is shown. Phylogenetic analysis using mitochondrial (COI) markers revealed a high degree of similarity between the Black Sea zoantharian and Isozoanthus sulcatus (Gosse 1860) from European seas.