Deep-water crisiids (Bryozoa: Cyclostomata) from the northeast Atlantic Ocean

Abstract

Eight Crisia and two Bicrisia species are recorded from the Celtic Sea (330–1175 m, Thalassa, 1973) and from both sides of the Straits of Gibraltar (110–903 m, Cryos, Balgim). Two new species are described: Crisia pyrula n. sp., and Bicrisia gibraltarensis n. sp. Systematics and morphology of five other species are detailed. A southern morphotype of C. aculeata is distinguished. Except for the boreal species B. abyssicola, all species occur both in Atlantic and Mediterranean localities. The upper bathyal crisiid fauna (>200 m) is richer in the Celtic Sea than in the Gibraltar area (6 spp. vs. 3 spp). Only three crisiids seem to be true deep-water species. The crisiid stock from stations located in the Gulf of Cadiz in Atlantic water is twice as rich as (1) that from stations of the same area washed by the Mediterranean water outflow; (2) that from the Alboran Sea.

Keywords :

• Bryozoa
• Crisia
• Bicrisia
• taxonomy
• biogeography
• Celtic Sea
• Gibraltar area