Alcyonidium kuklinskii sp. nov., a new species of Antarctic ctenostome bryozoan with a key to all Antarctic species of the genus

Abstract:

Recent surveys of Antarctic waters in the Terra Nova Bay revealed numerous bryozoan species including ctenostome bryozoans. Whereas cheilostome bryozoans are well-studied in these latitudes, ctenostomes remain highly neglected. Large ctenostomes are easily addressed by their lack of calcified skeletons, but this lack also renders them difficult and tedious to identify. As a result, histology and reconstructions of internal soft tissues is required to classify this group of bryozoans. Thanks to the availability of new specimens from Terra Nova Bay, a detailed analysis of growth form, gut morphology and tentacle number of two colonies, initially ascribed to the ctenostome bryozoan genus Alcyonidum Lamouroux, 1813, turned out to be a new species, Alcyonidium kukliskii sp. nov., which we described in this study. These specimens were also barcoded (COI) and sequences compared to available ones. Together with the new species described here, a total of ten species of Alcyonidium is known for the Southern Ocean, accounting for one eight of the entire genus diversity. All Southern Ocean species appear to be endemic. In order to speed the identification of the Antarctic Alcyonidium species we provide an identification key and a distribution map of all type species. In brief, colony morphology, zooidal size and in particular tentacle number represent the most suitable characters for identifying species within this genus.