Bryozoans from Chella Bank (Seco de los Olivos), with the description of a new species and some new records for the Mediterranean Sea

Chella Bank (also known as Seco de los Olivos seamount) is a volcanic submarine elevation (76–700 m deep) located ca. 16 km off the southern coast of Spain, within the Alboran Sea, in the Atlantic-Mediterranean transition zone. It represents a biodiversity hotspot for Europe, with more than 600 species listed to date, and contains several habitats included in the EU Habitats Directive. During three ship-based expeditions, several areas of Chella Bank were surveyed and sampled in a depth range of 95–729 m, resulting in new records that improve our knowledge on poorly studied phyla, such as bryozoans. In 14 of the 21 samples examined during this study, 43 bryozoan taxa could be identified. Among these, one species is described as new to science ( Buskea medwaves sp. nov.) and three other ones are reported for the first time from the Mediterranean Sea, namely Terminoflustra barleei (Busk, 1860 ), Marguetta pulchra Jullien in Jullien & Calvet, 1903 , and Schizomavella ( Schizomavella ) linearis profunda Harmelin & d’Hondt, 1992a . Some species were abundant in the samples, such as Adeonellopsis distoma (Busk, 1859 ), B. medwaves sp. nov., Entalophoroecia cf. deflexa , and Reteporella pelecanus López de la Cuadra & García-Gómez, 2001 . The highest species richness was detected in rhodolith beds and on coral rubble bottoms (especially exposed above the sediments) compared with other bottom types and habitats such as sandy bottoms and muddy bottoms. The finding highlights the importance of these environments for bryozoans.