A copy of the manuscript submitted to the journal Marine Biodiversity and edited by the authors. 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 hot-spot 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 improveourknowledge onpoorly studied phyla,such as bryozoans. In 14 ofthe 21 samples examined duringthis study, 43bryozoan taxacould be identified. Among these, one species is described as new to science (Buskeamedwavessp. nov.) and three other ones are reported for the first time fromthe Mediterranean Sea, namelyTerminoflustra barleei(Busk, 1860), Marguetta pulchraJullien in Jullien & Calvet,1903, and Schizomavella (Schizomavella) linearis profunda Harmelin & d’Hondt, 1992. Some species were abundant in the samples, such as Adeonellopsis distoma (Busk, 1859), B.medwavessp. nov., Entalophoroecia cf. deflexa, 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 to other bottom types and habitats such as sandy bottoms and muddy bottoms. The finding highlights the importance of these environments for bryozoans.