Influence of colony morphology on associated biota diversity in four Bryozoa

The potential role of four erect, calcified (Cheilostomatida, Ascophorina) bryozoans in providing habitat for other organisms has been analysed. Samples of Myriapora irimcala, Smittina cervicornis, Reteporella cmichii, Pentapora fascialis , collected in the Ligurian Sea (NW Mediterranean), were assigned to four morphological types according to their increasing morphological complexity: ‘tree’, ‘bush’, ‘convolute laminae’, ‘anastomosed, convolute laminae’. 22 species, belonging to 7 higher taxonomic levels, were found associated with the ‘tree’ morphotype, 27 species (7 higher taxonomic levels) were found in ‘bush’ morphotype, 37 species (9 higher taxonomic levels) were identified among ‘convolute laminae’, whereas ‘anastomosed, convolute laminae’, provided habitat for 84 species (13 higher taxonomic levels). Species richness of associate biota increased with increasing morphological diversity. The position of associated biota inside the colonies was correlated to organism growth form and feeding behaviour. In particular, a relationship was found between species richness, abundance of associated bryozoan species and morphological diversity. All the growth habits displayed by associated bryozoan species found suitable habitat in the most complex morphotype.