Resumen
Investigation of bryozoan faunas collected in two submarine caves in Lesvos Island, Aegean Sea revealed a great number of colonies of three species currently assigned to the cheilostome family Onychocellidae: Onychocella marioni Jullien, 1882, O. vibraculifera Neviani, 1895, and Smittipora disjuncta Canu & Bassler, 1930. All species were first described and subsequently recorded on several occasions, from the Mediterranean Sea, particularly from the Aegean Sea. The availability of this material provided the basis for more detailed observations and first scanning electron microscopy (SEM) study of some diagnostic characters, including ovicells and ancestrulae, for the well-known species, as well as a few colonies of a species left in open nomenclature (i.e., Onychocellidae sp. 1) in previous works. In this paper we (i) update the descriptions of these four species; (ii) resurrect the species Floridinella arculifera Canu & Bassler, 1927, which was previously synonymised with Caleschara minuta (Maplestone, 1909), suggesting for it the new combination Tretosina arculifera; (iii) and introduce the new genus Bryobifallax for S. disjuncta.