Loricate choanoflagellates (Acanthoecidae) from warm water seas. II. Bicosta, Apheloecion, Campyloacantha, Crucispina, Calliacantha and Saroeca

The main outcome of this and subsequent papers is to provide a baseline survey of heterotrophic protist diversity from warm water marine ecosystems, exemplified by loricate choanoflagellates (Acanthoecidae). Genera in focus here (i.e. Bicosta, Apheloecion, Campyloacantha, Crucispina, Calliacantha and Saroeca) possess anterior spines or projections and a posterior pedicel, and have 0, 1 or 2 transverse costae. Longitudinal costae are, with the exception of Campyloacantha, external to transverse costal elements across all genera examined here. We describe here Apheloecion eqpacia sp. nov. and Calliacantha magna sp. nov., both of which are so far distributionally confined to warm water habitats. A ‘form A’ of Bicosta minor is introduced to facilitate the distinction between B. minor sensu stricto and a presumed warm water adapted variant with a posterior lorica chamber twist of the longitudinal costae