Ceratal arrangement in Phyllodesmium by Rudman, 1991

In : Rudman, W.B. (1991) Further studies on the taxonomy and biology of the octocoral-feeding genus Phyllodesmium Ehrenberg, 1831 (Nudibranchia: Aeolidoidea). Journal of Molluscan Studies, 57(2) : 167-203.

Suggested evolution within the genus Phyllodesmium based on ceratal arrangement and on adaptations to octocoral-feeding and zooxanthellae symbiosis

From basal species without zooxanthellae and an unbranched ceratal digestive two evolutionary lines can be derived :
            - One leads to the Xenia-feeders, P. crypticum, P. hyalinum and P. pecten, with temporary zooxanthellae retention
            - The other leads through P. poindimieri, with branched ceratal digestive gland, to those species with a well developed zooxanthellae-symbiosis

Rq : Actually seven Xeniidae-feeding species are described : Only P. hyalinum, P. crypticum and P. pecten are represented in this document, and not the 4 new species : P. jakobsenae (2004) , P. tuberculatum (2009), P. lembehensis (2008) and P. lizardensis (2008)