Phylogenetic systematics and zoogeography of Australian nudibranchs

Abstract

Thecacera boyla n.sp is described from coastal northern Queensland. Its most striking character is the elaboration of the rhinophoral sheaths into long, mobile “tentacles” that serve as sensory appendages, apparently in lieu of velar papillae. The genus Thecacera is holophyletic and probably derived from Polycera – like polycerids. Because four (possibly five) of the six valid biological species are tropical, it is probable Thecacera is tropically centered. There appears to be a gradient of decreasing species diversity eastwards from southeastern Africa.