Extra-branchial processes manifest extra diversity: systematics of the genus Trapania (Nudibranchia: Goniodorididae) and nine new species descriptions

Trapania is a genus of dorid nudibranchs and one of the lesser studied members in the family Goniodorididae. Previous studies have been limited to using morphological data for producing phylogenies and establishing species relationships. This study presents the first molecular phylogeny for the genus Trapania with the goal of resolving questions that surfaced in previous morphological studies and enhancing our understanding of Trapania clade structure and species relationships. Bayesian inference, maximum likelihood and two types of species delimitation analyses reveal 15 previously described species and nine new species, which are described: Trapania kahel sp. nov., Trapania kamagong sp. nov., Trapania kanaloa sp. nov., Trapania lemanioides sp. nov., Trapania stegodon sp. nov., Trapania tamaraw sp. nov., Trapania tatsulok sp. nov., Trapania tigger sp. nov. and Trapania undulata sp. nov. Preliminary evidence presented here suggests that Atlantic and eastern Pacific species form a distinct clade and diverged from ancestors that were more widespread. An Indo-Pacific clade is sister to this clade, but stronger support and broader taxon sampling are required to test this hypothesis.

Automated summary

This study presents the first molecular phylogeny for the genus Trapania, revealing 15 previously described species and 9 new species. Preliminary evidence suggests the formation of distinct clades and provides insights into the species relationships.