Meeting Abstract
Dorid nudibranchs (Gastropoda: Nudipleura) are a key taxon for studying the evolution and interaction of chemical defense, color patterns and feeding specialization, yet we lack a sufficiently detailed phylogeny for hypothesis testing. New morphological characters would clearly help. One possibility is the interior spicule networks of dorids, but we know little about their form or how they vary within or among species. However, studying these networks typically requires clearing and staining, thus limiting the specimens that institutions are willing to lend. We compared traditional staining methods vs micro-CT of specimens representing 10 species of Aldisa, Cadlina and Onchidoris. We found that micro-CT offered a non-destructive view of sufficient resolution to study the gross morphology of networks, although fine structures images were too grainy to allow robust comparisons. Network form did not vary within species and was consistent within genera. The three genera varied in several obvious characters, such as presence of a blood channel, large dorsal spicules, and multispicular tracts, as well as in relative size, shape and orientation of spicules. This suggests these networks will prove a fruitful source of genus-level characters within phylogenies.
