Abstract:
Aplacophorans are shell-less, vermiform, marine mollusks that have a cuticle covered in calcareous scales or spines called sclerites. They are found worldwide in benthic marine habitats and are ecologically important to the deep sea. There has been a recent increase in aplacophoran research but even still, there is an extreme lack of knowledge about the true diversity of this class. To date, fewer than 500 species have been described even though this number is predicted to be ten times higher. Identifying aplacophorans to the genus and species level usually requires the use of histological methods to characterize internal anatomy, such as the radula, ventolateral foregut glands, and reproductive organs. Since studying aplacophoran taxonomy purely on morphology may be challenging, modern approaches are increasingly combining morphological data with molecular data (when possible) for a more reliable valuation of biodiversity. To advance our understanding of the biodiversity and evolutionary history of Aplacophora, an integrative taxonomic approach was used to characterize, identify, and describe three novel species of solenogaster species from New Zealand. Additionally, to improve our understanding of aplacophoran evolutionary history, the phylogeny of the aplacophoran class Caudofoveata was assessed by sequencing the mitochondrial genomes of representatives from the poorly known taxa Limifossor (Family Limifossoridae) and Prochaetodermatidae. Results revealed that Limifossoridae is non-monophyletic with Chaetodermatidae nested within.
