Bond C.E., Yap-Chiongco M.K., Hawkins T., Partain R.E., Cobo M.C., Kocot K.M.
Aplacophorans are small vermiform molluscs with a world-wide distribution. Divided among two classes, Solenogastres (= Neomeniamorpha) and Caudofoveata (= Chaetodermomorpha) there are less than 500 formally described species although the true diversity of this group is estimated to be far greater. The biodiversity of solenogasters in the Norwegian Sea was thought to be well characterized, with 18 species described from this region. Here we present the preliminary result of the study of specimens obtained in 2011 and 2013 from the Icelandic marine Animals: Genetics and Ecology (IceAGE) expeditions. The family Gymnomeniidae was selected as five out of eight formally described species were described from the Norwegian Sea. Samples were sorted by morphotype based on habitus. Whole individuals for each morphotype were imaged via light and scanning electron microscopy and used for whole animal DNA extraction and amplification of 16s, COI, and Hsp 90 genes. Phylogenetic analyses were conducted with maximum likelihood analysis on a supermatrix of the three genes in IQ-TREE2 using the best fitting model and 1000 rapid bootstraps. Species delimitation using iPTP and Phylomap indicated between 25 and 38 different species within this region. To begin to unravel this unexpected diversity and confirm species delimitation, the morphology of the epidermal sclerites and characterization of important internal structures are necessary for formal description. Individuals within the same morphotype will be divided into three parts. Semi-thin sectioning of the anterior and posterior ends will be conducted for reconstruction of internal anatomy. The middle piece will be used for SEM under low-voltage for further characterization of the sclerites and used subsequently for DNA barcoding for placement on the tree. This work highlights the necessity for understanding of the true diversity of solenogaster aplacophorans as we continue to find new species, even in well characterized regions such as the Norwegian Sea.
Keywords: Aplacophora, Solenogastres, Norwegian Sea, Biodiversity, Taxonomy.
Acknowledgments: Specimens were graciously provided by IceAGE. The authors would also like to thank Tessa Hawkins for their contribution to this work.