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Data from: Phylogenomics of Aplacophora (Mollusca, Aculifera) and a solenogaster without a foot

Cite this dataset

Kocot, Kevin M.; Todt, Christiane; Mikkelsen, Nina T.; Halanych, Kenneth M. (2019). Data from: Phylogenomics of Aplacophora (Mollusca, Aculifera) and a solenogaster without a foot [Dataset]. Dryad.


Recent molecular phylogenetic investigations strongly supported placement of the shell-less, worm-shaped aplacophoran molluscs (Solenogastres and Caudofoveata) and chitons (Polyplacophora) in a clade called Aculifera, which is the sister taxon of all other molluscs. Thus, understanding the evolutionary history of aculiferan molluscs is important for understanding early molluscan evolution. In particular, fundamental questions about evolutionary relationships within Aplacophora have long been unanswered. Here, we supplemented the paucity of available data with transcriptomes from 25 aculiferans and conducted phylogenomic analyses on datasets with up to 525 genes and 75,914 amino acid positions. Our results indicate that aplacophoran taxonomy requires revision as several traditionally recognized groups are non-monophyletic. Most notably, Cavibelonia, the solenogaster taxon defined by hollow sclerites, is polyphyletic, suggesting parallel evolution of hollow sclerites in multiple lineages. Moreover, we describe Apodomenia enigmatica sp. nov., a bizarre new species that appears to be a morphological intermediate between Solenogastres and Caudofoveata. This animal is not a missing link however; molecular and morphological studies show that it is a derived solenogaster that lacks a foot, mantle cavity, and radula. Taken together, these results shed light on the evolutionary history of Aplacophora and reveal a surprising degree of morphological plasticity within the group.

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National Science Foundation, Award: This study was supported in part by awards from the U.S. National Science Foundation to KMK (DEB-1210518 and DBI-1306538) and KMH (DEB-1036537, OCE-1155188, ANT-1043745) and an award from the Norwegian Taxonomy Initiative (project #70184222) to Christiane Todt.