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Systematics, phylogeny and biogeography
RESEARCH ARTICLE

Four new Solenogastres (Mollusca, Aplacophora) from the South China Sea and paraphyly of Proneomeniidae Simroth, 1893

M. Carmen Cobo https://orcid.org/0000-0002-8481-2086 A * , Emily L. McLaughlin https://orcid.org/0009-0006-0297-2067 A and Kevin M. Kocot https://orcid.org/0000-0002-8673-2688 A B
+ Author Affiliations
- Author Affiliations

A Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, USA.

B Alabama Museum of Natural History, The University of Alabama, Tuscaloosa, AL, USA.

* Correspondence to: mcobollovo@ua.edu

Handling Editor: Nerida Wilson

Invertebrate Systematics 37(6) 301-333 https://doi.org/10.1071/IS22062
Submitted: 22 November 2022  Accepted: 14 April 2023   Published: 29 May 2023

© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing.

Abstract

Solenogastres and Caudofoveata (Aplacophora) remain some of the least known molluscs, despite ubiquity in the marine environment and importance in understanding molluscan evolution. The use of new morphological techniques and development of DNA barcode libraries have helped make specimen identification easier. However, for solenogasters, using histology for identification and adequate description of species remains necessary in most cases. This, together with the facts that knowledge about solenogaster species distributions is biased and that most species were described from one or very few individuals, explains why many open questions about the actual distribution, intra- and interspecific variability, etc., remain. We performed an integrative taxonomic study of eight specimens of solenogasters from the South China Sea (West Pacific Ocean) thatresulted in the identification of four new species of Proneomeniidae. Species identification and description following the established diagnostic characters were straightforward. However, phylogenetic analysis of molecular data obtained from these specimens and other members of Proneomeniidae indicate that the family is polyphyletic. We recovered representatives of two other families, Epimeniidae (Epimenia) and Strophomeniidae (Anamenia), nested within Proneomeniidae with strong support. Ancestral character state reconstruction indicates that characters commonly used in solenogaster taxonomy, such as the radula and foregut glands, may be more evolutionarily labile in this group than previously known. Therefore our work fills knowledge gaps regarding the diversity and distribution of members of this family but raises important questions about solenogaster taxonomy and systematics that should be further assessed with additional markers and broader taxon sampling.

ZooBank: urn:lsid:zoobank.org:pub:BCADACD6-9AD0-442A-AD64-031BA8D88599

Keywords: barcoding, biodiversity, mitochondrial DNA, Mollusca, morphology, south-west Pacific, systematics, taxonomy.


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