Molecular phylogeny of the genus Dorometra Clark, 1917 (Crinoidea: Comatulida: Antedonidae): a new genus and new insights for future taxonomic revisions of Antedonidae

Abstract

Dorometra Clark, 1917 (Comatulida: Antedonidae) is an Indo-Pacific genus of small-sized cryptic feather stars currently comprising nine species. The monophyly of this crinoid genus has been widely questioned, although only few studies have investigated the phylogeny of Antedonidae in depth. In this study we used an integrated approach combining molecular phylogenetic, morphology, and multivariate analyses to clarify the taxonomic placement of the genus Dorometra within family Antedonidae. Eight of the nine known species of the genus collected from Australia to the Sea of Japan were included in analyses. Phylogenetic analyses using sequences from two mitochondrial (COI, 16S) and one nuclear (28S) genes demonstrate that Dorometra is polyphyletic, and its species are divided into three main clades, which are spread within other Antedonidae. As a result, we herein describe Nesometra gen. nov. Four different species delimitation methods on single and multi-locus alignments also showed higher diversity than previously thought. In particular, our results highlighted the presence of cryptic diversity within the species Dorometra nana (Hartlaub, 1890) in geographically close localities within southern Japan. By multivariate analysis of morphological matrix, we confirmed the homoplasy and plasticity of the taxonomic characters used in the description of Dorometra species, providing a path forward for the general taxonomic revision of this genus and of Antedonidae and related families.

http://zoobank.org/urn:lsid:zoobank.org:pub:DB7C239C-5CA0-485B-B4A8-205288FC4080

Key words:

• coral reefs
• crinoids
• cryptic diversity
• echinoderms
• Okinawa
• phylogeny
• Ryukyu Islands
• species delimitation

Acknowledgements

The authors thank Dr M. Eléaume (MNHN, Paris) for providing unpublished sequences of D. clymene. The authors would like to thank the following collection curators who helped us to obtain and examine voucher materials: Dr J. Bleeker (Naturalis, Leiden), G. Dally (MGNT, Darwin), Dr S. Ishida (OMNH, Osaka), C. Rowley (MV, Melbourne), M. Shimabukuro and and T. Sasaki (RUMF, Ryukyu University Museum (Fujukan). We thank the following people for providing additional bibliographical and photographic material: J. Ablett (NHM, London), Dr L. Carsten (Leibniz Institute for Evolution and Biodiversity Science), W. Crawford (Western Australian Museum Library), P. Fiorentino (SZN, Naples) and B. Hays (NOVA Southeastern University). We would also like to thank Dr Y. Fujita (Okinawa Prefectural University of Arts), Dr M. Mizuyama (U. Ryukyus), Dr M. Obuchi (Endo Shell Museum of Manazuru, Kanagawa) and F. Sodeyama (JAMSTEC) for kindly providing expertise and advice during this research. The following people are thanked for invaluable help in fieldwork, sampling and logistics: Dr P. Biondi, F. Clementoni, L.C.J. Fourreau, Dr G. D. Masucci, Dr H. Kise, Dr Y. Kushida, Dr K. Soong, Dr H.B. Wee, and all other MISE members, as well as Dr T. Fujii (Kagoshima U.). We thank the Università Politecnica delle Marche (Erasmus Campus World scholarship) and the Systematics Research Fund (SRF 2020/2021, Systematics Association) for funding support to RV. AP is thankful to JSPS for financial support (18F18755). We would like to thank four anonymous reviewers for improving the quality of the manuscript.

Supplemental material

Supplemental material for this article can be accessed here: https://dx.doi.org/10.1080/14772000.2023.2192209.

Associate Editor: Dr Xikun Song