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RESEARCH ARTICLE

Molecular systematics of Thouarella (Octocorallia : Primnoidae) with the description of three new species from the Southern Ocean based on combined molecular and morphological evidence

Mónica Núñez-Flores https://orcid.org/0000-0002-9692-1909 A B C D , Daniel Gomez-Uchida B and Pablo J. López-González C
+ Author Affiliations
- Author Affiliations

A Programa de Doctorado en Sistemática y Biodiversidad, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepcion, Victor Lamas, 1290, 4070386, Chile.

B Genomics in Ecology, Evolution and Conservation Lab (GEECLAB), Department of Zoology, Facultad de Ciencias Naturales y Oceanográficas & Núcleo Milenio INVASAL, Universidad de Concepción, Concepcion, Victor Lamas, 1290, 4070386, Chile.

C Biodiversidad y Ecología Acuática (BECA), Departamento de Zoología, Facultad de Biología, Universidad de Sevilla, avenue Reina Mercedes, 6, E-41012 Seville, Spain.

D Corresponding author. Email: nuez.monica@gmail.com

Invertebrate Systematics 35(6) 655-674 https://doi.org/10.1071/IS20078
Submitted: 30 October 2020  Accepted: 13 January 2021   Published: 13 August 2021

Abstract

Thouarella Gray, 1870, is one of the most speciose genera among gorgonians of the family Primnoidae (Cnidaria : Octocorallia : Anthozoa), being remarkably diverse in the Antarctic and sub-Antarctic seafloor. However, their diversity in the Southern Ocean is likely underestimated. Phylogenetic analyses of mitochondrial and nuclear DNA markers were integrated with species delimitation approaches as well as morphological colonial and polyps features and skeletal SEM examinations to describe and illustrate three new species within Thouarella, from the Weddell Sea, Southern Ocean: T. amundseni sp. nov., T. dolichoespinosa sp. nov. and T. pseudoislai sp. nov. Our species delimitation results suggest, for the first time, the potential presence of Antarctic and sub-Antarctic cryptic species of primnoids, based on the likely presence of sibling species within T. undulata and T. crenelata. With the three new species here described, the global diversity of Thouarella has increased to 41 species, 15 of which are endemic to the Antarctic and sub-Antarctic waters. Consequently, our results provide new steps for uncovering the shelf benthonic macrofauna’s hidden diversity in the Southern Ocean. Finally, we recommend using an integrative taxonomic framework in this group of organisms and species delimitation approaches because the distinctions between some Thouarella species based only on a superficial examination of their macro- and micromorphological features is, in many cases, limited.

Keywords: Antarctic marine biodiversity, integrative taxonomy, species delimitation, Weddell Sea.


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