Not All That Glitters Is Gold: Barcoding Effort Reveals Taxonomic Incongruences in Iconic Ross Sea Sea Stars

Abstract

The Southern Ocean is one of the most exposed regions to climate-related changes on our planet. Better understanding of the current biodiversity and past speciation events, as well as implementation of conservation actions and accurate identification of organisms to species level in this unique environment, is fundamental. In this study, two species of sea stars, Odontaster roseus Janosik & Halanych, 2010 and Odontaster pearsei Janosik & Halanych, 2010, are reported for the first time from the Terra Nova Bay area (TNB, Ross Sea, Antarctica) by using a combination of molecular (DNA barcoding) and morphological (coloration and skeletal features) analyses. Molecular results agree with external morphological characters of the two identified species, making occurrence in the area unequivocal. The two species were recently described from the Antarctic Peninsula, and went unnoticed for a long time in TNB, possibly having been confused with O. meridionalis (E.A. Smith, 1876), with which they share a bright yellow coloration. This latter species seems to be absent in the Ross Sea. Thus, the past literature referring to O. meridionalis in the Ross Sea should be treated with caution as these “yellow morphs” could be one of the two recently described species or even orange–yellow morphs of the red-colored congeneric O. validus Koehler, 1906. This work highlights the paucity of knowledge even in purportedly well-studied areas and in iconic Antarctic organisms.

Preliminary Assessment of Sea Star (Echinodermata, Asteroidea) Diversity in the Coastal Magellanic Region (South Chile) and Their Geographical Distribution

“…However, as Moreau et al (2021) pointed out, there seems to be a misidentification of the associated specimens, which was confirmed in our analysis (the sequences belong to Asterina fimbriata) [4]. Additionally, two other Odontaster species, Odontaster roseus and Odontaster pearsei, have been repeatedly misidentified as O. meridionalis [12]. Altogether, this questions the existence of O. meridionalis as a different species [12].…”

“…Additionally, two other Odontaster species, Odontaster roseus and Odontaster pearsei, have been repeatedly misidentified as O. meridionalis [12]. Altogether, this questions the existence of O. meridionalis as a different species [12].…”

“…Despite being a diversified and essential part of the Southern Ocean benthos, only scarce information is available regarding sea stars' diversity, evolution, and ecological roles [8]. Recent efforts have been made to increase sea star biodiversity knowledge in the Southern Ocean (e.g., [9][10][11][12]), including the Magellanic Region [8,[13][14][15]. However, the resulting estimations are inconsistent and often cover different geographical areas and depth ranges.…”

Planktonic, benthic and sympagic copepods collected from the desalination unit of Mario Zucchelli Research Station in Terra Nova Bay (Ross Sea, Antarctica).

“…Previous MNA contributions focused on Mollusca , Tanaidacea , Fungi , Ophiuroidea , Porifera , Bryozoa , Rotifera , Asteroidea and Copepoda ( Ghiglione et al 2013 , Piazza et al 2014 , Selbmann et al 2015 , Cecchetto et al 2017 , Ghiglione et al 2018 , Cecchetto et al 2019 , Bonello et al 2020 , Garlasché et al 2020 , Guzzi et al 2022 ). The special issue that included this publication contains additional articles that centre on specific marine animals, such as Holothurians (Guzzi et al, in prep.…”

Echinoids and Crinoids from Terra Nova Bay (Ross Sea) Based on a Reverse Taxonomy Approach

“…Taxonomic discrepancies, such as synonymous or cryptic species, are extremely common when a traditional taxonomic approach is used. Neither molecular nor morphological taxonomic methods are sufficient on their own [4] and the number of examples where this integrated approach is applied to identify species is rapidly increasing (sea stars (e.g., [5][6][7][8][9][10][11]), brittle stars (e.g., [12]), holothurians (e.g., [13]), fish (e.g., [14]) and many more.…”