Atlantic West Ophiothrix spp. in the scope of integrative taxonomy: Confirming the existence of Ophiothrix trindadensis Tommasi, 1970

Abstract

We re-describe and confirm the validity of Ophiothrix trindadensis Tommasi, 1970 (Echinodermata: Ophiuroidea). This is a native species from Brazil, however it lacked a type series deposited in scientific collections. The recognition of O. trindadensis was made possible using integrative taxonomy applied to many specimens from the type locality (Trindade Island) as well as from different locations along the Brazilian coast (Araçá Bay and Estuarine Complex of Paranaguá). Initially, 835 specimens were studied and divided into four candidate species (CS) inferred from external morphological characters. Afterwards, the CSs were compared using integrative taxonomy based on external morphology, arm microstructures morphology (arm ossicle), morphometry, and molecular studies (fragments of the mitochondrial genes 16S and COI). Analyses indicated CS1 and CS2 as O. trindadensis, and CS3 as O. angulata, both valid species. CS4 remains O. cf. angulata as more data, including their ecology and physiology, are needed to be definitively clarified. Our integrative investigation using specimens from the type locality overcame the lack of type specimens and increased the reliable identification of O. trindadensis and O. angulata.

Catalogue of living crinoids (Echinodermata: Crinoidea) from Brazil

“…It is notable that over the last decade, the number of studies on Brazilian echinoderms has increased significantly and has included publication of several papers on different classes (e.g., Alitto et al 2019;Barbosa et al 2015;Contins & Ventura 2011;Gondim et al 2013Gondim et al , 2014Gondim et al , 2018Lopes et al 2016;Martins & Souto 2020;Moura et al 2015;Tavares et al 2019) and the appearance of new specialists. However, this has not applied to Crinoidea.…”

Unravelling the taxonomic identity ofOphiothelaVerrill, 1867 (Ophiuroidea) along the Brazilian coast

“…danae from the type series shows that these species did not totally overlap on the LDA. Morphometry has been used as a powerful tool for delimiting species, particularly when applied with an integrative approach (Arribas et al ., 2013; Marinho et al ., 2017; Di Camillo et al ., 2018; Alitto et al ., 2019). In the case of O .…”

“…On the other hand, the level of genetic divergence between some five-armed specimens from NW Australia identified as O. vincula and six-armed O. danae from the eastern Pacific was 0.3–0.7% and 1.4–2.7% for 16S and COI, respectively. These COI divergence rates are higher than those found within Ophiothrix trindadensis (~1.5%) (Alitto et al ., 2019). Therefore, future studies should investigate if O. vincula should be recognized as a distinct species, or just a five-armed variant of O. danae .…”

New diagnostic characters forAmphiodiaandOphiophragmus(Amphiuridae, Ophiuroidea, Echinodermata)

“…This demonstrates the power of morphometry for taxonomic studies and highlights the characters that should be considered in diagnoses. We emphasize the use of morphometry as a powerful tool particularly when applied with an integrative approach (Arribas et al ., 2013; Alitto et al ., 2019). Probably the species not well separated in the LDA are related to the low number of specimens due to the difficulties with collecting them.…”

“…Recently, all brittle star families were diagnosed using external morphology and microstructure of ossicles (O'Hara et al ., 2018). The morphometry of diagnostic structures has also been used as a powerful tool for delimiting species, particularly when included in an integrated approach (Arribas et al ., 2013; Alitto et al ., 2019). This methodology demonstrates how different disciplines can be more informative when treated together (Stöhr, 2012), providing taxonomy with a more integrated view, and consequently, improving our knowledge.…”