Author Interview: Integrative species delimitation in the common ophiuroid Ophiothrix angulata

PeerJ spoke to Yoalli Quetzalli Hernández-Díaz about the recently published PeerJ Life & Environment article Integrative species delimitation in the common ophiuroid Ophiothrix angulata (Echinodermata: Ophiuroidea): insights from COI, ITS2, arm coloration, and geometric morphometrics. The article was published as part of the IABO Hub. The IABO Hub is the publishing home of the International Association for Biological Oceanography, and features the latest biological oceanography research published by the members of IABO.

Creidt: Invertebrate Zoology Collection, Florida Museum of Natural History, University of Florida, and Y. Quetzalli Hernández-Díaz.

Y. Quetzalli Hernández-Díaz Collecting Ophiuroids

Can you tell us a bit about yourself?

Hello, I am finishing my Ph.D. and I have been working with benthic marine invertebrates for several years. This time, I had the incredible opportunity to work with my first love—echinoderms. Among echinoderms, the group of ophiuroids (brittle stars) has always fascinated me with their captivating beauty and intriguing nature. My Ph.D. research occurred between Mexico City, Florida, and the Yucatan Peninsula, where I delved into the taxonomic complexities of a well-known species in this region with enormous phenotypic plasticity. I invite you to explore our work and discover more about our findings!

Can you briefly explain the research you published in PeerJ?

We tried to unravel the genetic relationship between the various shapes and colorations of the arm in the ophiuroid species Ophiothrix angulata. This species is widely distributed across different latitudes and depths, and its classification has caused confusion since its description almost 200 years ago due to the great variety of colorations and subtle differences observed, which have confused alpha taxonomists who have relied solely on morphological characteristics. So, to address this taxonomic challenge, we adopted an integrative approach, conducting separate analyses on multiple types of genetic and morphological data before combining them. By compiling extensive evidence and adhering to species definition criteria, we have determined that Ophiothrix angulata represents a species complex with cryptic diversity more or less delimited within large geographic regions. Undertaking this task was undeniably challenging yet equally exhilarating.

What did you discover and where?

We have made significant discoveries regarding the species Ophiothrix angulata, which has been traditionally recognized as a single species. In the northwestern Atlantic distribution, we have identified two distinct genetic clades using the COI (mitochondrial) and ITS2 (nuclear) genetic markers. Notably, this genetic differentiation aligns with the variations observed in the shape of the ventral and dorsal arm plates. By combining genetic and morphometric data through integrative analyses, we have gathered substantial evidence to support the existence of more than one species within the cryptic complex of Ophiothrix angulata. One of these genetic clades reveals that a group previously classified as O. angulata belongs to a newly ophiuroid species. Additionally, an exhaustive analysis of the arm coloration patterns has provided scientific evidence indicating that coloration alone is not a reliable morphological characteristic for distinguishing the different genetic clades within our study. This finding holds great significance for the O. angulata species complex, as it challenges the validity of subspecies that were described solely based on coloration patterns in the 19th century, which remain relevant today.

How did you first hear about PeerJ, and what persuaded you to submit to us?

A few years ago, I became acquainted with PeerJ and was immediately drawn to its unique qualities—an engaging and interactive interface. Since then, due to its swift publication process, I have contemplated submitting my Ph.D. work to this journal. Nevertheless, a call from the International Association for Biological Oceanography Hub, which a fellow researcher shared with me, provided the impetus to finalize and submit the article promptly.

How was your experience publishing an article in the IABO hub?

PeerJ and IABO Hub stand out for their user-friendly platform and remarkable professionalism and dedication to the scientific community. The experience of working with IABO Hub has been exceptional, I sincerely thank you for opening this call and extending this valuable opportunity to showcase our research.