Mia (left), Aletta, (middle) and Michaela (right) at their graduation ceremony in December 2023

Sometimes, it also requires returning to the specimen itself; measuring fins, examining skin structures, counting microscopic features, and asking whether these physical features tell the same story as the genetic code.

This was the focus of a recent research visit by PhD candidate Mia Groeneveld and postdoctoral researcher Dr Michaela van Staden to the South African Institute for Aquatic Biodiversity in Makhanda, Eastern Cape. Both researchers are part of the Shark and Ray Research Group, led by Prof Aletta Bester-van der Merwe, where genetic and genomic tools are used to support the conservation and management of sharks and rays.

The visit formed part of an ongoing effort to better understand guitarfishes of the genus Acroteriobatus; a group of threatened rays whose taxonomy and species boundaries have long been complicated by overlapping physical features and historical misidentifications. For threatened marine species, these uncertainties matter. If species are poorly defined, it becomes much harder to assess their conservation status, monitor their populations, or manage them effectively. 

At South African Institute for Aquatic Biodiversity (SAIAB), Groeneveld and van Staden spent a week working through museum specimens under the guidance of Dr David Ebert, a world-renowned elasmobranch taxonomist known for his extensive work on sharks and rays. Their work involved detailed morphometric and meristic assessments, including measurements of pectoral, dorsal, caudal, and pelvic fins, as well as microscopic examination of dermal denticles and nasal lamellae. These small anatomical details may appear subtle, but they are often critical in distinguishing closely related species.

Guitarfish nasal lamellae under the microscope

For the Shark and Ray Research Group, this work builds directly on their recent publication in Marine Biodiversity, which investigated the molecular taxonomy of the guitarfish genus Acroteriobatus. Their study used DNA sequence data to assess molecular operational taxonomic units in an attempt to resolve species boundaries. While DNA can reveal hidden patterns of species relatedness, taxonomy is strongest when molecular evidence is examined alongside morphology. In this case, the SAIAB visit helped bridge that gap by linking genetic findings to preserved specimens, the physical material on which species descriptions, identifications, and future taxonomic decisions ultimately depend.

Ventral view of a preserved guitarfish specimen

Beyond the technical work, the visit also reflects a broader goal of the Shark and Ray Research Group: to create opportunities for early-career researchers to build specialist skills, develop international networks, and contribute meaningfully to marine biodiversity research. For a department grounded in genetics, the project also shows the value of looking across disciplines. In this case, the story of species conservation is written not only in DNA, but also in the shape of a fin, the texture of a denticle, and the careful examination of specimens preserved for future science.