Unveiling the world of parasites

CQUniversity’s Dr David Vaughan is shining a light on some of the world’s smallest and often overlooked creatures through new research into marine parasites. 

The fish parasite taxonomist, a biologist who specialises in the classification of organisms into groups on the basis of their structure and origin and behaviour, has described and illustrated new materials for a group of flatworms known as the Monogenea.

As a skilled illustrator, Dr Vaughan hand-draws the detailed sketches, which is a traditional method utilised by taxonomists. 

Dr Vaughan said creating a detailed identification of Monogenean characteristics plays an important role in understanding differences between species. 

“Monogeneans are generally ectoparasites, which means they live on the external surfaces of their hosts, typically fishes. I have a particular interest in those from sharks and stingrays,” Dr Vaughan explained. 

“They have a simple body structure, with a single attachment organ called the haptor that they use to attach to the host's body.

“Monogenean infections are a significant concern in aquaculture and fisheries industries as these parasites can cause various health issues in fish, including tissue damage, reduced growth, and increased susceptibility to other diseases.

“A greater body of knowledge around Monogenean biology and physical characteristics reveals a great deal more about where an organism belongs taxonomically and helps pinpoint new species. This can assist in developing strategies to control and manage monogenean infections in fish populations.”

In his most recent study, Dr Vaughan investigated a family of monogenean parasites known as Hexabothriidae, which includes representatives that typically infest the gills of sharks and rays.

“Globally, hexabothriids need more attention in terms of their classification,” he said.

“It is our goal to gather more information on this group, and others from sharks and rays, and to further explore their diversity and biogeograph.” 

Originally from South Africa, Dr Vaughan has been studying these parasitic worms for more than 15 years, with his recent findings taking place in his home country. 

He found five hexabothriid species from three different genera - Erpocotyle catenulata, Heteronchocotyle gymnurae, Hypanocotyle bullardi, Rajonchocotyle alba and Rajonchocotyle emarginata. 

“All of these species were previously not known from Southern Africa, and three of these hexabothriid species were recorded from new host species,” Dr Vaughan said.

“The discovery of these species in South Africa suggests that the same hexabothriid species are likely found in many parts of the world, not just in specific locations, and that they are not as particular about the hosts they infect as previously believed.”

Dr Vaughan hopes to extend his work to investigate monogeneans from Australia and New Zealand where he will train emerging research students in the art of monogenean taxonomy.