Parasites from an Endangered Deep-Water Shark and their link to Professor Sir E. Ray Lankester FRS, pioneer of Marine Conservation.
By ucwehlc, on 5 June 2023
The Grant Museum is currently closed this summer for some refurbishment works but we still have plenty of exciting stories to tell from the collection.
Today’s blog is by visiting researcher Dr Andrew McCarthy from Canterbury College, UK.
Initially this short piece was planned to be solely about the identification of specimens of an intestinal parasite of an endangered species of deep-water shark Echinorhinus brucus, the Bramble Shark, from the collections of the museum.
However, by strange coincidence as will be explained, it is being written on the day that the United Nations in New York announced in its new global marine biodiversity conservation initiative “The High Seas Treaty”. Embracing almost two thirds of the World’s oceans that lie outside national boundaries the treaty provides a legal framework for the establishment of vast Marine Protected Areas (MPA’s) to protect against loss of marine biodiversity. The coincidence is that the specimens under discussion here are thought, ultimately, to have their origin associated with the work of a British pioneer of marine conservation of well over one hundred years ago. He was namely Professor Sir Edwin Ray Lankester FRS, a past Director of the Grant Museum of Zoology and Comparative Anatomy (1874-1890), Jodrell Professor of Zoology and Comparative Anatomy at University College London, and Linacre Professor of Comparative Anatomy at the University of Oxford. A larger-than-life figure, some believe him to be one of the inspirations for Sir Arthur Conan Doyle’s Professor Challenger of “The Lost World”.
Lankester, time has proved, was a man of extraordinary foresight in his realisation that the oceans were not an inexhaustible resource for limitless exploitation by humans (particularly regarding fish stocks), but were much more fragile than that, and that they deserved scientific study and, above all, protection. He carried forward his ideas at both scientific and political levels in the face of formidable opposition from such academic heavyweights of the time as T.H. Huxley, or “Darwin’s Bulldog” as he was known. One of Lankester’s major achievements was his founding of the Marine Biological Association in 1884 and further the creation of the Plymouth Marine Laboratory, an institution dedicated to the study and conservation of marine life, an excellent facility of which I have fond memories of visiting in the early 1990’s as a NERC Post-Doctoral Research Fellow working on cestode parasites of marine rays. The Plymouth Marine Laboratory is the probable origin of our shark parasite specimens.
Specimen D229 is catalogued in the Grant Museum of Zoology collection as “Distoma sp.” “fluid preserved specimen from “Echinorhinus spinosus” (= E. brucus, the Bramble Shark) from “Plymouth (Devon, England)”, a single specimen jar containing two worms approximately 5cm and 8 cm in length. As a visiting researcher in parasitology the term “Distoma” is always interesting to see in a museum catalogue since it is a very old taxonomic term that used to be applied to all trematodes, or flukes as they are commonly known, (Di=two, stoma = opening (sucker)). Very often, until you see the specimen you do not know what you have; it could be a common species, but it may equally be something rare, or even a species new to science. In this case the data label on the specimen jar bore the name Distomum insigne a species of parasitic helminth worm, a trematode in this case, listed by Diesing in 1850 in his Systema Helminthum Vol 1. (Vindobonae/Vienna) ; a renaming of Distoma scimna of Risso who recorded it in 1826 from E. spinosus (= brucus) probably from the Mediterranean, at Nice where he lived and worked.
The species is now known as Otodistomum veliporum, it having been described under the name Distoma veliporum by Creplin in 1837 from the stomach of the shark Hexanchus griseus, the Bluntnose Six-gill Shark, from the Mediterranean Sea at Sicily. Examination of the two fluid preserved specimens from the museum showed that they are clearly of the genus Otodistomum (Trematoda: Azygiidae) and it would seem that this is the first report of the genus from E. brucus, in British waters. It is most probable that the specimens are O. veliporum since this species seems to be specific to hexanchiform, squaliform and squatiniform sharks, and torpedoes. A closely related and morphologically similar species O. cestoides is parasitic in rays and some small squaliform sharks.
The Bramble Shark (E. brucus) is now sadly classified by the IUCN as an endangered species in British and European waters, a situation probably brought about by overfishing, and data deficient elsewhere in the World. As such any existing material of both the shark itself and its parasite fauna is extremely important since removal of specimens from the wild for study would now clearly be unjustifiable. However, we know that parasites themselves are important components of global biodiversity, important factors in the maintenance of ecosystem health, and that knowledge of parasite faunas of threatened species is important for conservation of both host and parasite. It is from well curated museum collections such as those of the Grant Museum of Zoology at University College London that such information may still be obtained. Lankester’s legacy of enabling the study of marine biodiversity, and its conservation, lives on.