Last November, Sophia Ratcliffe, Technical & Data Partner Support Officer at the NBN received an email from Dr. Manuel Caballer Gutierrez of the Muséum National d’Histoire Naturelle, France. The email related to the possible discovery of the sacoglossan opisthobranch mollusc Hermaea cantabra in the UK.
Dr. Caballer had seen an image on the NBN Atlas labelled as Hermaea bifida, which he thought was Hermaea cantabra, a species he had previously authored in 2015. It was a species thought to be endemic to the Bay of Biscay, the type location being Santander, Spain.
The image on the NBN Atlas had been provided by David Fenwick who produces the website APHOTOMARINE, and who has kindly supplied 2,000 species images for use within the NBN Atlas.
On receiving the email, Sophia put Dr. Caballer and David in touch with one another. Subsequently, David supplied a higher resolution image, showing the full detail of the Hermaea in question. From this Dr. Caballer was able to confirm that the species was indeed Hermaea cantabra.
This important discovery has also allowed Chris Raper at the UK Species Inventory to add the species to the UK list. This means that the species name and image will be correctly cited on the NBN Atlas as soon as possible.
Further work
Dr. Caballer later examined all of David’s Hermaea images, but was unfortunately only able to identify the species in three of seven small image sets. Only one set was found to be of H. bifida (considered native and our only representative of the genus), but two sets were of the new H. cantabra. The first record of H. cantabra in the UK was found to be from The Lizard, Cornwall, a single specimen found in a small sample collected from the shallow sublittoral, 25.09.14. The second record was from Marazion, Cornwall, with six H. cantabra being found in a sample of algae taken from a lower shore pool, 22.05.15. Both samples contained the red algae Ceramium on which the species is known to feed, the species is also known to feed on the green algae Codium, especially on Codium tomentosum.
The only H. bifida identified was an individual found in a sample of algae taken from a lower shore pool at Penzance, Cornwall, 08.01.15. The sample contained the algae, Halurus flosculosus, Mrs. Griffiths’s Little Flower, which is likely to be the species the specimen was feeding on. This confirmed that both H. cantabra and H. bifida can be found at intertidal sites in Mounts Bay, Cornwall. This shows the importance of taking care when identifying Hermaea in UK waters, especially as David feels that those who sample algae for the purpose of identification at home are most likely to come across either one of these species given how well they camouflage on their food.
More new species
H. cantabra is the latest of a number of marine species new to the UK that David has found in the far west of Cornwall, of southern origin. These species include the nemerteans Lineus grubei, Vieitezia luzmurubeae and Nemertopsis bivittata, but also include un-described polychaete worms and nudibranchs, which are still being investigated. Please watch this space!
References:
CABALLER, M. and ORTEA J. A. “New data on the genus Hermaea (Mollusca: Sacoglossa) in Europe, with the description of a new species from Spain“.
Article written in conjunction with David Fenwick. David is a past winner of the David Robertson Adult Award for biological recording in the marine environment .