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Author: Ekimova, Deart, Antokhina, Mikhlina & Schepetov, 2022
Order: Nudibranchia Family: Flabellinidae
Maximum Size: 25 mm
Sightings: Sunshine Coast
Coryphellina aurora Ekimova, Deart, Antokhina, Mikhlina & Schepetov, 2022
Coryphellina O’Donoghue, 1929, was re-erected (from synonymy, first with Coryphella and latterly Flabellina) by Korshunova et al, 2017 thus making Coryphellina rubrolineata O’Donoghue, 1929 the Type Species. Phylogenetic and morphological investigations of a number of specimens collected in Vietnam waters (Ekimoiva et al, 2022) found several cryptic species previously all lumped into Coryphellina rubrolineata. Additionally the findings have confirmed that Coryphellina rubrolineata rather than being a widespread tropical species is actually confined to its type locality and adjacent waters – Red Sea and Arabian Sea but also introduced into the Mediterranean Sea.
A medium sized (~27 mm) but typical aeolid form with slender body and foot. Anterior foot corners well-developed – tentacular. Oral tentacles 1.5 times rhinophore length and with tapered tips. Rhinophores are highly papillate on the posterior face and bear pointed tips. There are up to 9 ceratal groups on each side (in those so far examined) – first group largest and quite large, second and subsequent located posterior to the inter-hepatic space. Cerata on elevations (pedunculate), cylindrical, elongated and pointed. Tail short, quickly tapering following posterior-most ceratal group.
– Background (body and notum): Translucent magenta.
– Oral tentacles: Translucent magenta gradually increasing in intensity distally. Tips are translucent but sparsely covered in fine white specks.
– Rhinophores: Magenta to pink with orange papillae and translucent tip.
– Cerata: Translucent light magenta not unlike body colour. Dark magenta to almost red subapical band that bleeds into a whitish section below. Orange tips, sometimes with white spot. Digestive diverticulum mostly visible, brown colouration.
– Mid-dorsal line: Only present on head between rhinophores, thin to indistinct, light magenta to pink.
– Lateral lines: Absent
It can be seen that there is variability in colour and also in the intensity of colours. The significant external features assisting delineation from its near relatives is the almost complete absence of a mid-dorsal line (apart from indistinct remnant on head region between rhinophores, when present) and complete absence of lateral lines. The larger number of ceratal groups and the large number of cerata in the first group are also helpful diagnostic features.
Care should be exercised in making comparisons as only one specimen was examined and illustrated for the description.
Note on Coryphellina:
As mentioned above, Coryphellina O’Donoghue, 1929, was re-erected by Korshunova et al, 2017. Since then its use has become frequent despite reservations from some taxonomists who cite that: some taxa were omitted, paraphyly was simply transferred and sampling was insufficient. Ekimova et al, 2022 conducted further molecular testing and subsequently identified and described four new closely related cryptic species and two putative species of Coryphellina. In order to stay in step with most common usage we are now using Coryphellina. There is no doubt that there is a clade involved. There is also no doubt there were issues of paraphyly in Flabellina previously and the splitting into additional genera such as Samla and Coryphellina may not entirely solve that issue, however, given the current usage (>4 years), it may be more confusing not to make the change at this point. Once larger sampling across more geolocations is undertaken a clearer picture may be resolved.
David A. Mullins – May 2022
– Gosliner, T. M. & Willan, R. C. (1991). Review of the Flabellinidae (Nudibranchia: Aeolidacea) from the tropical Indo–Pacific, with descriptions of five new species. Veliger, 34, 97–133.
– Schulze, A. & Wägele, H. (1998). Morphology, anatomy and histology of Flabellina affinis (Gmelin, 1791) (Nudibranchia, Aeolidoidea, Flabellinidae) and its relation to other Mediterranean Flabellina species. Journal of Molluscan Studies 64: 195–214.
– Yonow, N. (2008). Sea Slugs of the Red Sea. Pensoft Publishers.
– Furfaro, G., Salvi, D., Mancini, E. & Mariottini, P. (2017 Online). A multilocus view on Mediterranean aeolid nudibranchs (Mollusca): Systematics and cryptic diversity of Flabellinidae and Piseinotecidae. Molecular Phylogenetics & Evolution, 118, 13–22.
– Korshunova, T., Martynov, A., Bakken, T., Evertsen, J., Fletcher, K., Mudianta, I. W., Saito, H., Lundin, K., Schroedl, M. & Picton, B. (2017). Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: Aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda). ZooKeys 2017, 717, 1.
– Gosliner, T. M., Valde ́s, A ́. & Behrens, D. W. (2018). Nudibranch & Sea Slug Identification – Indo-Pacific, 2nd Edition. New World Publications, Jacksonville, Florida, USA.
– Ekimova, I., Deart, Y., Antokhina, T., Mikhlina, A. & Schepetov, D. (2022). Stripes Matter: Integrative Systematics of Coryphellina rubrolineata Species Complex (Gastropoda: Nudibranchia) from Vietnam. Diversity,14,294.