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Coryphellina pseudolotos

Species Profile

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Coryphellina pseudolotos

Author: Ekimova, Deart,  Antokhina, Mikhlina & Schepetov, 2022

Order: Nudibranchia  Family: Flabellinidae

Maximum Size: 20 mm

Sightings: Sunshine Coast


Coryphellina pseudolotos 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, and wherein they described Coryphellina lotos. At the time its discontinuous dorsal and lateral lines made for easy identification. A sister species, Coryphellina pseudolotos, was described by Ekimova et al, 2022 (also redescribing Coryphellina lotos) that has an identical external morphological presentation and overlapping colour variations making delineation most difficult. These two are the only species of the Coryphellina genus where the dorsal and lateral lines are discontinuous (see below). The re-erection made 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 including this one. 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.

Typical aeolid form with slender body and foot. Anterior foot corners well-developed – tentacular. Oral tentacles 2 times rhinophore length and with tapered tips. Rhinophores are highly papillate on the posterior face and bear pointed tips. There are up to 6 ceratal groups on each side – first group largest, second and subsequent located posterior to the inter-hepatic space. Cerata on elevations (slight pedunculate), cylindrical, elongated and pointed. Tail short, quickly tapering following posterior-most ceratal group.

– Background (body and notum): Translucent.
– Oral tentacles: Translucent proximal third, magenta or dark-pink wide band subapically, white or translucent tip.
– Rhinophores: Translucent or very light orange with magenta sub-apical band and translucent tips.
– Cerata: Translucent, same as body, magenta subapical band varying in intensity with white or pastel orange tip. Digestive diverticulum visible, light-orange.
– Mid-dorsal line: Discontinuous, may be faint on body – pink to magenta in colour. (Many Sunshine Coast species we have recorded present with their interrupted mid-dorsal line as quite distinct.)
– Lateral lines: Discontinuous. Located just below notal edge and in regions between ceratal clusters – pink to magenta in colour.

It can be seen that there is variability in colour and also in the intensity of colours. This species is difficult to delineate from Coryphellina lotos using external characteristics and colouration. Both are the only described species of Coryphellina exhibiting discontinuous lines. Large specimens (~20 mm), that are also translucent, are more likely Coryphellina pseudolotos. In reading the descriptions and reviewing the images supplied therein it may be deduced that Coryphellina pseudolotos has a translucent body without white or purple tint at any size. However, there is some conflict in the descriptions by Ekimova et al, 2022 concerning the comparison of these two species. On the one hand C. pseuodolotos is described as having a maximum length of 15 mm but in the Remarks paragraph there is a reference to specimens ~20 mm retaining their translucent appearance.

Formerly listed on this site as Flabellina lotos.

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.

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