Author: Innabi, Stout & Valdés, 2023

Order: Nudibranchia  Family: Discodorididae

Maximum Size: 25 mm

Sightings: Sunshine Coast

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Jorunna hervei Innabi, Stout & Valdés, 2023

A small and highly cryptic species of Discodorididae nudibranch.

The body of Jorunna hervei is covered in caryophyllidia and may be elongate and narrow when on the move to oval and flattened when at rest or feeding.  Colouration is grey to light brown that appears as numerous irregular dark patches being created by a close network of overlaid white pigment. This appearance, colour and pattern, matches closely the surface of its sponge prey such that it is cryptic in situ. The lamellate rhinophores, arising from low sheaths, are short but have distinct elongated apices. The gill, comprised of nine tripinnate branches that overlap and are held upright, also emerge from a plain low sheath. The arrangement of the gill can mimic somewhat the oscula of its host sponge.

The cream coloured spawn is laid on edge as a tight spiral of up to seven whorls, the free top edge being undulating.

Jorunna hervei is nearly always found upon its preferred sponge food.

Distribution is Western Pacific but may be limited. It is recorded from New Caledonia and Queensland & Northern NSW of Australia.

Previously known on this site as Jorunna sp. 02 – Changed 29/03/2023

David A. Mullins – March 2023

References:
– Camacho-García, Y. E. & Gosliner, T. M. (2008). Systematic revision of Jorunna Bergh, 1876 (Nudi- branchia: Discodorididae) with a morphological phylogenetic analysis. Journal of Molluscan Studies 74(2): 143–181.

– Hervé, J-F. (2010) Guide des Nudibranchs de Nouvelle-Calédonie et Autres Opisthobranches. Catherine Ledru, Nouméa, New Caledonia.

– Gosliner, T. M., Valde ́s, A ́. & Behrens, D. W. (2018). Nudibranch & Sea Slug Identification – Indo-Pacific, 2nd Edition. New World Publications, Jacksonville, Florida, USA.

– Innabi, J., Stout, C.C. & Valdés, A. (2023). Seven new “cryptic” species of Discodorididae (Mollusca, Gastropoda, Nudibranchia) from New Caledonia. ZooKeys 1152: 45–95.