Pinufius rebus Er. Marcus & Ev. Marcus, 1960

Description

A small aeolid nudibranch reaching about 10 mm in length. The body is oval, with a translucent brown background colour covered uniformly across the dorsum by dense, short cerata. Each ceras swells slightly in the middle and ends in a rounded tip. The mid-dorsal ridge and a pair of lateral ridges are present but largely concealed by the dense cerata. The rhinophores are smooth and translucent brown.

Distribution

Originally described from material collected in the Red Sea and the Maldive Islands. Subsequently recorded broadly across the Indo-West Pacific coral-reef belt, with sightings from Australia, the Philippines, Japan and the Marshall Islands.

Etymology

The specific epithet rebus is Latin for "by things" or "in the form of a riddle". The original description does not explicitly explain the name, but the combination of Pinufius and rebus is generally read as a playful coinage.

Remarks

Feeds on the tissues of stony corals of the genus Porites, on which it lives. The translucent brown colouration and the dense cover of short cerata are interpreted as visual mimicry of Porites polyps.

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References

• Pinufius rebus n. g. n. sp., Marcus Er. & Marcus Ev. (1960). Opisthobranchia aus dem Roten Meer und von den Malediven. Abhandlungen der Akademie der Wissenschaften und der Literatur in Mainz. Mathematisch-naturwissenschaftliche Klasse. 12: 873-934.
• アワユキウミウシ（新称）, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
• Pinufius rebus (= Tenellia rebus syn. nov.), Fritts-Penniman A.L., Gosliner T.M., Mahardika G.N. & Barber P.H. (2020). Cryptic ecological and geographic diversification in coral-associated nudibranchs. Molecular Phylogenetics and Evolution. 144: 106698. https://doi.org/10.1016/j.ympev.2019.106698