Gastropteron viride Tokioka & Baba , 1964

Description

A tiny gastropterid 3.5 mm long, based on a single specimen. The animal is so strongly contracted in alcohol that the exact parapodial shape cannot be confirmed; when both parapodia are extended the animal is a little wider than long, and each parapodium is nearly as wide as the dorsal hump. The head does not protrude. The dorsal hump is oval, longer than wide, with a short club-shaped protuberance on the midline at its posterior end. The free mantle margin is very long, extending from the right anterior corner of the dorsal hump to the posterior median protuberance and forming a narrow flange. Ctenidium with eight leaflets.

Living colour: the upper surface of the parapodia is greenish, fringed with a white margin; two bright red patches lie along the periphery of each parapodium. The dorsal hump is yellowish, with a white patch near the centre and a large red patch slightly posterior to it; the posterior median protuberance is red. The cephalic shield is yellowish and bears a red colour pattern in the form of a Lorraine Cross near the posterior edge. About 750 eggs (180-210 μm, reddish-orange in life) were laid in captivity.

Distribution

Known from a single specimen. Type locality: Kannontuka-dasi of Amadaiba in Sagami Bay, Japan, 70 m.

Etymology

The specific epithet viride is the neuter of Latin viridis ("green"), in reference to the general greenish colour of the parapodia.

Remarks

The description rests on a single specimen, and the original authors flagged the bifurcated tail and the questionable existence of a mantle aperture as anatomical uncertainties.

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References

• Gastropteron viride n.sp., Tokioka T. & Baba K. (1964). FOUR NEW SPECIES AND A NEW GENUS OF THE FAMILY GASTROPTERIDAE FROM JAPAN (GASTROPODA : OPISTHOBRANCHIA). Publications of the Seto Marine Biological Laboratory. 12(3): 201-229. https://doi.org/10.5134/175366