Polycera tricolor Robilliard, 1971

What is the three-coloured polycera?

The three-coloured polycera (Polycera tricolor) is a small translucent bluish-white nudibranch of the northeastern Pacific, its appendages, rhinophores and gills each marked with a black base, a yellow band and a white tip.

Description

A small polycerid nudibranch reaching about 2 cm. The body is translucent bluish-white. Along the front of the head are five to eleven finger-like appendages, and around the gills are four to six more; these, together with the rhinophores and gills, are three-coloured — black at the base, with a yellow band and a white tip. A yellow line runs down the midline of the back to the tail tip, and a yellow line sometimes rims the edge of the foot.

Distribution

Occurs in the northeastern Pacific from British Columbia (and southern Alaska) to Baja California, Mexico, mainly on exposed coasts, down to about 60 m.

Etymology

The specific epithet tricolor is Latin for "three-coloured", after the black, yellow and white banding of its appendages, rhinophores and gills.

Remarks

Like other members of the genus Polycera, it feeds on bryozoans.

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References

• Polycera tricolor n.sp., Robilliard G.A. (1971). A new species of Polycera (Opisthobranchia: Mollusca) from the northeastern Pacific, with notes on other species. Syesis. 4: 235-243.
• Polycera tricolor, Behrens D.W., Hermosillo A., Fletcher K. & Jensen G.C. (2022). Nudibranchs & Sea Slugs of the Eastern Pacific. Molamarine.