Acanthodoris pilosa

A more detailed account is available here: https://flic.kr/s/aHskD8TMGF

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Body

Up to 40mm long, exceptionally 55mm; high dome profile. Varies white, brown, black, or yellow (P. Lightfoot) https://flic.kr/p/oJLWhQ . Pale colours may be mottled or freckled darker. Soft, tall, thin, conical tubercles on mantle give shaggy appearance, but sometimes not well developed (J. Anderson) https://flic.kr/p/Aes3Cj .

Long rhinophores often bent and tilted outwards. About 7 voluminous gills, usually with opaque white along each side of midribs forming a star.

Key identification features

Acanthodoris pilosa

1: Soft, tall, thin, conical tubercles on mantle 6Ap flic.kr/p/Nrc9wu , but sometimes contracted/ poorly developed and not so distinctive (J. Anderson) flic.kr/p/Aes3Cj.

2: Body soft and yielding. Usual maximum length 40mm.

3: Voluminous tripinnate gills can contract but not retract into pocket; usually, opaque white along each side of midribs forms a star when gills expanded 4Ap flic.kr/p/NKYeKt .

4: Narrow oral veil extended laterally into broad, flat oral tentacles. Anterior of veil has two protrusions centrally. 12Ap flic.kr/p/Nrc6WE

5: Upper lamellated part of large rhinophores often bent backwards 7Ap flic.kr/p/NQxst9 .

Ecology

On mid- and lower-shore and sublittorally to about 170m. Adults occur in all months; commonest in spring when spawning at maximum. Spawn an undulating ribbon attached in a spiral of few turns.