Amphorina pallida (Alder & Hancock, 1842)

See Korshunova et al 2020.

Synonyms: Eolis pallida Alder & Hancock, 1842; Eolis picta Alder & Hancock, 1847;

Body (excluding appendages)
Length up to 23mm. Translucent white with rich mahogany pigment flecks that usually coalesce on dorsum [image 1]. Sometimes, also white and gold flecks, but no greenish ones.
Cerata
 Arranged in up to ten groups along each side. Up to seven inflated cerata in each group, the dorsal ones larger than the peripheral. Translucent white revealing brown or pale-brown internal digestive gland. Flecks of mahogany and white surface pigment. Distally white with sub-apical gold ring.
Rhinophores
Twice as long as oral tentacles. Smooth, translucent white with mahogany flecks basally and mahogany band two-thirds of way up. Also white pigment freckles.
Head
Dorsally, white, with mahogany flecks and some white flecks spreading onto it from oral tentacles. Small black eyes set back from rhinophores [1]. Oral tentacles translucent white with mahogany flecks and band half way up, also freckles of white pigment. Ventrally, large cylindrical mouth, slit ventrally [2].
Foot
Widest at anterior [2], but no propodial extension or tentacles. Tapers gradually to posterior.Sole translucent white.

Key identification features

• Inflated smooth cerata distally white with sub-apical gold ring.

• Mahogany and white pigment marks on body, never greenish. 

• Basal mahogany mottling on white translucent rhinophores and oral tentacles [1].

• Band of mahogany two-thirds way up rhinophores and half way up oral tentacles.

Similar species

Eubranchus farrani

• Cerata smooth, changeable, but always at least moderately inflated.

• Usually orange pigment blotches on body.

• Usually orange subterminal band on cerata.

• Rhinophores and oral tentacles, part or completely orange.

Eubranchus tricolor

• Cerata smooth, like flattened rugby balls.

• Dorsum concealed by crowded cerata (up to 150).

• Body pale yellow or greyish white.

• Subterminal golden-yellow and white bands on cerata.

• Inside cerata; indistinct red-brown digestive gland often tinged violet distally.

• Rhinophores and oral tentacles; pale yellow-brown with paler tips.

  Ecology and behaviour

Low water spring tides and sublittorally to 60m. Eats a range of hydroids, including Obelia geniculata (EML)  Simultaneous hermaphrodite. Spawn [3] a spiral ribbon attached by its edge to substrate, recorded in May and July. Several generations p.a.

Distribution and status

Norway to Mediterranean and New England(USA). (GBIF map) Widespread in Britain and Ireland (interactive UK distribution map. NBN)

References and links

Alder, J. & Hancock, A. 1845-1855. A monograph of the British nudibranchiate mollusca. London, Ray Society.
Thompson, T.E. & Brown, G.H. 1984. Biology of opisthobranch molluscs 2. London, Ray Society.
Current taxonomy; World Register of Marine Species (WoRMS)