Limapontia capitata (O F Müller, 1774)

Author & date of last revision: Ian Smith on 4 April 2013

Synonyms:Limapontia nigra Johnston, 1836;

Description

Body

Usually up to 4mm long, occasionally 8mm. Smooth body with no tubercles or appendages, apart from curved rhinophoral crest [image1] above and in front of each eye. Crests absent on juveniles, and may be weakly [4] or well [5] developed on adults. Body black [1] or dark brown [4] apart from translucent white, spotted with white pigment, on dorsal rim of foot, dorsal surface of metapodium (tail), eye areas and rhinophoral crests [1], and, often, the central area of the back [3]. Usually, light spots on dark areas, and sometimes small greenish patches with a few reflective flecks of green. Anus a short distance behind mid point of body, set to right of dorsum. (Often difficult to see, except when defecating.)
Head
Anterior edge truncated, extends beyond foot [2]. No digitiform rhinophores or oral tentacles.
Foot
Sole translucent white spotted with white pigment [2]. Reveals viscera, often two shades of green. No propodial tentacles or extensions, but anterior of foot slightly swollen.

Key identification features

Curved rhinophoral crest above and in front of each eye [1], no ridge below eye, and no digitiform rhinophores. At some angles of view, crests can be mistaken for digitiform rhinophores [6].
Dorsal surface of metapodium (tail) [3], eye areas and rhinophoral crests all whitish [1].
Anus a short distance behind mid point of body.
Not in brackish water. (But may be swept into salting pools in full salinity sites.)

Similar species

Limapontia depressa

No tentacles or rhinophoral crests but some have ribs/sharp edges to recessed eye-area, above, in front of and below eye) [1Ld] .
Pale metapodium (tail) absent or negligible.
Dorsal anus close to posterior.
In brackish or fully marine salinity (though slow to adapt to change in salinity).

Limapontia senestra

Pair of tentacles on head when 2mm long or larger, with or without anterior crest.
Pale metapodium.
Anus a short distance behind mid point of body.
Full salinity, also brackish Fleet lagoon, Dorset and variable salinity pools at MHWS on exposed coasts.

Ecology and behaviour

Mid and lower shore where fully marine salinity, usually in pools on its foodplants; Cladophora [3Ls], Bryopsis [9Ev] and Enteromorpha. Spawn, June - November. Veliger larvae in plankton for about a week before metamorphosis.

Distribution and status

Arctic to Mediterranean ( GBIF map). Common and widespread around Britain and Ireland. ( UK interactive distribution map, N.B.N.)

References and links

Eliot, C.N.E. 1910. A monograph of the British nudibranchiate mollusca. London, Ray Society. Supplementary Volume.
Thompson, T.E. 1976. Biology of opisthobranch molluscs 1. London, Ray Society.
Current taxonomy; World Register of Marine Species (WoRMS)

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Photo:

Limapontia capitata. Length 3mm. Metapodium (tail), eye areas, rhinophoral crests and central area of back, all white. Small greenish patches with a few reflective flecks of green. Menai Strait, Wales. April 2011.

Photo:

Limapontia capitata. Length 3mm. Large distinct white metapodium (tail). Most of head and central dorsum pale. Menai Strait, Wales. April 2011.

Additional images

GALLERY of larger images of this species.
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Recorded UK distribution

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