(M. Sars, 1829)
Flabellina verrucosa, common name red-finger aeolis, is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Flabellinidae. It is found on either side of the northern part of the Atlantic Ocean.
Flabellina verrucosa is a translucent pale colour covered with warty projections ("verrucose") and grows to a length of about 25 mm (1.0 in). The tentacles that surround the mouth and the central part of dorsal surface of the body are solid white. Some individuals have a scanty covering of clumps of large cerata (elongated outgrowths from the skin) whereas other specimens have a more profuse covering of smaller cerata. This nudibranch is similar in appearance to Flabellina gracilis but in that species, the cerata are arranged in more distinct rows. The tail is elongated and pointed and has round translucent spots. In different parts of its range this species has differently coloured forms, in some places having red cerata with solid white tips while in other locations, brown cerata predominate. The colouring may also depend on what the animal has been feeding on recently.
Distribution and habitat
This species is widespread in the North Atlantic Ocean and has also been found in the North Pacific Ocean. In the British Isles it is restricted to northern England and Scotland. It also occurs in Norway. In North America, its range includes the Gulf of St Lawrence and the Gulf of Maine. Flabellina verrucosa lives at depths down to about 300 metres (980 ft) and seems to inhabit both sandy and rocky habitats.
Flabellina verrucosa grazes on sessile invertebrates on the sea bed. It also feeds on detritus and plankton. In the United Kingdom, it lives almost exclusively on the oaten pipes hydroid (Tubularia indivisa). The juveniles have a wider diet range.
Flabellina verrucosa has the ability to incorporate nematocysts from its prey into the tissue of its cerata as a defence. It was found experimentally that when the nudibranch was kept in the vicinity of certain predators such as the common sunstar (Crossaster papposus), the bergall (Tautogolabrus adspersus) (a fish) and the shore crab Carcinus maenas, it incorporated more nematocysts than it did in a predator-free environment.
Flabellina verrucosa is a hermaphrodite but self-fertilisation does not occur. Two adults engage in an elaborate touching ritual that was at first thought to be agonistic behaviour. The tentacles touch each other and are then withdrawn repeatedly and there is biting, lunging and sidling. The actual act of copulation is very quick. The eggs are laid in a gelatinous string neatly coiled in a spiral on the seabed. After hatching, the veliger larvae drift as part of the plankton, eventually settling on the seabed.
- Sars M. (1829). Bidrag til soedyrene naturhistorie, Pt. 1: pp. 1-59, pls. 1-6. Bergen.
- World Register of Marine Species Retrieved July 04, 2012
- Bill Rudman. "Flabellina verrucosa (M. Sars, 1829)". The Sea Slug Forum. Retrieved 2012-12-24.
- Picton, B. E.; Morrow, C. C. (2010). "Coryphella verrucosa (M Sars, 1829)". Encyclopedia of Marine Life of Britain and Ireland. National Museum of Northern Ireland. Retrieved 2012-12-24.
- Seawater Norway Retrieved July 04, 2012
- Frick, K. (2003). "Response in nematocyst uptake by the nudibranch Flabellina verrucosa to the presence of various predators in the Southern Gulf of Maine". Biological Bulletin 205 (3): 367–376. doi:10.2307/1543299. PMID 14672990.
- Carefoot, Tom. "Reproduction: Mate selection and copulation". A snail's odyssey: Nudibranchs and relatives. Retrieved 2012-12-24.
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