Onchidoris oblonga (Alder & Hancock, 1845)

Onchidoris oblonga

Description: The body of this nudibranch is narrow in comparison with other onchidorids. The mantle bears small rounded tubercles and is grey in colour with a few darker blotches on the back. It may grow to up to 8mm in length but most individuals are approximately 5mm long.

Habitat: This species is well camouflaged on its prey, Cellaria fistulosa, an erect, sublittoral bryozoan. The spawn consists of a rounded mass of eggs looking like a swelling on the branch of the Cellaria.

Distribution: Onchidoris oblonga is found at scattered localities on the southern and western coasts of the British Isles but is rarely recorded. Recent records include Lundy, Plymouth, the Irish Sea and the west coast of Scotland.

Key Identification Features:

Distribution Map: NBN map : National Biodiversity Network mapping facility, data for UK.

WoRMS: Species record : World Register of Marine Species.

iNaturalist: Species account : iNaturalist World Species Observations database

 Picton, B.E. & Morrow, C.C. (2016). Onchidoris oblonga (Alder & Hancock, 1845). [In] Encyclopedia of Marine Life of Britain and Ireland. Accessed on 2024-07-13

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