Description: The body may be white or yellow and some rare individuals may have brown speckling on the mantle. The mantle bears flattened, stalked tubercles. The maximum body length is 14mm.

Habitat: This species feeds on a wide variety of encrusting bryozoans, but it is most often found on Membranipora membranacea on the lower shore or on Securiflustra securifrons in the sublittoral. The spawn consists of a ribbon, coiled several times.

Distribution: More common in the north of the British Isles than in the south. The species range extends into the Arctic circle. A few records exist for the French coast.

Similar Species: This species is most likely to be confused with Adalaria proxima, and often they occur together. O. muricata is generally smaller (up to 14mm), whilst A. proxima can reach 17mm in length and has tubercles with pointed tops. The radulae are so different that these species are placed in separate genera.

Key Identification Features:

• White or pale yellow animal with rounded tubercles.
• Tubercles with flattened tops.

Distribution Map from NBN: Onchidoris muricata at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Onchidoris muricata at iNaturalist World Species Observations database.

WoRMS: Onchidoris muricata at World Register of Marine Species. Accepted name: Onchidoris muricata (O. F. Müller, 1776). AphiaID: 140640.

Classification: Biota; Animalia; Mollusca; Gastropoda; Heterobranchia; Euthyneura; Ringipleura; Nudipleura; Nudibranchia; Doridina; Doridoidei; Onchidoridoidea; Onchidorididae; Onchidoris