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Rim-backed Nudibranch

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Mollusc

Rim-backed Nudibranch

Palio dubia (M. Sars, 1829)

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WoRMS AphialID

182807

Barcode BIN

BOLD:AAX1867

Sample IDs

HMSC174-00225|https://bench.boldsystems.org/index.php/MAS_DataRetrieval_OpenSpecimen?selectedrecordid=ATCMO018-23; HMSC174_01053|https://bench.boldsystems.org/index.php/MAS_DataRetrieval_OpenSpecimen?selectedrecordid=ATCMO120-24; HMSC174-03414|https://bench.boldsystems.org/index.php/MAS_DataRetrieval_OpenSpecimen?selectedrecordid=ATCMO241-24

Collected

Mouton Island, NS; Les Escoumins, QC; and New River Beach, NB; from rocky intertidal hand collection and SCUBA collection of bryozoans, 0-19 m depth.

Distinguishing Features

• Head: anterior margin is curved, with a notched hood, and yellow marginal papillae. The rhinophores are short, translucent brown, with 8 oblique laminae.
• Body: pale to dark yellowish green with yellow-tipped tubercles, rhinophores, and branchial plume. The tubercles are scattered all over and occur in a row along the dorsolateral ridges. Characteristically, there are whitish compound papillae on either side of the mid-dorsal gills.
• Gills: 3-5 translucent brown, tripinnate gills occur mid-dorsally on the body.
• Size: to 29 mm.

Habitat

Shallow subtidal to 100 m, on bryozoans.

Geographic Range

Widespread across cold-temperate waters of the Northern Hemisphere from the North Pacific to the North Atlantic and extending into the Arctic. In the Northwest Atlantic, occurs from the Gulf of St. Lawrence south to Massachusetts.

Fun Fact

This slow-moving, striking nudibranch can be found preferentially feeding on bryozoan colonies of Eucratea loricata. The yellow-tipped tubercles and broadly round, bumpy frontal margin of the mantle make it distinct from other common nudibranchs in the area. Mating typically peaks around the full moon in late spring, when they gather in clusters, and undergo a courtship ritual. Two to three days after mating, they lay pale pink egg strings on bryozoans which hatch around the new moon. Free-swimming larvae develop, reaching full-size in about 3 months.

Barcode Distribution

Amphi-Atlantic BIN matching specimens from Norway

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