Planaria dorsalis Abildgaard, 1806, Denmark.
OTHER COMMON NAMES None known.
Small, rather stout, up to 1.2 in (30 mm); most specimens 0.4-0.6 in (10-15 mm) long and 0.04-0.07 in (1-2 mm) wide. Head bluntly rounded, not demarcated from body, with four eyes. Extremely variable in color; more or less uniform brown to reddish brown with mid-dorsal white stripe, or with irregular light or dark
brown speckles varying in size and shape between specimens. Some specimens have yellowish dots, some specimens are cream without pigmentation, others with regular dark bands on light background. Ventral surface usually paler than dorsal.
Widely distributed in the northern hemisphere; found in the Baltic Sea, the North Sea, the Mediterranean, on eastern Atlantic coasts from northern Europe to Madeira, and both Atlantic and Pacific coasts of North America down to Mexico.
Marine, littoral and sublittorally, down to 260 ft (80 m). Generally associated with small algae, especially species of Ce-ramium and Corallina.
Lives among algae. No other details known. FEEDING ECOLOGY AND DIET
Not known in detail, but probably small crustaceans and other worms.
Dioecious, external fertilization.
Not listed by the IUCN. Common.
SIGNIFICANCE TO HUMANS None. ♦
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