(Montagu, 1804)
Description:
This is one of the largest species of Doto , reaching 29 mm in length, with a pale fawn body, with dark brown or black mottling above, darkest anteriorly. (The coloration of the body darkens with age.) There are conspicuous dark brown spots around the flared rim of each rhinophore sheath and on the tips of small tubercles down each side of the body. The cerata (up to 10 pairs) bear about 6 concentric circlets of elongated tubercles, each containing a small but conspicuous dark brown or black spot.
A conspicuous recognition feature is the presence of a number (2-9) of simple, black-tipped tubercles along each flank (D. pinnatifida-drawing). One or two similar tubercles may occur also on the dorsum.
Habitat:
D. pinnatifida feeds exclusively on the hydroid Nemertesia antennina in quiet, shallow sublittoral localities.
Distribution:
It is common on the west coasts of the British Isles. On the North Sea coast it is known from the Moray Firth (Distr. D. pinnatifida). There are rare reports from southern Norway and from northern Spain.