Cnemidocarpa verrucosa Lesson 1830

Cnemidocarpa verrucosa (Lesson, 1830)

Fig 9

References and synonymy: Cnemidorcarpa verrucosa Lesson (1830a) p. 151; (Kott 1969) p. 106; Monniot & Monniot (1983) p 68; Monniot et al. (2011) p. 34.

Localities: 7S

Individuals are big (reaching 15 cm in height), cylindrical, posteriorly fixed and with anterior siphons. The colour is yellowish and the tunic is relatively thin but consistent, with plenty of tubercles and warts that give the species its name. The mantle has circular and longitudinal muscular bands. The siphons are featureless but for a thin reddish rim. Internally there are>30 simple oral tentacles, the aperture of the neural gland is “U” shaped with both horns rolled inwards. The dorsal lamina is smooth and simple, and there are four branchial folds with 1–3 longitudinal vessels between folds (none between the dorsal-most fold and the dorsal lamina) and 9–12 on the folds. The wide spacing between longitudinal vessels between folds results in large numbers of stigmata (up to 50 or more) in a given branchial mesh.

The digestive system comprises a voluminous stomach and an intestine describing a closed primary loop and a marked secondary loop ending in a scalloped anus. There are big endocarps near the digestive and between the gonads at both sides. There are two big, elongated gonads at each side, with a terminal female opening surmounted by a small male papilla.

Remarks. This species is very abundant in Antarctic zones and, in the subantarctic area, it is known from the Magellanic region, South Georgia, and Kerguelen Islands (Monniot & Monniot 1983, Tatián & Lagger 2010).