Spongiobranchaea intermedia Pruvot-Fol, 1926
Overview
This is a large, naked pelagic snail, over 2 cm long, with a semi-transparent body. The body has chromatophores. There are two strong lateral arms, a median arm is absent. The arms each have 20 suckers. A posterior gill and a reduced lateral gill are present. The posterior footlobe is short, the wings and lateral footlobes are typical in size (Spongiobranchaea intermedia). It is a carnivorous species that lives in shallow and deeper waters in all oceans.
Taxonomic Description
The posterior gill is of the Spongiobranchaea australis type. The most posterior part of the body in the present species, however, is different as it is cylindrical, but this may be due to fixation. The lateral gill is reduced, absent in some specimens or only slightly developed. The wings are small, the median footlobe is short. The lateral lobes are rounded. A median foot tubercle could not be found. The dorsal gland patch is well developed. On each arm 18 to 20 large subequal suckers are found. Massy (1932) reported specimens with up to 80 suckers on each arm, but this may have been another species. Still the number of suckers is twice that found for S. australis. The head parts are relatively large. The Spongiobranchaea intermedia radula formula is 7-1-7, the median plate is quadri- or tricuspoid. The first lateral tooth structure provides a firm connection with the preceding and following laterals. Each first lateral tooth falls in a slit of the next one. The denticle, found in Spongiobranchaea australis, is strongly reduced or absent. At each side about 34 robust hooks are found. The strong and clearly bent hooks resemble those of Notobranchaea. The jaw is well developed, composed of numerous rows of spines, the basal spines are longer than those on top of the odontophore, which bears the jaw.
Body length up to 20 mm.
Juveniles
A special description is not available.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is carnivorous.
Distribution
It appears to be an eurythermic, cosmopolitan species, although at this moment it is only known from four localities; Panama, Dakar, and Argentine waters and Tasman Sea only, see the Spongiobranchaea intermedia map.
Types
Spongiobranchaea intermedia Pruvot-Fol, 1926: 7, pl. 1, figs. 10-13, pl. 2, figs. 66-67, pl. 3, figs. 68-69.
Holotype: MOM dissected (alcohol collection), u.s.
Type locality: 44°19'N 11°19'W. Coll.: CPAE, stat. 3003.