Comprehensive DescriptionRead full entry
"Amauropsis powelli n.sp. (Figs 246, 268)
MATERIAL EXAMINED: Eltanin Stn 1535.
DISTRIBUTION: Known only from off South Georgia in 97-101 m.
DESCRIPTION: Shell large for genus in antarctic waters, solid, rather depressed, umbilicate. Height ranging from similar to diameter to rather less. Apical whorls worn in all specimens available, but apparently low. Whorls about 4 ½. Suture slightly impressed. Surface covered by a light brown epidermis, a darker olive brown in some specimens. Sculpture consisting of microscopic spiral striae. Whorls convex with a broad subsutural furrow, too indefinite to be more than a faint, broad concavity on the shoulder. Aperture ovate, outer lip slightly thickened, inner lip spread as a strong glaze over the parietal area. Columella thickened, white, curved to margin the narrow but definite umbilicus. Operculum horny and dark, paucispiral and substantial. Radula with a strongly tricuspid central tooth, lateral of the Amauropsis type, inner marginal bifid, outer marginal simple (Fig. 268).
MEASUREMENTS: height 22.7 mm, diameter 22.5 mm (holotype); paratypes, 18.8 x 19.6 mm, 17.8 x 18.2 mm, 16.6 x 17.6 mm.
HOLOTYPE: from Eltanin Stn 1535, in National Museum of Natural History (USNM 860103).
PARATYPES: from Eltanin Stn 1535 in National Museum of Natural History (USNM 860104) and in National Museum of New Zealand (two, MF.56600).
REMARKS: This new species is rather like a large A. anderssoni but retains a definite open umbilicus in the whole series available. It has a general ressemblance to Natica kerguelensis Thiele, 1925 (= psila Martens, 1903, non Watson, 1886) but has much less inflated whorls. The form of the radula places powelli in Amauropsis, but the open umbilicus separates it from all other members of the genus in this faunal area. Natica joubini Lamy, 1911 described from off the South Sandwich Islands is only a quarter the size, has only an umbilical chink and is more elongate. This species is named for Dr A.W.B. Powell, whose work on southern naticids has provided a basis for understanding the systematics of this group."
(Dell, 1990: 144)