"Lophiotoma pseudoannulata n.sp. (Figs 392, 432)
MATERIAL EXAMINED: NZOI Stns A464, A529; Eltanin Stns 2081, 2121.
DISTRIBUTION: Known only from the Ross Sea in 205-1890 m.
DESCRIPTION: Shell of medium size, white, biconic. Spire relatively squat, a little less than one third the height of the aperture plus canal. Whorls five, including a protoconch of two smooth, bulbous whorls with a few brephic axial riblets towards the close of the last whorl. Spire whorls with a strong, bluntly rounded median peripheral carinae with a second closely spaced subsidiary carina above. On the penultimate whorl these two carinae have become subequal, the space between sculptured by 1-2 minor spiral cords. On the last whorl a second set of double carinae is developed at the level of the adapical margin of the aperture, with a single prominent spiral cord below. The ramp on the penultimate whorl bears 2-4 minor spiral threads and 2-4 below the lower double carina. Last whorl with 3-5 spiral threads on the sutural ramp and 3-5 between the two major double carinae. Numerous strong spiral cords run over the rest of the last whorl, base and canal, 20-22 in adults (16 on the smallest paratype).
Axial sculpture relatively minor, little more than accentuated growth lines in the interstices, rendering the minor spirals slightly nodulous but not crossing the major carinae. Suture slightly impressed. Aperture narrowly ovate, drawn out anteriorly to form a long, straight, open canal. Outer lip thin, angled by the major spiral sculpture. Outline of outer lip sloping steeply back from the ,suture across the ramp to form a relatively deep, rounded sinus, occupying the full extent of the primary double carina, then sweeping forward in a broad curve which contracts gradually and evenly on to the neck of the canal.
Operculum brown, oval, with a flattened base, and a latero-terminal nucleus. Radula (Fig. 432) with a pair of rather short, stout marginals of modified wish-bone type, and a narrow, broad based, delicate central tooth bearing a relatively small median cusp.
MEASUREMENTS: height 19.0 mm, diameter 8.4 mm (holotype), height 15. 1, diameter 7.3 mm (paratype), height 9.5 mm, diameter 4.9 mm (paratype).
HOLOTYPE: from Eltanin Stn 2121 in National Museum of Natural History (USNM 860146).
PARATYPES: from NZOI Stns A464 (one, P.754) in NZ Oceanographic Institute, and from NZOI Stn A529 (one, MF.56620) in National Museum of New Zealand.
REMARKS: This new species bears a surprising superficial resemblance to Pleurotomella (Anomalotomella) annulata Thiele, 1912. The sinus is, however, situated on the peripheral carina and not on the ramp. Thiele's figure of annulata shows a sinus typical of Pleurotomella and a specimen close to annulata from the Ross Sea confirms this character.
The generic placing of pseudoannulata in Lophiotoma can only be provisional. The position of the sinus on the peripheral carina and the form of the radula indicate a position in the subfamily Turrinae. The only genus in the subfamily which could accommodate pseudoannulata would seem to be Lophiotoma. However, the relatively short spire and the presence of a central tooth in the radula appear to be discordant features, and the known range of species of Lophiotoma appears to be the tropical Indo-Pacific. Until more is known of the antarctic turrids it seems premature to erect a new genus for this species alone."
(Dell, 1990: 235-236)
Lophiotoma pseudoannulata is a species of sea snail, a marine gastropod mollusk in the family Turridae, the turrids.[1]
The length of the shell attains 20 mm.
This species occurs in the Ross Sea, Antarctica at a depth of 1890 m.
Lophiotoma pseudoannulata is a species of sea snail, a marine gastropod mollusk in the family Turridae, the turrids.
