Benthofascis lozoueti Sysoev & Bouchet, 2001

Tucker, J. K., Tenorio, M. J. & Stahlschmidt, P., 2011, The genus Benthofascis (Gastropoda: Conoidea): A revision with descriptions of new species, Zootaxa 2796 (1), pp. 1-14 : 10-13

Benthofascis lozoueti Sysoev & Bouchet, 2001

Figures 3 , G–L; 4 , G

Type material. Holotype and 2 paratypes in MNHN, 1 paratype each in NMNZ, AMS, NMSA.

Type locality. 530 m, Norfolk Ridge , 22º58'S, 167º20'E

Range. Known only from the type locality.

Description. Shell biconic, rather thick, with moderately high spire, comprising 30% of shell height. Protoconch very large, diameter ca. 2500 µm, dome-shaped, consisting of about 2 rapidly expanding whorls, transition to teleoconch indistinct; initial whorl strongly flattened; sculpture of very fine spiral and axial lines. Teleoconch whorls 4, weakly convex, subsutural ramp unclearly defined, especially on early whorls. Suture weakly channeled. No axial sculpture. Spiral cords weak, low, with wide interspaces, much stronger on subsutural ramp and canal, very weak on whorl periphery. Base almost flat. Canal short, broad, strongly turned abaxially, slightly notched. Aperture rather narrow, pyriform. Inner lip evenly curved, with concave columellar part, covered by narrow but thick callus. Anal sinus is broad and shallow, occupying entire subsutural ramp, outer lip greatly projecting below sinus, most strongly projecting below its middle. Color white, periostracum very thin, yellowish. Dimensions: shell length 21.5 mm, last whorl height 15.0 mm, aperture length 11.5 mm, shell width 9.1 mm. The radular tooth is relatively large with a long, narrow, straight blade and a small rounded basal part ( Fig. 4G ). The operculum is narrow with a large terminal nucleus. (description is adapted from Sysoev & Bouchet 2001, p. 292).

Discussion. This species differs from all other Benthofascis in having the sculpture of the protoconch reduced to numerous exceedingly thin and minute spirals and by not having the inner shell walls greatly resorbed ( Fig. 3H ). Axials are also minute. The appearance is that of a smooth protoconch. Other Benthofascis species have much better developed spirals on the protoconch. The species is only provisionally considered a Benthofascis in light of the above differences.

Small specimens of Benthofascis lozoueti resemble the holotype of B. sarcinula in shell shape. Both have the whorls rounded and convex. However, the spirals and axials of the protoconch of B. sarcinula are more obvious than those of B. lozoueti . Larger specimens of B. lozoueti tend to be more angular and have an obvious shoulder. In this respect they resemble B. angularis . However, the latter species has a distinctly ornamented protoconch.

Figures

FIGURE 3. A–C. Holotype of Benthofascis conorbioides new species (MNHN 23068, trawled 80–120 m, off Mooloolaba, S. Queensland, Australia), height 38.7 mm, width 15.4 mm, ventral view (A), with an enlargement of the spire (B) and an x-ray (C). D. Paratype of Benthofascis conorbioides new species (SBMNH 424097, trawled on sand and rubble, 80–120 m, off Mooloolaba, S. Queensland, Australia) height 41.8 mm, width 17.0 mm, ventral view. E. Holotype of Benthofascis atractoides (SAMA T750A, Kent Town Bore, Clayey greensands, Janjukian?, L. Miocene), height 16.5 mm, width 6.5 mm (reproduced from Long, 1981, Pl. 6, Fig. 14, with permission), ventral view. F. Holotype of Benthofascis otwayensis (NMVM P42959, Point Flinders, Cape Otway, Victoria, Australia. Glen Aire Clay, U. Aldingan, L. Oligocene), height 19.75 mm, width 8.75 mm (reproduced from Long, 1981, Pl. 6, Fig. 15, with permission), ventral view. G. Paratype of Benthofascis lozoueti (NMSA L5679/T1867), South New Caledonia, N/O "Alis" campaign, Stn. DW 721, 22º54'S, 167º17'E, height 16.5 mm, width 7.2 mm, ventral view. H. Benthofascis lozoueti (MNHN IM200742331, 496 m deep, Norfolk Ridge, 22º50'S, 167º16'E), length 16.4 mm, width 7.0 mm, x-ray. I–K. Holotype of Benthofascis lozoueti (MNHN 3053, 530 m deep, Norfolk Ridge, 22º58'S, 167º20'E), height 21.5 mm, width 15 mm, ventral (I) and lateral (J) views with an enlargement of the spire (K). L. Paratype of Benthofascis lozoueti (AMS C.415308), 525–574 m deep, New Caledonia, 22º54'S, 167º17'E, height 17.5 mm, width 8.0 mm, ventral view. Scale bars represent 1 mm.

FIGURE 4. A, B. Radular teeth extracted from Benthofascis biconica (AMS C.468232, shell length of 15.5 mm), photomicrograph (A) and drawing (B) showing internal structures. C, D. Radular teeth extracted from Benthofascis biconica (AMS C.468234, shell length of 15.2 mm), photomicrograph (C) and drawing (D) showing internal structures. E, F. Radular teeth extracted from Benthofascis pseudobiconica (AMS C.373099, shell length of 17.3 mm), photomicrograph (E) and drawing (F) showing internal structures. Scale bar represents 0.1 mm for A–F. G. G. Electron micrographic study of the radular tooth of Benthofascis lozoueti Sysoev & Bouchet, 2001, (MNHN IM200742331, 496 m deep, Norfolk Ridge, 22º50'S, 167º16'E, height 16.4 mm, width 7.0 mm, teeth from the same specimen shown in Fig. 3H). Scale bar dimensions are explained in the figure.