Tropidoturris vizcondei, Morassi, Mauro & Bonfitto, Antonio, 2013

Morassi, Mauro & Bonfitto, Antonio, 2013, Four new African turriform gastropods (Mollusca: Conoidea), Zootaxa 3710 (3), pp. 271-280 : 273

Tropidoturris vizcondei sp. nov.

Figures 1. A–H

Type material: Holotype (MNHN 26614). 4 Paratypes (2 from stn. CC 3175 (MNHN 26615); 1 from stn. CP 3143 (MNHN 26617); 1 from stn. CP 3133 (MNHN 26618); 1 (coated) from stn. CC 3175 (MZB 60071).

Type locality: Mozambique Channel (Maputo transect), 25° 34’S 34° 11’E, 155– 165 m.

Material examined: Mozambique Channel (Maputo transect): 25° 34’S 34° 11’E, 155– 165 m. [N/O “Vizconde de Eza” MAINBAZA, stn. CC 3175] (holotype and 3 paratypes); 25° 11’S 35° 10’E, 200– 201 m. [N/O “Vizconde de Eza” MAINBAZA, stn. CP 3133] (1 paratype); 23° 32’S 35° 46’E, 264– 277 m.[N/O “Vizconde de Eza” MAINBAZA, stn. CP 3143] (1 paratype).

Description: Shell (fig. A–C) fusiform-biconic (b/l 0.37–0.39; a/l 0.49–0.54), with a high spire; base tapering, shallowly excavated. Protoconch of 1 ½ strongly convex whorls (fig. F–G) with a series of weak axial growth ribs at termination; under SEM (fig. H) the protoconch surface is seen to be sculptured by microscopic rows of spiral threads more evident on terminal part. Protoconch diameter: 0.75–0.90 mm. Teleoconch of up to 5 whorls sharply shouldered at mid-whorl height, sutural ramp broad, shallowly concave. First teleoconch whorl with a prominent peripheral cord; in some specimens a second weaker cord just below the peripheral one. Two prominent spiral cords on second whorl, increasing to 3 on antepenultimate and penultimate whorls (in some specimens with a fourth narrow spiral cord at level of abapical suture) (fig. D). Last whorl with 3–5 spiral cords; 11–14 cords on base and rostrum. Axial sculpture of fine to relatively prominent growth lines. No axial ribs. Under SEM (fig. E) the surface of sutural ramp and the interspaces, between spiral cords, are seen to be covered by microscopic rows of slightly wavy spiral threads. Aperture narrowly lanceolate, tapering slightly towards base, truncated posteriorly at sinus. Columella and parietal region weakly convex, columellar callus thin. Siphonal canal short, shallowly notched. Outer lip thin. Anal sinus deep, relatively broad, occupying entire sutural ramp. Color uniform pale orange-yellow. Dimensions: Holotype: 11.1 x 4.3 mm, aperture height 6.0 mm; largest paratype (CP 3143): 13.2 x 5.1 mm, aperture height 7.2 mm; smallest paratype (CC 3175): 9.7 x 3.8 mm, aperture height 4.8 mm.

Etymology. Named after the research vessel “Vizconde de Eza” used in the dredging of the type material.

Remarks. Tropidoturris vizcondei sp. nov. is comparable only to Tropidoturris simplicicingula simplicicingula (Barnard, 1958) and T. planilirata Kilburn, 1986 in the complete lack of axial sculpture, but otherwise differs distinctly from both species mainly in its smaller dimensions (up to 13.2 mm versus 19.8 in T. simplicicingula simplicicingula and 16.8 mm in T. planilirata ), and in possessing fewer teleoconch whorls (up to 5 whorls versus 6 in T. simplicicingula simplicicingula and 5½ in T. planilirata ) sculptured by fewer spiral cords. In particular, Tropidoturris vizcondei sp. nov. has 3–4 and 3–5 spiral cords on penultimate and last whorl respectively while T. simplicicingula simplicicingula and T. planilirata have respectively 6–10 and 4–5 spiral cords (excluding peripheral cord) on abapical part of penultimate whorl. Furthermore, T. planilirata has 1–2 spiral cords on sutural ramp which are totally absent in T. vizcondei . The shell of T. vizcondei is uniform pale orange-yellow while that of both T. planilirata and T. simplicicingula simplicicingula is more vividly patterned with brown blotches. Finally, in Tropidoturris vizcondei the anal sinus seems broader than in any of its described congeners.

Figures

FIGURE 1. A – H. Tropidoturris vizcondei sp. nov. A – B. Holotype (MNHN 26614), 11.1 x 4.3 mm. C – H. Paratype (MZB 60071). C. Shell, scale bar 1 mm. D. Penultimate whorl, scale bar 500 µm. E. Surface microsculpture, scale bar 40 µm. F – G. Protoconch, scale bar 200 µm. H. Microsculpture of protoconch, scale bar 100 µm. I – K. Iredalea adenensis sp. nov. I – J. Holotype (MZB 60072), 17.2 x 7.7 mm. K. Penultimate whorl. L – P. Buchema shearmani sp. nov. L – M. Holotype (MZB 60073), 9.9 x 3.5 mm. O. Protoconch. P. Detail of penultimate whorl. Q – S. Crassispira somalica sp. nov. Q – R. Holotype (MZB 60076), 21 x 8.9 mm. S. Penultimate whorl.