Buchema shearmani, Morassi, Mauro & Bonfitto, Antonio, 2013

Morassi, Mauro & Bonfitto, Antonio, 2013, Four new African turriform gastropods (Mollusca: Conoidea), Zootaxa 3710 (3), pp. 271-280 : 276-277

Buchema shearmani sp. nov.

Figures 1 . L–P

Type material. Holotype (MZB 60074) and 2 paratypes (MZB 60075); 1 paratype (MNHN-IM- 2012-2533)

Type locality. Offshore Mogadishu ( Somalia), trawled by local fishermen at unknown depth in 1989–1990.

Material examined. The type material.

Description. Shell (fig. L–M) claviform (b/l 0.34–0.35; a/l 0.33–0.35), with a high, slightly inflated spire, blunt apex and subcylindrical last whorl. Protoconch (fig. O) bluntly conical of 1¾–2 whorls; first 1½ sculptured by stout axial ribs; last portion with thinner, closely spaced ribs crossed by spiral threads. Protoconch diameter: 0.74–0.86 mm. Teleoconch of 5½–5 ¾ convex whorls, with periphery at ⅔–¾ of whorl height; subsutural margin forming a weak cord. Sculpture of prominent, opisthocline axial ribs crossed by low, flat-topped spiral cords becoming swollen over axial ribs. Axial ribs straight, but slightly arcuate over sutural ramp where they are weaker, narrower than their intervals, projecting most at periphery, fading across base at level of parietal region. Eight to 9 axial ribs on penultimate whorl, 9–10 on last whorl. Spiral sculpture of three main spiral cords, the upper one rather more slender than the others. Additional 1–2 cords, weaker than others, develop on later two teleoconch whorls. Interspaces between spiral cords sculptured by low spiral threads which decussate dense, fine axial lines (fig. P). On later two teleoconch whorls about 3–7 spiral threads, varying in strength, in each interval between spiral cords. Sutural ramp with a low, feeble to nearly obsolete spiral lira preceded by 2–5 threads and followed by others 6–7.

Aperture narrow, quadrangular. Columella straight, with relatively thick callus, its outer edge not raised; parietal pad forming a prominent nodule, which greatly restricts entrance of anal sinus. Outer lip with a slight stromboid notch in the abapical part, almost straight in lateral view, with a cutting edge, preceded by a varicoid rib. Anal sinus moderately deep, C-shaped. Color: a) brownish orange with ivory white spiral cords where they cross the axials. Interior of the aperture orange-yellow; b) uniform dark brown. Dimensions: Holotype 9.9 x 3.5 mm; aperture 3.5 mm; largest paratype (MZB): 10.6 x 3.6 mm, aperture 3.5 mm.

Etymology. Named after professor John K. G. Shearman (1931–2003) well known art historian.

Remarks. The new species differs distinctly from all its described congeners. Of the five Buchema species from Puerto Rico proposed by Corea (1934), Buchema shearmani sp. nov. superficially resembles in general features the type species Carinodrillia (Buchema) tainoa Corea, 1934 but the latter is larger (14.2 mm versus up to 10.6 mm in length), with a much broader and stronger shoulder. Furthermore, shell colour of B. shearmani varies from brownish orange with ivory white spiral cords to uniform dark brown while B. tainoa has a brown shell with interspaces darker than the axial ribs and “summit of the whorls marked by brown spots separated by lightercolored intervals” ( Corea, 1934). Buchema shearmani differs from the southern Africa Buchema dichroma Kilburn, 1988 in its much narrower shell (b/l 0.34–0.35 versus 0.43–0.47), sculptured by much fewer and weaker spiral cords and very different colour pattern (brownish orange with ivory white spiral cords or uniform dark brown versus bicolored yellow and violet) (Kilburn, 1988: 244, figs. 188–189). Buchema dichroma further differs from both Buchema shearmani and other Buchema species described by Corea (1934) in details of the protoconch which consists of smooth whorls except for few weak axial riblets crossed by feeble spiral striae near termination (Kilburn, 1988: 246). Actually the morphologically closest species is probably Crassispira soamanitraensis Bozzetti, 2008 , from Madagascar, which is comparable in dimensions and color and may prove referable to the genus Buchema . However, Crassispira soamanitraensis differs from the new species in having stronger, more closely spaced spiral cords.

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.