Leptadrillia flavomaculata, Fallon, Phillip J., 2016

Fallon, Phillip J., 2016, Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species, Zootaxa 4090 (1), pp. 1-363 : 215-217

Leptadrillia flavomaculata , new species

( Plate 105 )

Type material. Holotype 11.2 x 3.5 mm (USNM 1199825); 3 paratypes, all from type locality: 10.6 x 3.5 mm (USNM 1199824); 12.3 x 3.4 & 11.8 x 3.7 mm (USNM 1199826). All types were recovered from in bottles, M. Harasewych! aboard submersible Curasub , 23 May 2012.

Type locality. Off Sea Aquarium, Bapor Kibra, Willemstad, Curaçao, Netherlands Antilles, 12°04.87'N, 68°53.75'W, in glass bottles collected at 130– 288 m.

Other material examined. An additional 13 specimens were examined: 11.2 x 3.5, 9.8 x 3.4, 12.1 x 3.8, 10.9 x 3.3, 11.6 x 3.4, 11.9 x 3.4, 10.1 x 3.3, 10.5 x 3.2, 10.1 x 3.1, 9.9 x 3.2, 9.7 x 3.1, 9.8 x 3.2, 7.9 x 2.6 & 6.3 x 2.5 mm, in old bottle at 244–274 m, off Sea Aquarium, Bapor Kibra, Willemstad, Curaçao, Netherlands Antilles, 12°04'59.51"N, 68°53'56.61"W, C. Baldwin! aboard submersible Curasub , 8 Feb 2013 (USNM 1231403).

Range and habitat. Netherlands Antilles (SE coast of Curaçao). Dead-collected from inside discarded beverage bottles at 130– 288 m. The 13 specimens appear to have been sequestered by an octopod. It is likely that the shells were first occupied by hermit crabs.

Description. Shell small (to 12.3 mm in total length), glossy, partially translucent, narrowly fusiform; whorls flat on shoulder and convex below, number up to about 10¼, the last approximately 54% of total length, with a narrow aperture only slightly wider than the anal sinus and anterior canal. Protoconch of 2 round glossy-smooth whorls. Axial sculpture of narrow, slightly opisthocline ribs that run from suture-to-suture on spire whorls, to anterior fasciole on last; ribs narrower than their interspaces, number 8–11 on penultimate, 6–10 on last whorl to varix. Varix rib-like in profile, about twice their height and width; straight, not opisthocline, positioned ⅓–½-turn from the edge of outer lip. Spiral sculpture absent on most of shell surface, limited to 6–7 low faint threads on anterior fasciole. Sulcus absent; ribs narrower on shoulder, flat in longitudinal profile, curved by slight hollow on trailing side of ribs formed by previous positions of the anal sinus. Outer lip thin, translucent, edge forming an arc from the anal sinus to anterior canal, strengthened by curved axial folds parallel to lip edge; edge bent upward at junction with anal sinus; curved outward along anterior canal. Anal sinus deep, apex round, sides straight, offset from shell axis by parietal callus on one side and outward curve of outer lip on the other, appearing spout-like. Inner lip narrow, margined, erect on anterior canal, formed into a parietal callus posteriorly; depositional layers visible on margin. Anterior canal long, open, only slightly narrower than aperture, turned right when viewed ventrally; end unnotched. Color light golden brown, anterior and first few whorls lighter; nucleus (tip of the protoconch) violet-colored; violet hue on some ribs, especially on post-varical axial folds; and yellow patch on leading side of varix and on anterior fasciole.

Remarks. Taxonomy. Leptadrillia flavomaculata has all of the distinguishing characteristics of Leptadrillia : a long, spindle-shaped shell with a narrow aperture and long anterior canal, ribs that extend from suture-to-suture without a sulcus, and no spiral sculpture except on the anterior fasciole. Variability. The 17 specimens have an average total length of 10.38 mm (6.3–12.3 mm), and W/ L ratio of 0.313. Identification. Leptadrillia flavomaculata is unique in possessing narrow, widely spaced ribs, and for its combination of colors. Its violet hue is reminiscent of L. violacea , new species but that species has wide ribs, wider than their interspaces. Leptadrillia flavomaculata differs from L. luciae , new species, with which it was found, in possessing narrower ribs and shell profile.

Etymology. The Yellow spot Leptadrillia . From the Latin adjectives flavus meaning yellow, combined with maculata, meaning spot. Named for the large yellow spot on the leading side of its varix and on the anterior fasciole of the freshest specimen.

Figures

PLATE 105. Leptadrillia flavomaculata, new species. Upper panel. Figs. 1 – 3: holotype, Curasub Sta. 4, off Sea Aquarium, Curaçao, Netherlands Antilles (USNM 1199825). Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged view of protoconch (not to scale); Fig. 3: apical view, V = varix, L = edge of outer lip. Lower Panel. Figs. 4 – 16: off Sea Aquarium, Curaçao, Netherlands Antilles. Fig. 4: Curasub Sta. 1 (USNM 1199824); Figs. 5 – 6: paratypes, Curasub Sta. 4 (USNM 199826); Figs. 7 – 16: Curasub Sta. 13 - 04 (USNM 1231403).