Leptadrillia incarnata, 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 : 220

Leptadrillia incarnata , new species

( Plate 108 )

Type material. Holotype 12.6 x 4.2 mm (USNM 900286); 6 paratypes: 1 spec., 11.7 x 3.9 mm, from the same lot as holotype (USNM 1291374); 2 spec., 13.8 x 4.5 & 11.6 x 3.7 mm, in 73 m, WSW of Egmont Key, Hillsborough Co., W Florida (EFG 14924); 2 spec., 10.4 x 3.8 & 13.7 x 4.7 mm, in 73 m, 153 km W of Egmont Key, Hillsborough Co., W Florida, J. Moore! aboard Cavalier, Aug 1968 (UF 470324); 1 spec., 12.6 x 4.4 mm, in 165 m, off Key West (USNM 411266).

Type locality. SW Gulf of Mexico in 73– 165 m.

Other material examined. An additional 11 specimens were examined: 3 spec., 10.2 x 3.5, 9.3 x 3.4 & 8.8 x 3.9 mm, in 88 m, offshore Louisiana, 28°4.57'N, 90°59.99'W, E García! aboard R/V Pelican, 4 July 2003 (EFG 24637); 1 spec., 10.8 x 3.7 mm, in 27–30 m, W of Anclote Keys, Pasco Co., W Florida, J. Moore! (ANSP 314399); 2 spec., in 73 m, 145 km WSW of Egmont Key, Hillsborough Co., W Florida, J. Moore! (ANSP 314390); 3 spec., 10.0 x 3.6, 10.6 x 3.9 & 11.9 x 4.1 mm, in 115 m, Eolis Sta. 43 off Key West, Florida Keys, J.B. Henderson Jr.!, 2 Jun 1911 (USNM 411269); 1 spec., 14.1 x 4.4 mm, in 55 m, S of Marquesas, Key West, Florida Keys (USNM 900287); 1 spec., 10.7 x 4.0 mm, in 91 m, off Pelican Shoals, Florida Keys (UF 362366).

Range and habitat. Louisiana; W Florida (off Pasco Co.; off Hillsborough Co.); Florida Keys (off lower Keys). Reported from 27– 168 m. One data label gives the substrate as “sand” (USNM 411269).

Description. Shell small (to 14.1 mm in total length), narrowly fusiform, glossy and translucent; whorls moderately convex with peripheries just below mid-whorl, up to 10¼ in number, last approximately 59% of total length; aperture narrow, anal sinus and anterior canal only slightly narrower; sculpture of axial ribs. Protoconch of approximately 2 smooth round whorls. Axial sculpture of strong, broad, bulging, slightly curved ribs that run suture-to-suture and to anterior fasciole on shell base, widest mid-whorl; lower, narrower, and slightly curved on shoulder; 7–8 on penultimate, 5 on body whorl to varix with intercostal space about as wide as ribs. Varix strong, larger and less oblique than preceding ribs; positioned about ¼- to ⅓-turn from the edge of the outer lip. Spiral sculpture absent except for threads on the anterior fasciole. Sulcus absent. Former positions of the anal sinus on the whorl shoulder indicated by narrower and recurved ribs with a slight hollow formed on the trailing side. Outer lip thin, with strengthening axial folds; lip edge flexed outward near the anal sinus; stromboid notch very shallow. Anal sinus deep, U-shaped, inner edge flared out; sinus offset laterally from the axis of the shell by the parietal lobe such that it appears spout-like. Inner lip recumbent, margined; thicker on the anterior portion of the columella, developed into a parietal lobe posteriorly. Anterior canal long, open, turned right when viewed ventrally, unnotched; fasciole not swollen, spiral threads present. Color of shell flesh with a yellow-brown band at suture between ribs, and along ventral side of varix, the latter broken by a white band near varix’s anterior end.

Remarks. Taxonomy. Leptadrillia incarnata has all of the distinguishing characteristics of the genus: a narrowly fusiform shell with a long anterior canal, ribs that extend from suture-to-suture, without a sulcus, and no spiral sculpture except for spiral threads near or on the anterior fasciole. Variability. The average total length of 18 specimens is 11.24 mm (8.8–14.1 mm); their average W/ L ratio is 0.355. Identification. Leptadrillia incarnata is easily recognized by its subsutural yellow-brown band and varix. It is most similar to L. luciae , new species from the southern Caribbean in that both possess yellow-brown subsutural bands; however, the latter species has a broader band and less convex whorls with whorl peripheries more anterior or closer to the suture. From L. splendida Bartsch, 1934 it differs in length (average total length 11.24 versus 9.85 mm) and in possessing fewer but broader, more bulging ribs (7–8 versus 9–11 on the penultimate whorl).

Etymology. The Flesh-colored Leptadrillia after the Latin adjective incarnatus (feminine incarnata ) meaning flesh-colored, named for the base color of the shell.

Figures

PLATE 108. Leptadrillia incarnata, new species. Upper panel. Figs. 1 – 3: Holotype, off W Florida, Gulf of Mexico (USNM 900286). Fig. 1: ventral, lateral and dorsal views; Fig. 2: enlarged view of protoconch (not to scale); and Fig. 3: apical view, V = varix, L = edge of outer lip. Lower panel, various localities in eastern Gulf of Mexico. Figs. 4 – 5: WSW of Egmont Key (ANSP 314390); Fig. 6: Pelican Shoals, Florida Keys (UF 362366); Fig. 7: off Key West, Florida Keys (USNM 411269); Fig. 8 – 9: off Louisiana (EFG 24637); Fig. 10: off Key West, Florida Keys (USNM 411269); Fig. 11: paratype, W of Egmont Key, Hillsborough Co. (UF 470324); Fig. 12: S of Marquesas Keys, Florida Keys (USNM 900287); Fig. 13: paratype, W of Egmont Key, Hillsborough Co. (UF 470324); Fig. 14 – 16: paratypes, off W Florida: Figs. 14, 16: EFG 14924; Fig. 15: USNM 1291374; and Figs. 17 – 18: off Key West, Florida Keys: Fig. 17: USNM 411269, Fig. 18: USNM 411266.