Leptadrillia lizae, 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 : 222-223

Leptadrillia lizae , new species

( Plate 109 )

Type material. Holotype 8.9 x 3.2 mm, E. García! aboard R/V Pelican, 10 Jun 2005 (UF 470325); 3 paratypes: 8.1 x 2.9, 8.6 x 2.9 & 7.3 x 2.8 mm, in 63–65 m, from the type locality, E. García! aboard R/V Pelican, 10 Jun 2005 (P. Stahlschmidt coll.).

Type locality. Off Triángulos Reefs, outer Campeche Bank, ca 205 km W of Yucatan State, Mexico (20°51.49' N, 92°21.44' W), in 63–65 m on mud.

Other material examined. An additional specimen believed to be this species was examined: 9.3 x 2.9 mm, in 457 m, W of Tampa Bay, Hillsborough Co., W Florida (ANSP 465632).

Range and habitat. Mexico (off Triángulos Reefs, Campeche Bank). Reported at 63–65 m, on mud, for specimens from the type locality, and at 457 m for a specimen from W of Tampa Bay.

Description. Shell very small (to 9.3 mm in total length), fusiform, translucent, glossy-smooth, with up to 9¼ smooth convex whorls with impressed sutures, the last approximately 56% of the total length; sculpture of axial ribs; aperture narrowly oval, only slightly wider at its widest than anterior canal. Protoconch of 2 smooth whorls, the first partially immersed in the second. Axial sculpture of narrow ribs that run from suture-to-suture, are slightly opisthocline, 12 are on penultimate, 8–11 on last whorl to the varix where they end at the anterior fasciole. Ribs somewhat wider than intercostal space. First 4 teleoconch whorls rib profiles angular, appearing nodulose on first 2, becoming less angular anteriorly; their peripheries just below mid-whorl. Rib crests round. Growth striae microscopic, oblique to ribs, recurved in sulcal area. Varix large, about twice the width of preceding ribs, straight, not opisthocline, not curved in the sulcal area; positioned ⅓-turn from edge of outer lip. Spiral sculpture absent except for distinct threads on shell base and anterior fasciole, most of which are on the fasciole. Sulcus absent; the only trace of the anal sinus is slightly recurved ribs and growth striae on whorl shoulders. Outer lip thin, with 2 strengthening axial folds; edge of lip forms a low arc from anal sinus to beginning of anterior canal; stromboid notch broad and shallow. Anal sinus is a deep U-shaped notch near the suture, sides not constricted by parietal callus, inner edge weakly flared at its apex. Inner lip thin, emarginated, thickest on anterior canal; thinnest on parietal wall, and formed into a weak callus posteriorly over roof of aperture. Anterior canal moderately long, open, unnotched. Anterior fasciole not swollen; with spiral threads. Color translucent white; first protoconch whorl with a violet tint.

Remarks. Taxonomy. Leptadrillia lizae displays all the characteristics of Leptadrillia : a slender shell with a long anterior canal, ribs extending from suture-to-suture with only a slight change in the sulcal region, and spiral sculpture absent except near and on the anterior fasciole. The anterior canal is somewhat shorter than most of its congeners. Variability. The average total length of five specimens is 8.44 mm (7.3–9.3 mm) and their average W/ L ratio is 0.346. Identification. Leptadrillia lizae is most similar to L. splendida Bartsch, 1934 , L. histriata , new species, and L. loria Bartsch, 1934 , two of which also occur in the Gulf of Mexico. From L. splendida it differs in possessing less angular and more evenly rounded whorls, straighter and more numerous ribs (12 versus 10 on penultimate whorl of L. splendida ), and a somewhat shorter anterior canal. The ribs of L. splendida are more arcuate and whorl peripheries are below mid-whorl. From L. loria it differs in being larger (8.44 mm versus 6.8 mm in total length), and in possessing a more evenly rounded and more convex whorls. Whorl peripheries are also below mid-whorl in L. loria , as in L. splendida . From L. histriata it differs in having more convex whorls and usually fewer ribs (12 versus 11–15 on the penultimate whorl).

Etymology. Liz’s Leptadrillia . Named after my daughter, Elizabeth A. Fallon.

Figures

PLATE 109. Leptadrillia lizae, new species. Figs. 1 – 3: holotype, off Triángulos Reefs, Campeche Bank, Yucatan State, Mexico (UF 470325). Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged view of the protoconch (not to scale); Fig. 3: apical view, V = varix, L = edge of outer lip. Fig. 4: specimen possibly this species, from W of Tampa Bay, Hillsborough Co., W Florida (ANSP 337390); Figs. 5 – 7: paratypes from type locality (P. Stahlschmidt coll.).