Lissodrillia levis, 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 : 246-247

Lissodrillia levis , new species

( Plate 125 )

Lissodrillia simpsoni auct. non (Dall, 1887): is a misidentification by Lee (2009: 124, species 599). The illustrated specimen (species 599) is a paratype (Pl. 125, Fig. 6).

Type material. Holotype 6.7 x 2.5 mm, ex batfish, scallop boats! H.G. Lee, Mar 1988 (UF 470338); 3 paratypes: 2 spec., 6.1 x 2.2 & 6.7 x 2.3 mm, from type locality, scallop boats! H.G. Lee, Mar 1988 (UF 470339); 1 spec., 7.7 x 2.8 mm, ex batfish, 80 km off St. Johns Co., E Florida, scallop boats! H.G. Lee, 3 Dec 1988 (USNM 900147).

Type locality. 80–97 km E of Ponte Vedra, St. Johns Co., E Florida, in 40–46 m depths, as related by the scallop fishermen to H.G. Lee.

Other material examined. A single additional specimen was examined: 6.5 x 2.3 mm, in 61–76 m, off Breakers Hotel, Palm Beach, Palm Beach Co., E Florida, McGinty! aboard R/V Triton , 25 Jul 1941 (UF 262314).

Range and habitat. E Florida (off St. Johns Co.; off Palm Beach Co.). Reported from 40–76 m depths. It is assumed that batfish (the source of most of the specimens) are not far-ranging, that the area of their capture is on or close to their feeding grounds, which is the shallower depth in the range (40 m).

Description. Shell very small (to 7.7 mm in total length), glossy, fusiform, with a truncated anterior; whorls slightly convex, their peripheries near the suture of succeeding whorl and as such appear to “sag”; up to 7 whorls total, the last 54% of total shell length. Sculpture of low broad ribs; aperture narrowly oval, anterior canal short, wide. Protoconch of 1¾ round, disproportionately large, smooth whorls, the first partially immersed in the second, the shell apex to appearing blunt. Axial sculpture of much reduced, low, broad, slightly opisthocline, round-crested ribs that stretch from suture-to-suture on spire whorls and evanesce just below periphery of last whorl. Ribs number 9–11 on penultimate and 4–6 on last whorl to varix, are recurved in sulcus. Intercostal spaces are about equal to rib widths and bear growth striae. Varix a broad low bulge positioned approximately ⅓- to ½-whorl from edge of outer lip. Spiral sculpture absent. Sulcus absent; slightly recurved ribs and growth striae below the suture mark past positions of the anal sinus. Outer lip thin, rather wide and smooth from the varix to lip edge but for a single strong axial fold just behind the anal sinus that might be mistaken for a varix. Edge of outer lip, together with anal sinus trace a smooth curve resembling a reversed “S”. Stromboid notch not present on examined specimens. Anal sinus a deep notch, apex round, outside edge divergent. Inner lip narrow, margined, recumbent, except for the anterior end which is erect and projects a little beyond the columella. A weak callus is present at the posterior end. Anterior canal short, open, end unnotched, or only slightly so; fasciole not swollen and without spiral sculpture; growth striae present. Color a light tan, rib crests lighter.

Remarks. Taxonomy. Lissodrillia levis , new species has the combination of characters unique to Lissodrillia : a small glossy shell with ribs that extend from suture-to-suture on spire whorls (sulcus weak), a short anterior canal, outer edge of anal sinus divergent, and no spiral sculpture. Variability. Five specimens have an average total length of 6.74 mm (6.1–7.7 mm) and an average W/ L ratio of 0.359. No remarkable variation in color or form is present in the examined specimens. Identification. Lissodrillia levis is similar to L. lactea , new species, which is found just south of the known range of L. levis , and to L. schroederi (Bartsch & Rehder, 1939) and L. simpsoni (Dall, 1887) from the west coast of Florida. From L. lactea it differs in possessing lower, fewer ribs that have their peripheries well below the mid-point of the whorl, and a proportionally larger protoconch. It is also a different color, tan not white. From L. schroederi and L. simpsoni it differs in being larger (6.74 mm total average length versus 5.16 and 5.69 mm for L. schroederi and L. simpsoni , respectively), in having less well defined ribs, and a different color—tan versus white or pink.

Etymology. The Plain Lissodrillia , from the Latin adjective levis (masculine or feminine), which can mean smooth, plain, or polished.

Figures

PLATE 125. Lissodrillia levis, new species. Figs. 1 – 3: holotype, E of Ponte Vedra, St. Johns Co., E Florida (UF 470338). 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. Figs. 4 – 6: paratypes, all from the type locality. Fig. 4: USNM 900147; Figs. 5 – 6: UF 470339. Fig. 7: off Palm Beach Co., E Florida (UF 262314).