Leptadrillia Woodring, 1928

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 : 213

Genus Leptadrillia Woodring, 1928

Type species: Turris (Surcula) parkeri Gabb, 1873 by original designation (Pliocene, Dominican Republic and Jamaica).

Diagnosis. According to Woodring (1928: 159–160), shell glossy, very slender with a narrow aperture and long, narrow anterior canal with a very shallow notch. Protoconch of approximately 2 smooth whorls, the last slightly bulging. Teleoconch whorls slightly convex, suture appressed; sculpture of narrow ribs that extend from suture-tosuture on the spire, and to the columella on the body whorl, only slightly reduced and recurved in the area of the anal fasciole. Varix set back a distance from the anal sinus. Spiral sculpture mostly absent, limited to threads or ridges on the anterior fasciole. Anal sinus near suture, U-shaped, wide; stromboid notch shallow. Inner lip narrow, edge detached; with a heavy callus on the parietal wall at the anal sinus.

Key characteristics. The combination of the following characteristics distinguishes Leptadrillia from other TWA drilliid genera:

1. Shell small, glossy, usually less than 15 mm, slender (range of average species W/ L ratio = 0.308–0.360) with a narrow aperture and long anterior canal;

2. Ribs almost always extend from suture-to-suture and to anterior fasciole on last whorl, slightly reduced and recurved on whorl shoulders;

3. Shell surface smooth, spiral sculpture limited to ridges or threads on and sometimes near anterior fasciole; and

4. Varix rib-like, but wider and higher; positioned approximately ¼–½-turn from the edge of the outer lip, i.e., not visible when shell is viewed ventrally.

Similar genera. Syntomodrillia Woodring, 1928 is also glossy with ribs suture-to-suture except that it has spiral grooves or threads between ribs, a shorter anterior canal, and a wider aperture. Threads or grooves may be very faint or even variably absent in some species of Syntomodrillia , but the shorter anterior canal will often distinguish members of this genus. Splendrillia Hedley, 1922 differs in possessing a short anterior canal, ribs that only extend to the sulcus not to the suture, and a hump-like varix.

Distribution. Leptadrillia is distributed throughout the TWA on soft bottoms in moderately deep (50 m) to bathyal depths. Species ranges are poorly known because of their scarcity in collections and because of the unreliability of identifications in published accounts. Confirmed general localities of species treated in this work are shown in Plates 118–119.