Leptadrillia maryae, 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 : 227-228

Leptadrillia maryae , new species

( Plate 113 )

Type material. Holotype 7.9 x 2.8 mm, T. McCleery! Nov 2005, ex. coll. P. Stahlschmidt (SMF 336444). No paratypes.

Type locality. Rosario I., Cartagena Dept., Colombia, in 73– 165 m. Range and habitat. Known only from the holotype.

Description. Shell very small (7.9 mm in total length), narrowly fusiform (W/L = 0.354), glossy and translucent; whorls moderately convex with peripheries just below mid-whorl, 9¼ in number, the last approximately 56% of total length; aperture narrow, anal sinus and anterior canal only slightly narrower; sculpture of axial ribs. Protoconch of approximately 3 smooth round translucent whorls. Axial sculpture of strong, broad, slightly opisthocline ribs that run suture-to-suture and evanesce before the anterior fasciole on shell base, widest mid-whorl; lower, narrower, and slightly curved on shoulder; 10 on penultimate, 7 on body whorl to varix with intercostal space about as wide as ribs. Vari x strong, larger and less oblique than preceding ribs; positioned about 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 lower, narrower and slightly recurved ribs. Outer lip thin, with 2 slender strengthening axial folds; lip edge flexed only slightly outward near the anal sinus, otherwise projecting out in a nearly circular arc from the anal sinus to stromboid notch; stromboid notch shallow and wide. Anal sinus deep, U-shaped, offset from the axis of the shell by the parietal wall and lobe and slight outward flex of the outer lip near the sinus such that it appears spout-like. Inner lip narrow, recumbent, margined; thicker on the anterior portion of the columella, developed into a weak parietal lobe posteriorly. Anterior canal long, open, turned right at its end when viewed ventrally, unnotched; fasciole not swollen, spiral threads present. Color of shell pale golden brown, ribs, anterior canal and outer lip lighter.

Remarks. Taxonomy. Leptadrillia maryae has all of the distinguishing characteristics of the genus: a narrow fusiform shell with a long anterior canal, ribs that extend from suture-to-suture, without a sulcus, and the absence of spiral sculpture except for spiral grooves near or on the anterior fasciole. Identification. Leptadrillia maryae is most similar in shape to L. incarnata , new species, but is smaller and differently colored. It resembles L. loria Bartsch, 1934 but has a 3-whorl versus 1¾-whorl protoconch, and straighter ribs. It may also be mistaken for Syntomodrillia hesperia , new species or Syntomodrillia stahlschmidti , new species from the same region, but may be most readily differentiated by the absence of spiral grooves between ribs.

This single specimen is believed to merit description as new on account of morphological differences of protoconch whorl count of its two closest congeners, L. incarnata and L loria (3 versus 2 and 1¾, respectively), size, and color. The size range of the L. incarnata is 8.8–14.1 mm, which is larger that the 7.9 mm length of L. maryae . L loria is only 6.8 mm.

Etymology. Mary’s Leptadrillia , named after my wife, my life companion, and best friend.

Figures

PLATE 113. Leptadrillia maryae, new species. Figs. 1 – 3: holotype, Rosario I., Cartagena Dept., Colombia (SMF 336444). Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged views of protoconch (not to scale); Fig. 3: apical view, V = varix, L = edge of outer lip.