Syntomodrillia lyra, 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 : 335-337

Syntomodrillia lyra , new species

( Plate 173 )

Type material. Holotype 8.1 x 3.2 mm (UF 170340); 2 paratypes from the type locality: 7.9 x 2.7 & 8.5 x 2.8 mm (UF 497106). All types R. Black! aboard M/V Ike, 15 Apr 1957.

Type locality. ENE of Contoy Light, Contoy I., Quintana Roo, Mexico, in 80 fms [146 m].

Range and habitat. Known only from the type locality.

Description. Shell very small (to 8.5 mm in total length) fusiform, truncated anteriorly, glossy, translucent; up to 8¼ convex whorls, the last approximately 58% of total length; sulcus convex, a cord-like swelling at suture. Axial ribs the predominant sculptural element, spiral threads between; aperture narrowly oval, a little wider than the anal sinus and anterior canal, the latter short. Protoconch of 2 round, glassy-smooth translucent whorls, the tip of the first partially immersed in the second. Axial sculpture of numerous narrow ribs, as wide as intercostal spaces, that stretch from suture-to-suture, and to the anterior fasciole on last whorl. Ribs end at the suture in a swelling, have round crests, number 11–12 on penultimate, and 8 on last whorl to varix. Varix narrow, glossy, positioned about ⅓-turn from edge of outer lip. Spiral sculpture of heavy threads between axials, about 14 on whorl base from suture to anterior fasciole, and an additional 6–9 are on the fasciole. Threads do not override the ribs. Sulcus convex, rope-like, bordering the suture with swellings at rib ends, unusual for the genus. Outer lip thin, with 5 strengthening folds; edge traces a relatively flat arc from anal sinus to stromboid notch, the latter the point of inflection of anterior canal. Anal sinus a deep notch close to suture, sides of sinus parallel, apex rounded; inner edge of sinus flared out by an outward bend of the outer lip. Inner lip erect at and projecting slightly beyond columella anteriorly, recumbent elsewhere; moderately wide, margined; posteriorly formed into a low parietal callus beside the anal sinus. Anterior canal moderately long, open, bent slightly to the right when viewed ventrally. Anterior fasciole not swollen; spiral threads on fasciole number 6–9. Color white or pink; some darker pigmented material of the animal shows through the translucent protoconch and early teleoconch whorls.

Remarks. Taxonomy. Syntomodrillia lyra has the combination of characters that are unique to Syntomodrillia : a small, slender, glossy shell with a moderately long anterior canal, ribs that extend from suture-to-suture, to anterior fasciole on last whorl, and spiral threads between ribs. This species is unique on account of its rather strong spiral threads, and convex, rope-like sulcus. Variability. The average total length of three specimens is 8.17 mm (7.9–8.5 mm) and their average W/ L ratio is 0.355. Fresh specimens are likely a translucent pink (as represented by the paratypes) and possibly white; long dead shells, such as the holotype, which has two large bore holes, may have whitened with age. Identification. At first, S. lyra might be mistaken for a species of Calliclava on account of its swollen sulcus and strong intercostal spiral threads, but members of that genus have a keeled protoconch, not a smooth one as in S. lyra . Also, its rather strong spiral threads are reminiscent of Clathrodrillia , but spiral elements of that genus override or cut the axials. They are present only between the axials in S. lyra . Among its congeners, S.

lyra is somewhat like S. portoricana , new name, a little larger and with stronger spiral threads. Whorl peripheries are more anterior in S. portoricana .

Etymology. The Lyre Syntomodrillia , from the Latin noun for lyre— lyra . The row of strong spiral threads on the dorsum of the last whorl suggests a row of lyre strings.

Figures

PLATE 173 Syntomodrillia lyra, new species. Figs. 1 – 3: holotype, ENE of Contoy Light, Quintana Roo, Mexico (UF 170340). 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 – 5: paratypes from same lot as holotype, ventral views (UF 497106).