Fenimorea alba, 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 : 148-149

Fenimorea alba , new species

( Plate 67 )

Type material. Holotype 18.2 x 7.3 mm (USNM 1291342); 7 paratypes: 2 spec., 18.8 x 7.4 & 18.5 x 7.2 mm, off Farallon Is., NE of Portobelo, Colón Prov., Panama, 09°05'N, 80°01'W (EFG 30519); and 2 spec., 15.6 x 6.0 & 14.3 x 6.3 mm, Outer Duarte Cay, Colón Prov., Panama (author’s coll.); 2 spec.: 21.2 x 8.2 & 17.4 x 6.8 mm, in 60– 80 m, off Porto Bello Bay, Colón Prov., Panama, J. Ernest! Jun 2004 (P. Stahlschmidt coll.); 1 spec., 15.0 x 6.2 mm, Escudo de Veraguas I., Bocas del Toro Prov., Panama (ANSP 464991).

Type locality. Off Portobelo, Colón Prov., Panama, in 18– 61 m.

Range and habitat. Caribbean Panama (Bocas del Toro Prov.; off Colón Prov.). Reported at 10– 80 m.

Description. Shell small (to 21.2 mm in total length), broadly fusiform, truncated anteriorly; early whorls nearly flat, convex and well shouldered below the sulcus on last 4, number up to 9½, the last 50% of total shell length; surface matte, not glossy, predominant sculpture of numerous low axial ribs; aperture narrowly oval. Protoconch eroded on type material; number of whorls indeterminate. Axial sculpture of numerous convex ribs, 12–17 on the penultimate, 8–15 on last whorl to varix, which extend from whorl to whorl on the spire and evanesce on shell base near anterior fasciole. Ribs are low, somewhat irregular and narrower than their intercostal space, abruptly lower, narrower, and curved in anal sinus. Varix broad, low, hump-like, approximately ⅓-turn from edge of outer lip. Spiral sculpture of microscopic threads, separated by space 3–4 times their width, made jagged by the intersection of sub-equal growth striae between which are rectangular pits. More widely spiral grooves, up to about 11 on last whorl, overlay this pattern and end in “teeth” on edge of outer lip. Sulcus approximately ¼-whorl height on spire, demarcated by abrupt change in height of ribs, lower, narrower, curved, reflecting outline of anal sinus. Outer lip thin, flattened from varix to edge, which is nearly straight from anal sinus to the stromboid notch. Up to about 4 strengthening axial folds may be present; stromboid notch shallow. Anal sinus deeply notched, U-shaped, bounded by a parietal lobe on one side and outer lip, which is turned outward, on the other such that it appears spout-like; entrance slightly constricted. Inner lip narrow, margined, thickened and erect along anterior canal, thinner on parietal wall, and formed into a thick lobe posteriorly at sinus opening. Anterior canal short, open, turned slightly to the right when viewed ventrally; notched. Anterior fasciole with coarse spiral threads. Color white. No varical color patch is present on examined specimens.

Remarks. Taxonomy. Fenimorea alba has all the key characteristics of Fenimorea : the typical shell surface microsculpture, a hump-like varix, and ribs that run from suture-to-suture on spire whorls but are significantly and abruptly changed in the sulcus. Variability. The eight measured specimens are an average of 17.38 mm in total length (14.3–21.2 mm), and an average W/ L ratio of 0.400. Identification. Fenimorea alba is similar to the following all-white congeners: F. nivalis , new species, F. phasma (Schwengel, 1940) , and F. marmarina (Watson, 1881) . From F. nivalis it differs in being larger, possessing ribs that are more convex, having a stouter shell, and a narrower inner lip. From F. phasma it differs in being smaller. From F. marmarina it differs in having narrower ribs with round, not ridged crests.

Etymology. The White Fenimorea , named for the characteristic color of the species; alba is the feminine form of the Latin adjective albus, meaning white.

Figures

PLATE 67. Fenimorea alba, new species. Upper panel. Figs. 1 – 3: holotype, off Portobelo, Colón Prov., Panama (USNM 1291342). Fig. 1: ventral, lateral, and dorsal views; Fig. 2: enlarged view of protoconch (not to scale); Fig. 3: apical view, V = varix, L = edge of outer lip. Lower panel, paratypes, all from Panama. Fig. 4: off Porto Bello Bay, Colón Prov. (P. Stahlschmidt coll.); Figs. 5 – 6: off Farallon Is., Colón Prov. (EFG 30519); Fig. 7: Escudo de Veraguas I., Bocas del Toro Prov. (ANSP 464991); Figs. 8 – 9: Outer Duarte Cay, Colón Prov. (author’s coll.).