Fenimorea nivalis, 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 : 188-190

Fenimorea nivalis , new species

( Plate 89 )

Type material. Holotype 12.7 x 5.2 mm (MZSP 122067); 9 paratypes: 2 spec., 10.5 x 4.7 & 12.9 x 5.7 mm, off Rio Grande do Norte, Brazil (UF 470315); 1 spec., 16.7 x 6.3 mm, in 3–5 m, 3 Pedras I., Guarapari, Espirito Santo, Brazil, A. Jorio! (MNRJ 34637); 6 spec., 11.2 x 4.8 & 14.0 x 5.5 mm (BMSM 14991), 10.7 x 4.3, 11.4 x 4.6, 10.2 x 4.4 & 10.1 x 4.3 mm (ANSP 464963), by shrimper at 100 m, off Cabo Frio, Rio de Janeiro, Brazil.

Type locality. Off Cabo Frio, Rio de Janeiro, Brazil, in 100 m.

Range and habitat. Bahama Is. (Exuma Cays); Dominican Republic; Puerto Rico; Brazil (Rio Grande do Norte; Espirito Santo; Rio de Janeiro). Reported from 1.2– 100 m.

Description. Shell small (to 16.7 mm total length), biconic, surface dull, not glossy; whorls number up to 8½ total, slightly convex with appressed suture, the last whorl 63% of total length. Shell sculpture of low axial ribs; aperture narrowly oval. Protoconch of 1½ round glossy whorls, the first not immersed in the second. Axial sculpture of low, narrow, straight ribs with round crests, intercostal spaces greater than their width, that extend from suture-to-suture on spire whorls and evanesce at the anterior fasciole on the last. Ribs slightly recurved and lower in sulcus; number 13–16 on penultimate, and 8–13 on last to varix. Varix low, broad, hump-like, positioned about ⅓-turn from edge of outer lip. Spiral sculpture of very fine microscopic threads throughout and more widely spaced shallow grooves, the latter, visible on the last whorl, end in dimples and a few more elongate projections or “teeth” on edge of outer lip. Fine threads are intersected by sub-equal but more closely packed growth striae forming aligned rows of narrow elongate “pits” between the threads. Threads are heavier on shell base near and on anterior fasciole. Sulcus wide, about ⅓-whorl height, marked by lower, recurved ribs and growth striae. Microsculpture the same as on whorl face. Outer lip thin, with up to 5 regularly spaced axial folds similar to the ribs in shape and spacing, and the same microsculpture. Lip edge traces a low arc from anal sinus to anterior canal, with no stromboid notch. Anal sinus is a deep U-shaped notch close to the suture on the whorl’s shoulder. Inner lip thick, margined, “pinched” erect on the anterior canal, recumbent elsewhere, wide along columella, narrowing on parietal wall, and ending in an elongate, heavily enameled lobe at the anal sinus. Anterior canal short, open, with a slight notch at its end; fasciole not swollen. Color white; iron staining on shell base of some individuals.

Remarks. Taxonomy. Fenimorea nivalis has the characteristics of Fenimorea : numerous low ribs suture-tosuture, changed in the sulcus, a hump-like varix, and the typical shell microsculpture of fine threads and dense growth striae that create rows of narrow “pits”. Variability. The average total length of 10 specimens is 12.04 mm (10.1–16.7 mm) and their average W/ L ratio is 0.416. Identification. Fenimorea nivalis is close in appearance to F. jongreenlawi , new species, and F. alba , new species. From F. jongreenlawi it differs by its all-white shell, and by the presence of spiral grooves and minute projections and dimples on the edge of its lip. Fenimorera jongreenlawi has a smooth lip edge. From F. alba it differs in being smaller (12.04 versus 17.38 mm average total length), in possessing ribs that are less convex, and in having a wider inner lip.

Etymology. The Snowy Fenimorea , from the Latin adjective nivalis meaning snowy or snow-like.

Figures

PLATE 89. Fenimorea nivalis, new species. Figs. 1 – 3: holotype, off Cabo Frio, Rio de Janeiro, Brazil (MZSP 122067). 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. Fig. 4: off Rio Grande do Norte, Brazil (UF 470315); Figs. 5 – 10: off Cabo Frio, Rio de Janeiro, Brazil. Figs. 5 – 6: BMSM 14991; Figs. 7 – 10: ANSP 464963.