Fenimorea elongata, 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 : 161-162

Fenimorea elongata , new species

( Plate 75 )

Type material. Holotype 25.0 x 7.4 mm, D. Steger! (UF 155626); one paratype: 18.4 x 6.0 mm, SW of Cape San Blas, Gulf Co., W Florida, in 125 fms [229 m] depth (UF 158188).

Type locality. 130 mi [209 km] SW of Egmont Key, Hillsborough Co., W Florida, in 70 fms [128 m].

Range and habitat. Eastern Gulf of Mexico, (off Gulf Co.; off Hillsborough Co.) in 128– 229 m.

Description. Shell medium sized (to 25.0 mm), fusiform, truncated anteriorly, spire quite tall for genus, up to 11¼ slightly convex whorls overall, suture undulates over ribs of preceding whorl, last whorl approximately 47% of total length. Aperture narrow, about as wide as the short open anterior canal anteriorly; with a deep notch posteriorly. Protoconch of approximately 1½ smooth, glossy, round whorls. Axial sculpture of strong straight ribs that extend from suture-to-suture that tend to align whorl-to-whorl, 7–9 on the penultimate, 5–6 to the varix on last whorl where they evanesce on the ventral surface before the anterior fasciole but extend to the fasciole on the dorsal surface. Varix an expanded rib about ¼- to ⅓-turn from the edge of the outer lip. Spiral sculpture lacking; shell surface microsculpture of fine, wavy, incised lines, sometimes obsolete near the suture, that are intersected by growth striae, producing rows of pits between. Sulcus absent, ribs are very slightly recurved, but not diminished below the suture. Outer lip thin, flattened from varix to its edge, with a strong fold (on the holotype) just posterior of the anal sinus. Lip edge forms a low arc from anal sinus to anterior canal; is folded inward from anal sinus, then anteriorly for about ½ the length of the lip. Stromboid notch close to anterior end of anterior siphon, very weak. Anal sinus deeply notched, U-shaped and offset laterally a little from the shell axis by the parietal lobe. Inner lip thin, unemarginate in parietal area, slightly erect on anterior canal, formed into a parietal lobe posteriorly. Anterior canal short, open, and a shallow notch. Anterior fasciole with the same microsculpture as shell. Color uniformly beige-white with a narrow pale-pink diffuse band between ribs, and a yellow hue on varix and columella.

Remarks. Taxonomy. Fenimorea elongata possess the shell surface microsculpture typical of Fenimorea , ribs that extend from suture-to-suture, and a deep U-shaped anal sinus. Its lack of a distinct sulcus seems to typify offshore, deeper-water species, which it is, as well as the erect, expanded rib, not hump-like varix (see under key characteristics in the introduction to Fenimorea ). Identification. Fenimorea elongata is similar to F. pagodula (Dall, 1889) , and F. petiti Tippett, 1995 . It differs from F. pagodula in possessing whorls that are slightly more convex and more evenly so. The whorls of F. pagodula have peripheries below mid-whorl. The last whorl of F. elongata is straighter in profile, not angled to the right when viewed ventrally as in F. pagodula . The base color of F. elongata is a similar beige-white but has a diffuse pinkish band confined to intercostal space, not the better defined pale yellow to brownish yellow band that tends to override the ribs exhibited by F. pagodula . Fenimorea elongata also differs from F. pagodula in possessing a narrower shell (W/ L ratio = 0.311 versus 0.326), and may prove to be a slightly larger species (to 25.0 versus 22.3 mm maximum length). Fenimorea petiti differs from F. elongata in possessing more convex ribs, a shorter spire and broader shell, and a more distinct mid-whorl color band. The characteristics that separate F. elongata from F. petiti and F. pagodula , as described above, are sufficiently distinct to merit description of the specimen as new. None of the examined specimens from over what is believed to be most of the range of F. petiti have the elongate form or coloration of F. elongata . Fenimorea elongata differs from F. pagodula in more subtle but important ways (whorl profile, shape, color, and size), which are nonetheless believed to add up to a true species, not a variant of F. pagodula .

Etymology. The Elongated Fenimorea , referring to the unusually high spire of the species. Derived from the Latin verb elongo ( elongata = perfect passive participle, nominative single feminine).

Figures

PLATE 75. Fenimorea elongata, new species. Figs. 1 – 2: holotype, SW of Egmont Key, Hillsborough Co., W Florida (UF 155626). Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged views of protoconch (not to scale). Figs. 3 – 4: paratype, SW of Cape San Blas, Gulf Co., W Florida (UF 158188). Fig. 3: ventral view; Fig. 4: apical view, V = varix, L = edge of outer lip.