Fenimorea biminensis, 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 : 150-151

Fenimorea biminensis , new species

( Plate 68 )

Type material. Holotype 10.5 x 4.1 mm, R. Robertson! 1957 (ANSP 329613); no paratypes.

Type locality. 7 mi [11 km] ESE of Great Isaac, Bimini Is., Bahama Is. Depth not stated.

Range and habitat. Known only from the holotype.

Description. Shell small, to 10.5 mm in total length, fusiform, truncated anteriorly, of up to 8¼ slightly convex whorls, the last 58% of shell length. Aperture a narrow oval with a distinct anal sinus posteriorly and short, open anterior canal. Protoconch smooth, of approximately 1¾–1⅞ round whorls, the first not immersed in the second. Axial sculpture of low broad ribs that extend from suture-to-suture, lower in the anal sulcus, and evanesce at the anterior fasciole on the last whorl; 13 on penultimate whorl and 11 on last whorl to varix. Varix hump-like, about ⅓-turn back from the edge of the outer lip. Spiral sculpture of closely spaced microscopic incised lines over the shell surface, more widely spaced on the shell base, cut by closely spaced growth striae that form microscopic pits between. Sulcus demarcated by a crease on the shell surface, ribs reduced in height. Outer lip thin, its edge forming a rather flat arc from the anal sinus to tip of the anterior canal; with about 5 tiny “teeth” along its edge that are projections of the deeper, more widely spaced spirals. Two thick axial folds near lip edge. Anal sinus deep, apex round, sides straight; slightly constricted at opening on parietal wall side by a callus. Anterior canal very short, open, slightly notched at its tip; anterior fasciole not swollen; spirals about the same as on shell base. Inner lip recumbent, thick on columella, narrow, margined, glossy thin on parietal wall, and formed into an elongate lobe at the anal sinus. Color white with a wide, unbroken light brown spiral band mid-body, with the same color variably in intercostal space to suture; large darker brown patch on the center of the varix and irregularly on shoulders. Spire tip and anterior canal white.

Remarks. Taxonomy. Fenimorea biminensis has all of the characteristics of Fenimorea : shell microsculpture typical of the genus; ribs suture-to-suture that are modified in the sulcus, a broad hump-like varix; a deep U-shaped anal sinus, and numerous low ribs. It is believed to be closely allied to other small members of the genus. Identification. Fenimorea biminensis is similar in size and shape to F. caysalensis , new species, F. jongreenlawi , new species, and F. glennduffyi , new species. The average total length of the three latter species (10.52, 10.87, and 11.1 mm, respectively) is comparable to 10.5 mm, the length of F. biminensis ; however, other shell parameters differ. Fenimorea caysalensis has a stouter shell, more axial ribs, and a shell spire with an acuminate tip lacking in F. biminensis . Fenimorea jongreenlawi lacks minute “teeth” on its outter lip edge, has a paler spiral band, and also has a slightly acuminate spire that is lacking in F. biminensis . Fenimorea glennduffyi has a narrower shell (W/L = 0.390 versus 0.418), and a narrower mid-whorl brown spiral band. From F. fabae , new species F. biminensis differs in possessing distinct ribs, spiral grooves, teeth on the outer lip edge, and a distinct sulcus, all of which are lacking in F. fabae . From F. culexensis Usticke, 1969 it differs in possessing a round last whorl, not a somewhat square one, a less angular shoulder, and has a different color pattern.

The single type specimen is believed to be distinctive enough to separate it from similar congeners, as described above, to merit its description as a new species. In addition to being distinctively different among the small species from localities on the Great Bahama Bank ( F. caysalensis and F. fabae , as described above), it is also distinctly different from known dwarf ecomorphs of F. fucata (Reeve, 1845) from Andros Island, which is located on the same bank (see Plate 79 ).

Etymology. The Bimini Fenimorea . Named for the type location.

Figures

PLATE 68. Fenimorea biminensis, new species. Figs. 1 – 3: holotype, ESE of Great Isaac, Bimini Is., Bahama Is. (ANSP 329613). 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.

PLATE 79. Fenimorea fucata (Reeve, 1945). Great Bahama Bank, Bahama Is. specimens. Figs. 1 – 6: Bimini Is. Fig. 1: S end, Cat Cay (author’s coll.); Figs. 2 – 3: Honeymoon Cove, Gun Cay (author’s coll.); Fig. 4: Cat Cay (author’s coll.); Figs 5 – 6: S. Bimini I. (UF 359553 & UF 359489, respectively). Figs. 7 – 13: Andros I. Figs. 7 – 8: Small Hope Bay (DMNH 41349); Figs. 9 – 10: Fresh Creek, Long Cay (EFG 11555); Fig. 11: off Long Cay (author’s coll.); Figs. 12 – 13: Small Hope Bay (DMNH 41349). Figs. 14 – 19: New Providence I.: off Paradise I., Nassau (author’s coll.). Figs. 20 – 23: Eleuthera I. Fig. 20: Current (UF 470303); Fig. 21: off Cape Eleuthera (author’s coll.); Figs. 22 – 23: N of Current Cut, Current (UF 470303). Figs. 24 – 26: Mayaguana I.: SW end, Booby Cay (author’s coll.).