Fenimorea fabae, 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 : 162-164

Fenimorea fabae , new species

( Plates 65 , Figs. 5, 6 & Plate 76 )

Type. Holotype 10.1 x 4.4 mm (ANSP 370199); 15 paratypes originally from the same lot as the holotype, 9 measured: 10.4 x 4.5, 9.6 x 4.1, 10.4 x 4.7, 9.6 x 4.3, 10.3 x 4.4, 9.6 x 4.3, 10.0 x 4.6, 10.0 x 4.5 & 8.7 x 4.0 mm (ANSP 464999). All types, J. Worsfold!

Type locality. Caravel Beach (John Jack Point), Freeport, Grand Bahama I., Bahama Is., 26°29'30''N, 078°41'45''W, in shallow water.

Other material examined. An additional 18 specimens were examined: 1 spec., 8.3 x 3.6 mm, in 12 m, Kings Bay (Dundee Bay), Grand Bahama I., Bahama Is., 26°29'15"N, 078°43'30"W, J. Worsfold! (ANSP 373187); 14 spec., 8.2 x 3.8, 9.4 x 4.0, 9.0 x 4.0, 8.6 x 3.9, 9.1 x 3.9, 8.1 x 3.6, 8.4 x 3.7, 7.8 x 3.5, 8.5 x 3.7, 7.7 x 3.8, 8.3 x 3.6, 8.7 x 3.6, 7.5 x 3.6, 7.3 x 3.3 mm, in 9 m, Bahama Club slipway, Kings Bay Jetty, Kings Bay, Dundee Bay, Grand Bahama I., 26°29'15''N, 078°43'30''W, J. Worsfold! (ANSP 369088); 1 spec., 10.2 x 4.5 mm, in 11 m, Borco pipeline, 5 mi [8 km] W of Freeport, Grand Bahama I., 26°30'30''N, 078°46'30''W, J. Worsfold! Jun 1982 (ANSP 370942); 2 spec., 8.8 x 4.4 & 9.2 x 4.7 mm, in beach wash, Millar’s Beach, Eleuthera I., Bahama Is., M. Williams! 6 May 1998 (author’s coll.).

Range and habitat. Bahama Is. (Grand Bahama I.; Eleuthera I.), in shallow water to 12 m.

Description. Shell small (to 10.4 mm), bullet-shaped, of up to 7¾ impressed whorls, last whorl large, approximately 66% of total length. Spire short, slightly acuminate at its tip; whorls straight-sided except for sutural impressions, and slight creases marking the anterior boundary of the sulcus. Protoconch of 2 smooth glossy-white whorls. Axial sculpture of crowded minute ribs on the first 1½ whorls of the teleoconch, obsolete on the remaining whorls. Varix hump-like, approximately ¼- to ⅓-turn from the edge of the outer lip. Spiral sculpture absent; shell surface packed with microscopic growth striae and spiral incised lines, so close that under a dissecting microscope the shell’s surface appears velvety. Sulcus slightly convex, not excavated, but is marked by a slight spiral crease at its anterior margin. Outer lip thin, edge smooth, without scalloping, and without a stromboid notch. Lip edge, from the anal sinus to midway point flexed slightly into the aperture. Anal sinus is deep, round at its apex, lies next to the suture, except for the opening, which is skewed anteriorly by the parietal callus. Inner lip margined, and mostly a faint with a narrow wash of enamel; callus is present posteriorly on the parietal wall; columella is straight. Anterior canal is short, open, and slightly notched at its tip. Anterior fasciole not swollen; without spiral threads or ridges. Color white, with narrow orange-brown band below whorl periphery; patches on varical hump, and sporadically on whorls’ shoulder.

Remarks. Taxonomy. Fenimorea fabae is the most aberrant of the fucata -like species [ Fenimorea fucata (Reeve, 1845) ]. The characteristic shell microsculpture of Fenimorea is present but is compressed—spiral threads and growth striae are closer together producing a felt-like surface when viewed under a dissecting microscope. High magnification SEM photographs of the microsculpture of F. f a ba e are compared with similar photographs of F. janetae Bartsch, 1934 , and F. fucata (Reeve, 1845) in Plate 65 , two species that exhibit the typical pattern of the genus. The presence of axials from suture-to-suture, although only present on early teleoconch whorls, a varical hump, in addition to the typical shell microsculpture allies this species with Fenimorea . The near absence of axial ribs is probably a secondary loss, perhaps an environmental adaptation. Variability. The 26 measured specimens have an average total length of 8.99 mm (7.3–10.4 mm), and average W/ L ratio of 0.445. Identification. Fenimorea fabae resembles the dwarf ecotypes of F. f u c at a (Reeve, 1845) that have the same color pattern, which are also found on Grand Bahama I., but possesses axial ribs, a more distinct sulcus, a straight, not acuminate spire tip, and a less dense “ Fenimorea -like” microsculptural pattern. Dwarf specimens of F. f uc a t a are depicted in the plates included in that section. Fenimorea fabae is also similar to F. culexensis Usticke, 1969 , F. jongreenlawi , new species, F. caysalensis , new species, F. glennduffyi , new species, and F. biminensis , new species. It differs from F. culexensis in possessing a round last whorl, not square, in lacking fimbriations at the suture, and in having a different coloration. From F. jongreenlawi it differs in lacking ribs, a distinct sulcus, in being stockier, and in its color pattern. From F. caysalensis , F. glennduffyi , and F. biminensis it differs in lacking ribs, a distinct sulcus, and spiral grooves that end in “teeth” at the edge of the outer lip.

Etymology. The Bean Fenimorea , from the Latin noun fabae (feminine form) meaning resembling a bean. The small, squat smooth almost oval shell has inspired the name.

Figures

PLATE 65. Fenimorea spp. microsculpture: low and high magnification SEM images. Figs. 1 – 2. Fenimorea janetae Bartsch, 1934, Gold Rock, Great Bahama I., Bahama Is., 160 x & 1,410 x, respectively (ANSP 369721). Figs. 3 – 4. Fenimorea fucata (Reeve, 1845), North Hawksbill Creek, Grand Bahama I., Bahama Is., 235 x & 780 x, respectively (ANSP 370549). Figs. 5 – 6. Fenimorea fabae, new species, paratype, Freeport, Grand Bahama I., Bahama Is., 265 x & 2,600 x, respectively (ANSP 370199). All SEM images courtesy Paul Callomon, ANSP.

PLATE 76. Fenimorea fabae, new species. Upper panel. Fig. 1: holotype, Caravel Beach, Freeport, Grand Bahama I., Bahama Is. (ANSP 370199), ventral lateral & dorsal views. Lower panel. Figs. 2 – 10: paratypes from the type locality (ANSP 355001). Fig. 11 – 25: Kings Bay (Dundee Bay), Grand Bahama I., Bahama Is. Fig. 11: ANSP 373187; Figs. 12 – 25: ANSP 373188.