Fenimorea abscondita, 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 : 146-148

Fenimorea abscondita , new species

( Plate 66 )

Type material. Holotype 35.75 x 12.9 mm, J. Moore! (AMNH 191358); 10 paratypes: 1 spec., 30.5 x 11.6 mm, in 46 m, WSW of John’s Pass, Pinellas Co. (DMNH 107775); 1 spec., 27.9 x 10.6 mm, in about 40 m, 75 km NNW of Egmont Key, Hillsborough Co., 27°40.23'N, 83°31'W, E. García! aboard R/V Pelican, 13 Aug 1994 (EFG 14090); 2 spec., 35.4 x 12.4 & 28.0 x 11.3 mm in 23 m, 45 km W of Egmont Key, Hillsborough Co., 27°37'N; 83°13'W, E. García! aboard R/V Pelican, 28 Jun 1993 (EFG 12953); 4 spec. 27.5 x 10.7, 24.5 x 8.7, 32.4 x 12.1 & 20.0 x 7.7 mm, in 55 m, off Naples, Collier Co. (UF 170844); 1 spec., 31.0 x 11.1 mm, 85 mi [137 km] W of Marco I., Collier Co. (author’s coll.). 1 spec., 28.1 x 10.5 mm, in 90–120 ft [27–37 m], Briar Reef, SW of Cedar Keys, Levy Co., W Florida, J. Moore! 1967 (AMNH 138459).

Type locality. Off W Florida, Gulf of Mexico, in 150 ft [46 m].

Range and habitat. W Florida (off Levy, Pinellas, Hillsborough, Naples & Collier Counties). Reported from 23– 46 m.

Description. Shell medium (to 35.8 mm in total length), fusiform, truncated anteriorly, surface glossy with a high spire, whorls with appressed sutures, concave at sulcus, convex below sulcus; whorls number up to 11¼, the last approximately 55.5% of the total shell length. Predominant sculpture is ribs; aperture narrow. Protoconch of approximately 2 smooth round whorls. Axial sculpture of narrow opisthocline ribs that extend from suture-tosuture on spire whorls and evanesce on shell base, most disappearing well before the anterior fasciole on the ventral side but not on the dorsum. Ribs reduced and slightly recurved in sulcus, are narrower than intercostal spaces and number 10–11 on the penultimate and 7–10 on the last whorl to the varix. Varix large, hump-like, positioned ¼- to ⅓-turn from edge of outer lip. Spiral sculpture of ridges on shell base, becoming stronger on anterior canal; shell surface microsculpture of spiral grooves, fairly widely spaced, intersected by growth striae forming small pits, a characteristic of the genus. Sulcus about ¼-whorl height, with much reduced, recurved ribs. Spiral grooves closer, growth striae also recurved. Outer lip thin, flattened from varix, with weak axial folds; edge of lip forms a low arc from anal sinus to anterior canal; stromboid notch a weak indentation. Anal sinus a deep, U-shaped notch; inner edge flared in mature shells, and directed laterally spout-like. Inner lip detached and raised anteriorly, recumbent and moderately wide on columella, narrower on parietal wall; formed into a heavy lobe on the parietal wall at the anal sinus. Anterior canal short, open, straight, deeply notched; anterior fasciole heavy in older individuals, but not swollen. Color uniformly beige with three orange bands: one the shoulder, at the periphery and on the shell base. The peripheral band tends to be the widest and darkest, the basal one the lightest.

Remarks. Taxonomy. Fenimorea abscondita has the characteristic microsculpture of Fenimorea , axial ribs that extend from suture-to-suture on spire whorls that are interrupted by an abrupt reduction of the ribs in the sulcus, a hump-like varix present approximately ⅓-turn from the edge of the outer lip, and a short, open anterior canal. Variability. The average total length of 10 specimens is 29.19 mm (20.0– 35.75 mm); their average W/ L ratio is 0.374. Identification. Fenimoreaa abscondita is very similar to and may be confused with F. moseri (Dall, 1889) . Fully developed specimens are usually larger (29.19 versus 20.97 mm average total length) and have more angular shoulders. Examined specimens are uniformly beige with orange spiral color bands, whereas F. moseri is usually monochromatic. Fenimorea abscondita appears to be sympatric with F. moseri but so far reported from a narrower bathymetric range of 23– 46 m. F. mos eri has the wider depth range of 0.2–126 m, the shallower depths (0.2–4 m) for the white form of the Florida Keys. While F. abscondita is very similar to F. moseri , consistent morphological differences in size, color, and whorl profile merit its placement in a separate species. Fenimorea abscondita is similar to F. pagodula (Dall, 1889) , F. petiti Tippett, 1995 , and Clathrodrillia wolfei Tippett, 1995 . It differs from F. pagodula in having a shorter spire, stouter shell, more convex whorls, and in lacking a dull yellow color band. From F. petiti it differs in being larger (average total length is 29.30 versus 12.11 mm), having a wider sulcus, more angular shoulders, and is colored differently. From C. wolfei it differs in being larger (29.30 versus 12.71 mm average total length), stockier, in possessing a different microsculpture, and a shorter anterior canal.

Etymology. The hidden Fenimorea , from the Latin adjective absconditus meaning hidden, concealed. This species was found among lots of Fenimorea moseri (Dall, 1889) , for which it is easily mistaken, in museums and in private collections.

Figures

PLATE 66. Fenimorea abscondita, new species. Upper panel. Figs. 1 – 3: holotype, off W Florida, Gulf of Mexico (AMNH 191358). Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged views of protoconch (not to scale); Fig. 3: apical view, V = varix, L = edge of outer lip. Lower panel. Figs. 4 – 10: paratypes. Fig. 4: W of Egmont Key, Hillsborough Co. W Florida (EFG 12953); Fig. 5: off Naples, Collier Co., W Florida (UF 170844); Fig. 6: W of Marco I., Collier Co., W Florida (author’s coll.); Fig. 7: WSW of Johns Pass, Pinellas Co., W Florida (DMNH 107775); Fig. 8: off Naples, Collier Co., W Florida (UF 170844); Fig. 9: NNW of Egmont Key, Hillsborough Co., W Florida (EFG 14090); Fig. 10: off Naples, Collier Co., W Florida (UF 170844).