Fenimorea tessellata, 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 : 206-208

Fenimorea tessellata , new species

( Plate 99 )

Types. Holotype 35.2 x 14.2 mm (UF 156611); 8 paratypes: 1 spec., 26.9 x 11.0 mm, Gulf of Mexico, J. Moore! (USNM 900217); 1 spec., 39.4 x 14.5 mm, in 126 m, W Gulf of Mexico, D. Steger! (DMNH 175343); 1 spec. 32.2 x 12.0 mm, in 60 m, E of Palmas Point, Yucatan, Mexico, D. Steger! Oct 1953 (UF 156610); 1 spec., 19.8 x 6.8 mm, in 49–54 m, Campeche Bank off Yucatan, 22°19.42'N, 90°21.84'W, E. García! aboard R/V Pelican, 21 Jun 2005 (EFG 26028); 1 spec., 29.9 x 12.3 mm, in 52 m, off Tarpon Springs, Pinellas Co., W Florida, J. Moore! Oct 1965 (USNM 900218); 1 spec., 38.1 x 13.5 mm, in 183 m, off Egmont Key, Hillsborough Co., W Florida, J. Moore! 1961 (UF 156612); 2 spec., 38.5 x 14.5 & 16.2 x 6.4 mm, in 49 m, SW of Naples, Collier Co., M.E. Powlus! 18 Jul 1960 (UF 170843).

Type locality. Off Anna Maria Key, Manatee Co., W Florida in 55 m.

Other material examined. An additional 6 specimens were examined: Mexico: 1 spec., 29.7 x 10.8 mm, in 126 m, ENE of Alacran Reef, Campeche Bank, off Yucatan (DMNH 107814); 1 spec., 28.7 x 11.2 mm, in 49–52 m, 65 km WSW of Alacran Reef, off Yucatan, 22°18.39'N, 090°21.84'W, E. García! aboard R/V Pelican, 21 Jun 2005 (EFG 26240); 1 spec., 26.6 x 10.2 mm, Campeche Bank, off Campeche, W.M. Bass! Aug 1952 (UF 196252); 1 spec., 32.6 x 12.0 mm, in 93–94 m, ca. 20 km WSW of Triángulos Reef, Campeche Bank, off Campeche, 20°51.16'N, 92°26.28'W, E. García! aboard R/V Pelican, 10 Jun 2005 (EFG 26112). W Florida: 1 spec. 27.5 x 10.5 mm, in 46 m, WSW of Johns Pass, Pinellas Co., Steger! 1965 (ANSP 306249). E Florida: 1 spec., 24.8 x 9.8 mm, in 73 m, off Palm Beach, Palm Beach Co., McGinty! 8 Jun 1940 (UF 155666).

Range and habitat. Mexico (Campeche Bank: off Yucatan; off Campeche); W Florida (off Pinellas Co.; off Hillsborough Co.; off Manatee Co.; off Collier Co.). Reported from 4–210 m depths, most in the narrower range of 46– 126 m. A single specimen from off Palm Beach Co., E Florida may be this species (Pl. 99, Fig. 5).

Description. Shell medium (to 39.4 mm), fusiform, truncated anteriorly, up to 11¾ whorls, with a large body whorl approximately 56% of the shell’s length. Whorls turreted, nearly flat-sided, with a concave sulcus below the appressed suture. Protoconch of 2 smooth round whorls. Axial sculpture of numerous narrow ribs that appear to terminate at, but are greatly reduced and recurved in sulcus, and curved in toward anterior fasciole on shell base; 13–15 ribs on penultimate, 9–11 on body whorl to varix, crests narrow, not round; spaces between axials about same as width of axials. Varix narrow, not much wider than preceding rib, which sometimes runs into the varix; about ⅓-turn from outer lip edge. Spiral sculpture of microscopic fine jagged threads, with sub-equal intersecting growth striae, appearing very similar to that of F. f uc a t a —with “pits” appearing between the growth striae. In addition, overriding the microsculpture are widely spaced spiral grooves, about 11 on the body whorl. Sulcus concave, well demarcated by the abrupt change in the ribs, which become thinner and recurved. The microsculpture seen elsewhere on the shell is also present in the sulcus. Outer lip thin, thickened in older specimens, flattened from the varix to lip edge, with fine strengthening axial folds. Edge of lip, beginning just behind the anal sinus, forms a low arc from anal sinus to stromboid notch, is scalloped by projecting ends of spiral grooves and bent slightly inward near anal sinus. Stromboid notch shallow. Anal sinus a deep notch adjacent to suture posteriorly, set off at an angle from axis of shell by parietal callus anteriorly; flared inner rim of sinus and upward bend of outer lip causes sinus to appear spout-like. Inner lip detached anteriorly along canal, but reduced to a glaze in the parietal area. A large callus present posteriorly forming parietal side of the anal sinus. Anterior canal short, curved to the right viewed ventrally, notched at its tip. Anterior fasciole slightly swollen; without spiral grooves or cords, but with microsculpture like shell base. Color white with 4 reddish-brown spiral bands visible on the last whorl, posterior-most band with overlying darker patches of reddish-brown, especially in sulcus. Rib crests mostly white, thus bands are mostly confined to the interspaces. Some spiral grooves colored reddish-brown; varical hump with a large yellowish-brown patch.

Remarks. Taxonomy. Fenimorea tessellate has all the distinguishing characteristics of Fenimorea : a shell surface microsculpture of spiral threads and axial growth striae producing shallow “pits” in their interspaces, numerous low ribs that extend from suture-to-suture with the sulcus sharply demarcated on whorl shoulders, and a varix typical of other offshore members of the genus, narrow, not hump-like. Variability. The average length of 17 measured specimens is 29.20 mm (16.2–39.4 mm); their average W/ L ratio is 0.384. The size of specimens with fully developed lips ranges from 26.7 to 39.4 mm. Variability is seen in the color pattern, most strikingly in the lack of two white bands on the last whorl (Pl. 99, Fig. 9) and what is likely an all-white form (Pl. 99, Fig. 14). Identification. Fenimorea tessellata differs from F. fucata in its greater size and pattern of coloration. The random patches of brown on F. tessellata are mostly confined to the sulcus and do not “bleed” as far down into the rib interspaces as in F. fucata , but rather are confined to the margin of the band on the whorl’s shoulder. This latter species is rare in the Gulf, while F. tessellata appears to be largely confined to the Gulf. From the other large members of Fenimorea , F. j a ne t ae, F. kathyae , and F. sunderlandi it differs in having a more turreted profile (straighter sides), a scalloped lip edge, and a broader more distinct anal sulcus. The range of F. tessellata appears to only overlap that of F. sunderlandi , principally off W Florida. Although of a similar size to the F. janetae group, F. tessellata is more closely allied to F. fucata in shell shape and in coloration, if not in size.

Etymology. The Tessellate Fenimorea . Named for the mosaic pattern of its coloration (from tessellata, Latin for mosaic).

Figures

PLATE 99. Fenimorea tessellata, new species. Upper panel. Figs. 1 – 2: holotype, off Anna Maria Key, Manatee Co., W Florida (UF 156611). Fig. 1: ventral, lateral & dorsal views; Fig. 2: apical view, V = varix, L = edge of outer lip. Lower panel. Fig. 3: paratype, SW of Naples, Collier Co., W Florida (UF 170843); Fig. 4: paratype, Campeche Bank off Yucatan, Mexico (EFG 26028); Fig. 5: off Palm Beach, Palm Beach Co., E Florida (UF 155666); Fig. 6: paratype, 26.9 x 11.0 mm, Gulf of Mexico (USNM 900217); Fig. 7: WSW of St John’s Pass, Pinellas Co., W. Florida (ANSP 306249); Fig. 8: paratype, off Tarpon Springs, Pinellas Co., W Florida (USNM 900218); Fig. 9: ENE of Alacran Reef, Campeche Bank, Mexico (DMNH 107814); Fig. 10: paratype, W Gulf of Mexico (DMNH 175343); Fig. 11: paratype, SW of Naples, Collier Co., W Florida (UF 170843); Fig. 12: paratype, off Egmont Key, Hillsborough Co., W Florida (UF 156612); Fig. 13: paratype, E of Palmas Point, Yucatan, Mexico (UF 156610), Fig. 14: WSW of Triángulos Reef, Campeche Bank, Mexico (EFG 26112).