Calliclava tobagoensis, 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 : 49-51

Calliclava tobagoensis , new species

( Plate 18 )

Clathrodrillia tryonii auct. non (Dall, 1889): is a misidentification by Williams (2005; 2009: species 1546 [R photo pair only]) and likely this species.

Type material. Holotype 11.3 x 4.3 mm (USNM 1291324); 56 paratypes: 5 [of a total of 11] spec., 11.5 x 4.4, 11.4 x 4.1, 10.7 x 4.0, 9.8 x 3.8 & 9.2 x 3.6 mm, from on soft carbonate and mineral sand, 0.8 km W of Pigeon Point, Tobago I., R. Masino! (UF 496633); 16 spec., 12.6 x 4.7, 12.7 x 4.9, 9.5 x 3.7, 10.3 x 3.9 & 10.5 x 4.0 mm (MNRJ 34640), 10.8 x 4.0, 8.8 x 3.4, 9.9 x 3.9, 11.2 x 4.2, 10.1 x 4.1, 9.7 x 3.7, 9.5 x 3.7, 11.8 x 4.4 & 12.8 x 4.8 mm (MZSP 122056), 10.2 x 3.9 & 10.2 x 4.2 mm (author’s coll.), in 23 m, 2.4 km NNW of Crown Pt., Store Bay, Tobago I., R. Masino!; 13 [of 21] spec., 12.5 x 4.8, 11.4 x 4.4, 11.2 x 4.3, 11.6 x 4.4 & 11.5 x 4.4 mm (USNM 1291325), 10.8 x 4.1, 11.7 x 4.2, 11.4 x 4.4, 11.7 x 4.4, 10.4 x 4.0, 11.1 x 4.2, 9.7 x 4.0 & 10.0 x 3.9 mm (ANSP 464982), in 10–30 m on silty fine sand, Store Bay, Tobago I., N. Deynzer!; 4 [of 6] spec., 9.5 x 4.1, 7.2 x 3.2 mm (BMSM 14986), 12.0 x 4.5 mm (BMSM 14984) & 11.6 x 4.7 mm (BMSM 14985), in 15–24 m, on silty fine sand, Store Bay, Tobago I., P. Fallon! 8, 11 Nov 1999; 2 spec., 10.0 x 4.1 & 9.5 x 3.8 mm, in 15–18 m, Store Bay, Tobago I., G. Mackintosh! Mar 2002 (P. Stahlschmidt coll.).

Type locality. 2.4 km NNW of Crown Pt., Store Bay, Tobago I., Trinidad & Tobago in 23 m.

Other material examined. An additional 18 specimens were examined: 2 spec., 10.9 x 4.5 & 9.8 x 4.0 mm, in 7–11 m, off Buccoo Point, Tobago, C.W. Sheafer! May 1958 (UF 156118); 14 spec., 11.4 x 4.8, 11.7 x 4.5, 11.1 x 4.5 & 11.0 x 4.7 mm (USNM 1291326), 11.1 x 4.6 mm (ANSP 464971), 10.1 x 3.9, 11.5 x 4.7 & 10.1 x 4.2 mm (ANSP 464981), 10.0 x 4.2, 10.6 x 4.3, 10.2 x 4.1 & 12.0 x 4.6 mm (MZSP 122055), 10.8 x 4.4 & 10.5 x 4.2 mm (author’s coll.), in 9 m, Maracas Bay, Trinidad I., G. Mackintosh! 8 Dec 2003; 1 spec., 11.9 x 4.6 mm, in 90–100 m, Nieuwpoort, Curaçao, T. McCleery! May 2004 (P. Stahlschmidt coll.); 1 spec., 12.0 x 4.5 mm, in 10–12 m, off Malmok Beach, Aruba, Neth. Antilles, M. Coltro!, Sep 2004 (P. Stahlschmidt coll.).

Range and habitat. Trinidad & Tobago ( Tobago I.; Trinidad I.); Netherlands Antilles ( Curaçao; Aruba). Reported from on fine silty sands in a relatively sheltered bay in 9– 24 m.

Description. Shell small (to 12.8 mm), fusiform, glossy, translucent between ribs and spiral threads; whorls convex, about 9¾ total, the last approximately 57% of total length; sulcus present, about ¼-whorl height; principal sculptural element of ribs and spiral threads. Protoconch approximately 1¾–2¼ whorls, a clearly visible carina arising about ¼-turn from the tip beginning mid-whorl, but is sub-peripheral beginning on 2nd; the 2nd whorl is wider than first teleoconch whorl, the protoconch appearing somewhat bulbous. Axial sculpture of numerous narrow, opisthocline ribs, suture-to-suture; recurved in sulcus and extending to anterior fasciole on last, 14–15 on penultimate, 10–13 on last whorl to varix or to varix crest where they often appear; rib interspaces much wider than ribs. Varix broad, hump-like, approximately ⅓-turn from edge of outer lip. Spiral sculpture of flattened threads, interspaces less than thread width, or alternatively, wide grooves evenly spaced creating the appearance of flattened threads, closer and narrower in sulcus; threads override axials giving them a somewhat nodulose appearance. Sulcus convex, with 4–6 closely packed spiral threads, together appearing like a wide subsutural fold. Outer lip flattened from varix to edge of lip thus projecting out from the curvature of the shell in apical view; with up to 5 axial folds; lip edge forms a flat arc from anal sinus to the stromboid notch, and is inflected at anterior canal, bent inward posteriorly. Stromboid notch deep, edge flared. Anal sinus deep, mid-way on whorl shoulder, U-shaped, entrance slightly constricted by callus on parietal wall; outward flare of sinus edge gives the appearance of being spout-like. Inner lip erect anteriorly where a chink forms between it and fasciole on older specimens, recumbent and wider on parietal wall, and formed into a lobe posteriorly; successive growth increments visible on edge of lip. Anterior canal open, moderately long, turned to the right when viewed ventrally; canal end upturned, and notched asymmetrically across its width. Anterior fasciole slightly swollen with spiral threads on surface forming a marginal ridge along its adapical edge. Color pink with light orange-yellow maculation between ribs in the sulcus; flesh-colored with light brown between ribs in the sulcus; brownish-pink with a whitish mid-whorl band and rib crests, sulcus and above suture darker, apex pink and a brown stain on the varix, or lavender pink with light brown between ribs in the sulcus and a brown-stained varix.

Remarks. Taxonomy. Calliclava tobagoensis has all of the characteristics of the genus: numerous ribs that extend from suture-to-suture with a distinctly delineated sulcus, conspicuous spiral grooves (threads) across intercostal spaces, and a protoconch with both whorls carinate. Variability. The average total length of 54 specimens is 10.79 mm (7.2–12.8 mm) and their average W/ L ratio is 0.392. Specimens vary in color by locality (of examined specimens); those from Store Bay, Tobago I. are brownish-pink, have a whitish mid-whorl band and rib crests, darker sulcus, pink apex; and brown-stained varix. Those from Maracas Bay, Trinidad I. are lavender pink and have light brown between ribs in the sulcus, and a brown stained varix. Specimens from the latter locality are stouter than those from the former. The Trinidadian 14 have an average W/ L ratio of 0.406, compared to the slimmer W/ L ratio of 0.386 of the 39 Tobagoan specimens. These differences in color and form are not believed to merit their separation at species level, but further study is merited. Identification. Calliclava tobagoensis may be confused with Agladrillia rhodochroa (Dautzenberg, 1900) , which is similar in size, color, and sculpture. The distinctions are that A. rhodochroa has a smooth almost translucent last whorl dorsum, without axials, the varix precedes the edge of the outer lip by about ½-turn, and has a “pinched” anterior canal, unlike the more even tapered one of C. tobagoensis . Calliclava tobagoensis is also similar to C. fasciata , new species but differs in being smaller, differently colored, and has some minor differences in shell morphology. The average total length of C. tobagoensis is 10.8 mm versus 16.70 mm for the larger C. fasciata . Calliclava tobagoensis has a fairly uniformlycolored shell with maculations in the intercostal spaces on whorl shoulders; C. fasciata has a white shell with a wide, mid-whorl spiral color band. From Calliclava vigorata , new species it differs in being smaller (average total length of 10.80 mm versus 14.08 mm), in possessing a narrower last whorl and an anterior canal that is straighter, not bent as much to the right as in C. vigorata , when viewed ventrally.

Etymology. The Tobago Calliclava , named for the island in which its type locality is located.

Figures

PLATE 18. Calliclava tobagoensis, new species. Upper Panel. Figs. 1, 3: holotype, Store Bay, Tobago I., Trinidad & Tobago (USNM 1291324). Fig. 1: ventral, lateral & dorsal views; Fig. 3: apical view, V = varix, L = edge of outer lip. Fig. 2: paratype, Store Bay, Tobago I. (USNM 1291325), enlarged view of protoconch only (not to scale). Lower Panel. Figs. 4 – 6: paratypes, Store Bay, Tobago I. Figs. 4, 6: MZSP 122056; Fig. 5: MNRJ 34640; Figs. 7 – 11: paratypes, W of Pigeon Point, Store Bay, Tobago I. Figs. 7 – 10: USNM 1291325; Fig. 11: ANSP 464982; Figs. 12 – 19, Maracas Bay, Trinidad I. Fig. 12: MZSP 122055; Figs. 13 – 14: USNM 1291326; Figs. 15 – 16: author’s coll.; Figs. 17 – 18: ANSP 464981; Fig. 19: MZSP 122055.