Splendrillia vinki (Jong & Coomans, 1988) Jong & Coomans, 1988

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 : 312

Splendrillia vinki (Jong & Coomans, 1988) , new combination

( Plate 161 )

Inodrillia vinki Jong & Coomans, 1988: 112 –113, pl. 43, fig. 597: Williams (2005; 2006; 2009: species 3255, three left-most photos only).

Type material. Holotype 12 x 4.0 mm (ZMA 3.87.099) according to Jong & Coomans (1988: 112–113). The holotype is missing (M. Faber, research notes); a photograph of the holotype, taken by these authors and provided by Faber, was used as a representation of the type (Pl. 161, Fig. 1 ).

Type locality. Malmok, Aruba, Netherlands Antilles.

Material examined. An additional 18 specimens were examined: 2 spec., 8.9 x 3.5 & 8.5 x 3.1 mm, on coralline sand at 1.8 m, Aruba (USNM 1291365); 1 spec., 9.6 x 3.5 mm, on coralline sand at 1.8 m, Aruba (ANSP 464959); 1 spec., 8.7 x 3.5 mm, Aruba, T. McCleery!, Dec 1998 (ANSP 464960); 2 spec., 12.1 x 4.3 & 10.7 x 3.9 mm, Malmok, M. Beerman!, 24 Aug 1967 (UF 496647); 9 spec., 12.3 x 4.3 mm (UF 470345), 13.1 x 4.5, 14.6 x 4.8, 12.2 x 4.8, 9.9 x 3.6, 11.1 x 4.2, 10.2 x 4.4, 11.4 x 4.4 & 10.5 x 3.7 mm (author’s coll.), all beach collected, Malmok and Punta Braboe, A.N. de Mann! Mar–Jun 1964 and Aug 1966; 2 spec., 8.2 x 3.0 & 8.9 x 3.2 mm, in 10– 15 m, Malmok, Aruba, T. McCleery, Jan 2008 (BMSM 14998); 1 spec., 10.3 x 3.7 mm, in 100–120 m, off Cape Arraial, Rio de Janeiro, Brazil, P. Gonçalves! Apr, 2011 (MZSP 122076).

Range and habitat. Aruba; Brazil (off Cape Arraial, Rio de Janeiro). Reported from 2–15 m from Aruba; 100–120 m from off Rio de Janeiro, Brazil.

Description. The original is based on a single specimen with an immature lip so mature specimens, non-types, were examined to more fully characterize the species. Shell small (to 14.6 mm), narrowly fusiform with a truncated anterior, glossy, with up to 9 slightly convex whorls, the last whorl 58% of the total shell length. Protoconch of 2 smooth whorls. Axial sculpture of slightly oblique ribs confined mostly to the periphery of the whorls, almost knob-like, terminating at the sulcus, the first teleoconch whorl has weak riblets at first and altogether more ribs than the second, 9–12 are on the penultimate whorl and 5–8 on the last whorl to the varix. Space between the axials greater than their width. Growth striae present; most pronounced on the body whorl from the varix to the edge of the outer lip. Varix weak, hump-like about ¼-turn from edge of outer lip. Spiral sculpture mostly absent; approximately 2 faint spiral ridges visible on the lower portion of the shell base, and 4 ridges on the anterior fasciole. Sulcus flat, without spiral or axial sculpture. Outer lip thin, outer edge runs in a low arc from the anal sinus to the anterior canal without any inflection and projecting out from the circumference of the shell; flattened behind from the varix to its edge; lip edge slightly inflected. Stromboid notch present but very shallow, close to the tip of the canal. Anal sinus moderately deep, adjoins suture at its apex behind parietal callus. Inner lip margined anteriorly, thin or absent on the parietal wall, ending in a callus at the suture. Anterior canal short; open, barely demarcated from the anterior portion of the aperture; sulcus not swollen; tip of canal slightly notched. Color light to dark caramel; leading edge of varix and broad indistinctly margined central band between ribs darker, shell apex, anterior fasciole, aperture and outer lip lighter to white, as are rib crests. All very light-colored specimens are beach-collected and probably faded.

Remarks. Taxonomy. Splendrillia vinki has all the characteristics of Splendrillia . The genus Inodrillia Bartsch, 1934 ( Crassispirinae , Tippett, 1995: 135), its original placement, is characterized by the presence of riblets on the second protoconch whorl. The growth striae that appear at the end of the smooth whorls of the protoconch of S. vinki or the numerous ribs of the first teleoconch whorl may have been interpreted as being protoconch riblets, but Inodrillia also has strong axial ribs and spiral threads on the teleoconch, and a strong varix a little behind the outer lip. As with crassispirines in general, Inodrillia has a thick parietal callus that extends up to the suture forming a shelf that partially occludes the opening of the anal sinus in mature specimens. These features are not found in S. vinki . Variability. The average total length of 17 specimens is 10.95 mm (8.5–14.6 mm) and their average W/ L ratio is 0.368. Color varies from very light to dark caramel, with a white apex, anterior, and rib crests. The specimen from off Cape Arraial, Rio de Janeiro represents a significant geographic jump from all other known occurrences (Pl. 161, Fig. 10). It also varies from the type in possessing somewhat stronger ribs, a larger protoconch, and darker caramel color. These differences are not believed to rise to the level of species, however. Identification. Splendrillia vinki resembles S. interpunctata (E.A. Smith, 1882) , but is smaller and differs in color. It differs from S. coccinata (Reeve, 1845) principally in the number and form of the axials, which are more angular, longer and more numerous in S. coccinata , and also in shell color. Splendrillia vinki also resembles Lissodrillia cabofrioensis , new species, which was compared under that species, and Cerodrillia brasiliensis , new species, but that species has axial ribs extending to the suture, and an entirely different anal sinus and varix structure.

Figures

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 161. Splendrillia vinki (Jong & Coomans, 1988). Upper left panel. Fig. 1: holotype, Malmok, Aruba, Netherlands Antilles (ZMA 3.87.099): ventral & dorsal views. Photo courtesy of Marien Faber. Fig. 2: specimen from Malmok, Aruba, Netherlands Antilles (UF 496647): ventral view. Fig. 3: enlarged view if protoconch of specimen in Fig. 13 (not to scale); Fig. 4: apical view of specimen in Fig. 15, V = varix, L = edge of outer lip. Lower panel. Fig. 5: Aruba, Netherlands Antilles, ventral, lateral & dorsal views of a fresh specimen (ANSP 464959); Fig. 6: same specimen as in Fig. 2; Fig. 7: Punta Braboe, Aruba, Netherlands Antilles (UF 470345); Figs. 8 – 9: Punta Braboe, Aruba, Netherlands Antilles (author’s coll.); Fig. 10: Cape Arraial, Rio de Janeiro, Brazil (MZSP 122076); Figs. 11 – 13: Aruba, Netherlands Antilles. Figs. 11, 13: USNM 1291365; Fig. 12: ANSP 464960. Figs. 14 – 15: Malmok, Aruba, Netherlands Antilles (BMSM 14998).