Lissodrillia cabofrioensis, 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 : 239-241

Lissodrillia cabofrioensis , new species

( Plate 121 )

Splendrillia espyra auct. non (Woodring, 1928), a misidentification by Rios (1985: 140, pl. 47, fig. 643), is likely this species. Syntomodrillia espyra auct. non Woodring, 1928: Rios (1994: 163, pl. 54, fig. 735); Rios (2009: 314, sp. 799), is likely this species.

Type material. Holotype 7.4 x 2.9 mm (MZSP 122068); 6 paratypes, all from the type locality: 7.5 x 2.7 & 7.2 x 2.6 mm (ANSP 464992); 6.9 x 2.7 & 7.3 x 2.6 mm (UF 496644); and 6.5 x 2.5 & 6.4 x 2.6 mm (MNRJ 34638).

Type locality. Off Cabo Frio, Rio de Janeiro state, Brazil, in 100 m depth.

Range and habitat. Confirmed specimens are only from the type locality. Rios’ report of S. espyra Woodring, 1928 from off São Tomé, Rio de Janeiro, with an overall range from Espirito Santo to Rio de Janeiro states, Brazil, would apply here if they prove to be the same. Reported from 100 m depth. Rios’ report (for Syntomodrillia espyra, Woodring, 1928 ) indicates a possible depth range of 45– 100 m.

Description. Shell very small (to 7.5 mm), glossy, narrowly fusiform, of 6½ slightly convex whorls with appressed sutures and low, short axial ribs. Protoconch of approximately 2 smooth, large (relative to shell size) whorls, the first mostly submerged so that the protoconch appears blunt; beginning of growth striae taken as onset of teleoconch. Axial sculpture of low opisthocline axial ribs very much reduced in the sulcus, fade just below the whorl’s periphery such that they appear like nodules; width of the ribs less than their interspaces, 10–13 on the penultimate and 10–12 on the body whorl. Axials on body whorl sometimes obscured by strong growth striae. Spiral sculpture absent. Sulcus with reduced to obsolete ribs, but with arcuate growth striae reflecting the outline of the anal sinus. Varix obsolete. Outer lip thin, with a very shallow stromboid notch. Anal sinus a deep notch; outer edge divergent, such that it and the edge of the outer lip trace a reverse “S” when viewed laterally. Inner lip is very thin to absent on the parietal wall, thicker on the anterior canal, and terminates in a slight swelling near the posterior sinus. Columella curved slightly to the left. Anterior canal short, wide, unnotched, with heavy growth striae on anterior fasciole. Color caramel, a lighter, narrow band below the whorl periphery visible only on the body whorl; rib crests paler.

Remarks. Taxonomy. Lissodrillia cabofrioensis is a small, glossy species that lacks spiral ornamentation, and has anal sinus that is a deep notch with a divergent outer edge characteristic of Lissodrillia . Its short, low ribs that are reduced in the sulcus are uncharacteristic. Variability. The average length of seven specimens is 7.03 mm (6.4– 7.5 mm) and average W/L is 0.379. Little variability is exhibited by the specimens examined. Identification. Lissodrillia cabofrioensis is similar to Bellaspira rosea , new species of the same color and size of a form of that species and taken from the same general area. It can be distinguished from that species by the absence of spiral grooves or threads on the anterior fasciole, its deeper anal sinus, lack of spiral incised lines, and its opisthocline ribs (straight in B. rosea ). It is also similar in size and color to a second species in a different genus, Cerodrillia brasiliensis , new species, but that species has axial ribs extending to the suture, a proportionally large cup-handlelike varix, and spiral ridges on its base and anterior fasciole ( Plate 23 ). Splendrillia vinki (Jong & Coomans, 1988) is similar, but larger and has more prominent ribs.

Etymology. The Cabo Frio Lissodrillia . Named after the type locality.

Figures

PLATE 23. Cerodrillia brasiliensis, new species. Upper panel. Figs. 1 – 3: holotype, off Rio de Janeiro, Brazil (MZSP 122058). 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. Lower panel. Figs. 4 – 10, 18, 23: paratypes from off Santos São Paulo, Brazil. Figs. 4 – 6: ANSP 464968; Figs. 7 – 9: UF 496634; Figs. 10, 18, 23: MNRJ 34633. Figs. 11 – 17, 19 – 22: paratypes from off Cabo Frio, Rio de Janeiro, Brazil: Fig. 11: MZSP 122059; Figs. 12 – 15, 19: BMSM 14987; Figs. 16, 21: author’s coll.; Figs. 17, 20: MZSP 122059; Fig. 22: MNRJ 34633.

PLATE 121. Lissodrillia cabofrioensis, new species. Upper panel. Figs. 1 – 3: holotype, off Cabo Frio, Rio de Janeiro State, Brazil (MZSP 122068). Fig. 1: ventral, lateral, & dorsal views; Figs. 2 – 3: different views of the protoconch (not to scale). Lower panel. Figs. 4 – 9: paratypes, from off Cabo Frio, Rio de Janeiro State, Brazil. Figs 4 – 5: ANSP 464992; Figs. 6 – 7: UF 496644; Figs. 8 – 9: MNRJ 34638.