Lissodrillia fasciata, 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 : 243-244

Lissodrillia fasciata , new species

( Plate 123 )

Type material. Holotype 7.2 x 2.6 mm, J. Coltro!, Aug 2005 (MZSP 122069); no paratypes. Type locality. 120 mi [193 km] off Fortaleza, Canopus Bank, Ceara State, Brazil, in 260 m. Range and habitat. Known only from the holotype.

Description. Shell very small (7.2 mm), fusiform (W/L = 0.361), glossy smooth, translucent; of about 7½ strongly convex and moderately elongate whorls, peripheries about mid-whorl, the last about 56% of total shell length; suture impressed. Sculptural elements only of ribs; aperture narrow, with a short, wide anterior canal and large spout-like anal sinus. Protoconch of 2 smooth glossy whorls, the beginning of the first slightly imbedded in the last whorl such that the spire tip appears blunt. Axial sculpture of low, opisthocline ribs, about as wide as their interspaces, obsolete on shoulder near suture and fade just below whorl periphery, before suture of succeeding whorl. Rib crests are round. The base of the last whorl is smooth, without ribs. Growth striae microscopic. Varix obscure, the last rib is about ⅓-turn from edge of outer lip. Spiral sculpture absent. Sulcus smooth, without sculpture, flat, not concave. Growth striae, curved reflecting past positions of the anal sinus. Outer lip thin, without axial folds, smooth, edge inrolled from anal sinus to beginning of anterior canal; stromboid notch absent. Anal sinus a deep notch on whorl shoulder near suture, edge flared and directed laterally, appearing spout-like. Inner lip thin, margined, recumbent; extending over apex of aperture with a weak callus at anal sinus. Anterior canal short but well defined, open, unnotched. Color translucent white with a light golden brown band mid-whorl, darkened at rib sides.

Remarks. Taxonomy. Lissodrillia fasciata has the characteristics of the genus: a small glossy shell with a short anterior canal that lacks spiral sculpture. Unlike most of its congeners, the sulcus is devoid of ribs, which are also quite short for the genus, not extending much past the periphery of the whorl Splendrillia -like. Unlike in Splendrillia though, this species lacks spiral sculpture and posses a different anal sinus. Identification. The species is differentiated from its congeners by its tall narrow spire (overall W/L = 0.361, which is on the narrow end of the range of its congeners), light golden brown mid-whorl band, and flat sulcus that lacks sculpture. It is most similar to L. verrillii (Dall, 1881) , which also has convex whorls and a bare sulcus, but that species has more convex whorls, is smaller, and lacks the color band. The strongly convex whorls of L. fasciata are reminiscent of L. turgida , new species but that species is smaller (4.72 mm average total length), lacks the flat sulcus, and has more convex ribs. Lissodrillia fasciata is somewhat similar in form to L. vitrea , new species but is larger, has proportionally shorter ribs, and light golden brown mid-whorl band, which is absent in L. vitrea . The single wellpreserved type specimen has distinctly different morphological characteristics from its congeners as described above. As the sole representative of the genus in the southeastern Caribbean it was felt that it merited description as new.

Etymology. Lissodrillia fasciata , the Banded Lissodrillia from the Latin adjective fasciata meaning possessing a band, a reference to its mid-whorl color band.

Figures

PLATE 123. Lissodrillia fasciata, new species. Figs. 1 – 3: holotype, off Fortaleza, Ceara State, Brazil (MZSP 122069). Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged view of protoconch (not to scale); Fig. 3: apical view, L = edge of outer lip.