Clathrodrillia rubrofasciata, 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 : 105-107

Clathrodrillia rubrofasciata , new species

( Plate 47 )

Type material. Holotype 31.0 x 11.3 mm, A. Bodart! (MZSP 122061); 2 paratypes: 1 spec., 29.2 x 10.4 mm, in 21–27 m depth, off Alcobaça, Bahia State, Brazil, A. Bodart! (MNRJ 34634); 1 spec. 30.1 x 11.1 mm, in 37 m, off Campos, Rio de Janeiro State, Brazil, A. Bodart! (P. Stahlschmidt coll.).

Type locality. Off Campos, Rio de Janeiro State, Brazil, at 35 m.

Range and habitat. Brazil (Bahia and Rio de Janeiro States). Reported from 21– 35 m.

Description. Shell medium (to 31.0 mm in total length), fusiform, truncated anteriorly with a constricted base at the level of the stromboid notch, tall spire and somewhat acuminate tip, short anterior canal, whorls turreted with concave sulcus, impressed sutures, round shoulders and somewhat flattened sides. Whorls total 12, last whorl 51% of total shell length; aperture narrowly oval; shell sculpture of axial ribs cut by spiral grooves. Protoconch of approximately 1¾–2 smooth whorls, tip partially immersed in second whorl. Beginning of teleoconch is taken at the appearance of axial ribs. Axial sculpture of straight axial ribs that run from suture-to-suture on spire whorls, recurved on shoulder of later whorls, evanesce below periphery of last whorl; 10–11 on penultimate and 5–7 on last whorl to varix; ribs progressively reduced in sulcus from first teleoconch to last whorl, such that only narrow crescent-shaped ridges occur on last 2–3 whorls that reflect past positions of anal sinus, some of which are raised and nodule-like. Rib crests round, becoming ridged on shoulder and in sulcus; intercostal space about as wide as the width of ribs. Irregular microscopic growth striae present on shell surface. Varix broad, hump-like, approximately ⅓-turn from edge of outer lip; 2–3 low axial folds present on surface of varix. Spiral sculpture of regularly spaced spiral grooves, 5–7 on penultimate and 12–15 on shell base below suture line to anterior fasciole; grooves override axial ribs. Anterior fasciole without distinct cords; crescent shaped striae from advancing growth present, sulcus with a few very faint spiral grooves. Sulcus margin demarcated by rapid drop in rib height and width; concave at its base (abapical side) and convex along the suture; ribs and growth striae crescent-shaped on later whorls, straighter on early teleoconch whorls. Faint spiral grooves in sulcus of early whorls mostly obscured by ribs and growth striae on later ones. Outer lip flattened, with 5 low axial folds; edge of lip traces a flattened arc along its length, smooth, not scalloped but rather lightly ruffled by the spiral groove ends; stromboid notch distinct but shallow and broad. Anal sinus deeply notched, round, parietal lobe forming one side; inner edge of sinus flared outward. Inner lip moderately wide, emarginated and with visible layers of deposition along it edge, erect anteriorly along columella, recumbent and widest on parietal wall, developed into a heavy lobe posteriorly. Anterior canal short but distinctly formed, open, twisted to the right at its tip when viewed ventrally, notched; fasciole not swollen, with 4–5 indistinct spiral grooves forming cords of varying widths; growth striae parallel to its edge. Color dirty white with a light-to-dark-brown mid-whorl spiral band and a fainter, narrower one below it confined to the intercostal spaces; with reddish-brown color between the ribs extending either side of the central band and on varix.

Remarks. Taxonomy. Clathrodrillia rubrofasciata has the morphological characteristics of Clathrodrillia : shell with a tall spire, with a concave sulcus, strong ribs cut by spiral grooves, broad hump-like varix about ⅓-turn from the edge of the outer lip, and a protoconch of about two smooth round whorls. Variability. The three examined specimens have an average total length of 30.1 mm (29.2–31.0) and an average W/ L ratio of 0.363. Identification. Clathrodrillia rubrofasciata is unique in its color pattern but somewhat similar in size and color to C. dautzenbergi (Tippett, 1995) and in form to Neodrillia princeps , new species. From C. dautzenbergi it differs in having fewer ribs (11 versus 18–22 on the penultimate whorl) and in its color, which is reddish, not light pink. From Neodrillia princeps , new species, which is similarly colored, it differs in possessing fewer ribs (10–11 versus 15–17 on the penultimate whorl), and in lacking the fine spiral sculpture typical of that genus (fewer spiral grooves versus numerous raised threads). In coloration, C. rubrofasciata is similar to Fenimorea kathyae Tippett, 1995 but differs in having deep spiral grooves that cut the ribs.

Etymology. The Red-banded Clathrodrillia , from the Latin adjectives rubro -, combining form of rubra, meaning red, and fasciatus, meaning banded. Named for its reddish-brown band, which is unique among its congeners.

Figures

PLATE 47. Clathrodrillia rubrofasciata, new species. Figs. 1 – 3: holotype, off Rio de Janeiro State, Brazil (MZSP 122061). 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. Figs. 4 – 5: paratypes. Fig. 4: off Alcobaça, Bahia State, Brazil (MNRJ 34634); Fig. 5: off Campos, Rio de Janeiro State, Brazil (P. Stahlschmidt coll.).