Pleurotomella bureaui

Figueira, Raquel Medeiros Andrade & Absalão, Ricardo Silva, 2012, Deep-water Raphitomidae (Mollusca, Gastropoda, Conoidea) from the Campos Basin, southeast Brazil, Zootaxa 3527, pp. 1-27 : 24

Pleurotomella bureaui ( Dautzenberg & Fischer, 1897a)

( Figs. 49–50 )

Pleurotoma bureaui Dautzenberg & Fischer, 1897a: 37 : Dautzenberg & Fischer (1897b: 149, pl. 3, fig. 1); Dautzenberg (1927: 45, pl. 2, fig. 20);

Pleurotomella bureaui (Dautzenberg & Fischer, 1897) : Bouchet & Warén (1980: 36, figs. 88, 218).

Type material: In Museé Océanographique de Monaco.

Type locality: Azores, Hirondelle (1888), sta. 39 (39º 26’ 30”N, 33º 23’W), 1557 m; sta. 47 (39º 18’ 05”N, 33º 32’ 15”W), 1372 m; Princesse Alice (1896), sta. 74 (39º 21’ 20”N, 33º 26’W), 1360 m; sta. 90 (39º 11’N, 32º 44’ 30”W), 1600 m.

Material examined: 15358 [3] OP I # 74; 19199 [1] OP I # 86; 19200 [1] OP II # 61; 19201 [1] OP II # 84.

Description: Shell conical, white, up to 8.12 mm long. Protoconch with about 3.5 whorls. Protoconch 1 with rows of tiny crosses. Protoconch 2 with diagonal cancellation on the lower 2/3 of the whorls and axial riblets crossed by fine spiral threads on the upper third. Clear-cut proto-teleoconch boundary. Teleoconch with a subsutural concave area sculptured with numerous axial riblets and a spiral cordlet. Below this area, about 14 strong axial ribs (on the third whorl) crossed by two to three spiral cords, with the formation of acute nodules in the intersections. Shell surface granulose. Suture shallow. Base elongated, ornamented with about 12 spiral cords. Inner lip reflected over parietal wall. Outer lip thin. Anterior siphonal canal relatively long and narrow. Aperture elliptical.

Geographic distribution: Northeast Atlantic: Azores ( Dautzenberg & Fischer, 1897a; Dautzenberg & Fischer, 1897b; Dautzenberg, 1927); Azores and Morocco ( Bouchet & Warén, 1980). Southwest Atlantic: Campos Basin, Rio de Janeiro (this paper). Bathymetry: 750–1650 m (this paper).

Discussion: Our material shows a very good fit with the type illustrated by Dautzenberg & Fischer (1897b: pl. 3, fig. 1) and the specimen illustrated by Bouchet & Warén (1980: 37, fig. 88). However, our material does not have the secondary spiral cordlets observed on the body whorl of the type. We attribute this discrepancy to the difference in size, since our specimens are younger. This species can be recognized by the presence of a thin subsutural cordlet overlain by numerous strong axial riblets, and by the somewhat spiny appearance.

Pleurotomella bureaui is reported for the first time in South Atlantic waters. It was previously known to occur in Azores and Morocco. Its bathymetric range is also increased. It was previously reported in depths between 1360–1600 m ( Dautzenberg & Fischer, 1897a) and it has now been found at 750–1650 m.

Figures

FIGURES 47 – 55. 47, 48 — Pleurotomella cf. anceyi Dautzenberg & Fischer, 1897, IBUFRJ 18984; 47 — 6.90 mm, whole shell; 48 — protoconch. Figures 49, 50 — Pleurotomella bureaui Dautzenberg & Fischer, 1897, IBUFRJ 19201; 49 — 4.30 mm, whole shell; 50 — protoconch. Figures 51, 52, 53, 54, 55 — Pleurotomella ybessa n. sp.; 51 — Holotype MNRJ 30288; 12.26 mm, whole shell; 52, 54, 55 — Paratype IBUFRJ 19191, 52 — 6.06 mm, whole shell; 54 — detail of shell surface; 55 — protoconch; 53 — Paratype MCZ 374809; 5.88 mm, whole shell. Scale bars: 47, 49, 52 and 53 = 750 μm; 48, 50 and 55 = 250 μm; 51 = 2 mm; 54 = 25 μm.