Neopleurotomoides aembe, Figueira, Raquel Medeiros Andrade & Absalão, Ricardo Silva, 2012

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 : 8-9

Neopleurotomoides aembe n. sp.

( Figs. 5–8 )

Type material: Holotype MNRJ 30285 [1] OP II # 48 (22° 11' 16"S, 39° 43' 44"W), 3.18 mm, 1968 m. Paratype MNRJ 30286 [1] OP II # 48 (22° 11' 16"S, 39° 43' 44"W), 1.68 mm, 1968 m. Paratype IBUFRJ 18417 [2] OP I # 63 (21° 52' 44"S, 39° 40' 45"W), 1.98 mm and 3.92 mm, 1950m. Paratype IBUFRJ 18437 [1] OP II # 87 (22° 33' 08"S, 39° 54' 21"W), 3.14 mm, 1934m. Paratype MZSP 108228 [3] OP I # 58 (21° 57' 26"S, 39° 40' 33"W), 1.92 mm, 2.34 mm and 3.64 mm, 1950 m. Paratype MCZ 374805 [1] OP II # 63 (21° 52' 43"S, 39° 40' 41"W), 1.84 mm, 1941 m. Paratype MCZ 374806 [1] OP II # 59 (21° 52' 59"S, 39° 55' 32"W), 4.04 mm, 751 m. Paratype MNHN [2] OP II # 84 (22° 26' 28"S, 39° 58' 53"W), 1.94 mm and 3.14 mm, 1046m. Paratype MNHN [2] OP I # 53 (22° 04' 46"S, 39° 43' 02"W), 3.4 mm and 3.96 mm, 1950m. Paratype USNM 1187762 [1] OP II # 52 (22° 04' 45"S, 39° 46' 31"W), 1.66 mm, 1643m. Paratype USNM 1187763 [2] OP I # 53 (22° 04' 46"S, 39° 43' 02"W), 3.6 mm and 3.94 mm, 1950m. Type locality: 22° 11' 16"S, 39° 43' 44"W, Campos Basin, Southeast Brazil, Southwestern Atlantic, 1968 m.

Material examined: Type material and 17171 [11] OP I # 44; 18408 [13] OP I # 45; 18409 [1] OP I # 46; 18410 [1] OP I # 47; 18411 [5] OP I # 48; 18412 [1] OP I # 50; 18413 [4] OP I # 53; 18414 [3] OP I # 58; 17069 [2] OP I # 59; 18415 [4] OP I # 60; 18416 [5] OP I # 61; 18417 [2] OP I # 63; 18418 [1] OP I # 67; 15350 [4] OP I # 74; 18419 [22] OP I # 75; 18420 [2] OP I # 80; 18421 [1] OP I # 83; 18422 [1] OP I # 86; 18423 [35] OP II # 45; 18425 [2] OP II # 50; 18426 [1] OP II # 52; 18427 [2] OP II # 53; 18428 [1] OP II # 57; 18429 [2] OP II # 59; 18430 [1] OP II # 62; 18431 [1] OP II # 63; 15546 [1] OP II # 69; 17274 [3] OP II # 74; 18432 [20] OP II # 75; 18433 [2] OP II # 77; 18434 [10] OP II # 80; 18435 [2] OP # 83; 18436 [4] OP II # 84; 18437 [1] OP II # 87; 18438 [3] B # 32.

Description: Shell small, white, up to 3.18 mm long. Protoconch with four whorls, light yellow. Protoconch 1 slightly darker, with rows of tiny crosses. Protoconch 2 with a rounded middle keel, a thin suprasutural spiral cord and several axial riblets. Riblets extend from the lower edge of the whorls until midway between the keel and the upper edge of the whorls, and from above they extend down from the suture to the same midway area, almost touching the riblets extending upward. Clear-cut protoconch to teleoconch transition. Teleoconch whorls with convex profile, with curved axial lines on an oblique subsutural zone. Below this zone, about five spiral cords, evenly spaced except for the upper two which are very close to each other, crossed by 14–16 axial ribs (on the 2nd whorl) with the formation of acute nodules at the intersections. Entire surface of the shell covered by tiny granules. Suture shallow. Sculpture of the body whorl continues on the upper half of the base, but on the lower half the axial ribs disappear and 5–9 thin spiral cords remain. Anal sinus broad and moderately deep. Anterior siphonal canal wide and short. Aperture elliptical.

Etymology: Aembé is a word in Tupy, a major language of Brazilian indigenous peoples, and means “rough to the touch”, referring to the tiny granules that cover the shell surface.

Geographic distribution: Only known from Campos Basin, off Rio de Janeiro, 743–1970 m.

Discussion: Neopleurotomoides aembe n. sp. is similar to Neopleurotomoides rufoapicata , but besides the extensive geographical distance between the two species ( N. rufoapicata is known from the Indo-Pacific Ocean, around Indonesia), Neopleurotomoides aembe n. sp. has a broader subsutural zone, the whorls are less convex, and there are small acute nodules where the axial ribs cross the spiral cords.

The only species of Neopleurotomoides reported from the Atlantic Ocean are Neopleurotomoides callembryon ( Dautzenberg & Fisher, 1896) and Neopleurotomoides distincta Bouchet & Warén, 1980 , both from the North Atlantic. Neopleurotomoides aembe n. sp. can be distinguished from N. callembryon ( Bouchet & Warén, 1980: 44, figs. 100–101) by its less inflated shell profile, broader subsutural zone, weaker spiral cordlets, weaker nodules and narrower aperture. In addition, the protoconch of N. callembryon has axial riblets only below the middle keel, while in Neopleurotomoides aembe n. sp. they are present below and above the middle keel. Neopleurotomoides aembe n. sp. shares with N. distincta the general shell profile, including the subsutural zone (and its ornamentation), protoconch ornamentation and aperture shape, but it can be distinguished by the fewer and weaker spiral cordlets and by the presence of acute nodules on the intersections of the spiral cordlets with axial ribs.

Figures

FIGURES 1 – 11. 1, 2 — Aliceia aenigmatica Dautzenberg & Fischer, 1897, IBUFRJ 18442; 1 — 4.02 mm, whole shell; 2 — protoconch; 3, 4 — Famelica mirmidina Dautzenberg & Fischer, 1896; 1 — IBUFRJ 18465, 4.94 mm, whole shell; 2 — IBUFRJ 18452, protoconch; 5, 6, 7 — Neopleurotomoides aembe n. sp.; 5, 8 — Holotype MNRJ 30285; 5 — 3.18 mm, whole shell; 8 — detail of shell surface; 6 — Paratype MZSP 108228, 3.64 mm, whole shell; 7 — Paratype MNRJ 30286, protoconch; 9, 10, 11 — Eubela limacina (Dall, 1881); 9 — Syntype MCZ 7111; 10 — IBUFRJ 13847, 7.32 mm, whole shell; 11 — IBUFRJ 15348, protoconch. Scale bars: 1, 3, 5 and 6 = 500 μm; 2, 4, 7 and 11 = 300 μm; 8 = 50 μm; 9 and 10 = 1 mm.