Turbonilla alvheimi, Lygre, Frøydis & Schander, Christoffer, 2010

Lygre, Frøydis & Schander, Christoffer, 2010, Six new species of pyramidellids (Mollusca, Gastropoda, Pyramidelloidea) from West Africa, introducing the new genus Kongsrudia, Zootaxa 2657, pp. 1-17 : 13

Turbonilla alvheimi new species

( Fig 8 A–E )

Type material: Holotype, Bergen Museum ZMBN 86663. One paratype, type locality, Bergen Museum ZMBN 86664.

Type locality: Gabon station G3, 00º 05’N, 09º 02’E, 61 m.

Material examined: Type material.

Etymology: The species is named in honor of Oddgeir Alvheim who is a senior technician of the Nansen program. Alvheim have had a long career as a senior research technician at the Institute of Marine Research. He has participated in cruises connected with the Nansen program since the beginning of the 1980’s and was the cruise leader on one of the GCLME surveys that provided material for this study. He has devoted his life to field work off the coast of Africa and is among those people with the best general knowledge of the marine fauna in Africa.

Description: Shell tall, solid, conical, milky white and shiny with pointed apex. A very diffuse colored broad band is seen in middle/lower half of whorls. Protoconch of type A-I, small and semi-submerged. Whorl almost straight, slightly turreted. Suture distinct, broad and channeled. Axial ribs elevated, strong almost straight, shouldered and orthocline or slightly opisthocline. Ribs and interspaces about equally broad. Ribs disappear at the periphery of the ultimate whorl or continue as diffuse and thin extensions on base. Spiral sculpture consisting of rectangular grooves, not equal or equidistant. Bands between grooves not equal, for the most part broader than grooves. Spiral grooves present on base. Aperture rhomboid. Inner lip slightly folded. No columellar tooth. No umbilicus.

Distribution: Gabon 61 m.

Remarks: This species shows a certain resemblance to Turbonilla abrardi Fischer-Piette & Nicklés, 1946 , but the protoconch is less submerged and the suture is broader and deeper in Turbonilla alvheimi . The whorls are more convex and the axial ribs not as strong and not shouldered in Turbonilla abrardi . Turbonilla jeffreysi (Thompson, 1850) is more turreted and has a less pronounced suture, the axial ribs are narrower, not as tightly spaced and less strong. The grooves are also more narrow in T. jeffreysi . Turbonilla rufescens ( Forbes, 1846) have slightly more convex whorls. The suture and sculpture differs in the same manner as T. jeffreysi .

Figures

FIGURE 8 A – E. Turbonilla alvheimi n. sp. A: Holotype teleoconch, station G 3, Gabon, 00 º 05 ’ N 09 º 02 ’ E; B: Paratype teleoconch, station G 3, Gabon, 00 º 05 ’ N 09 º 02 ’ E; C: Holotype protoconch; D: Holotype details of the sculpture and base; E: Holotype details of the suture.