Terebralia marki sp. nov.

(Figure 4 (cc))

Diagnosis

Spiral ribs strongly opisthocline; six primary spiral cords weakly crossing axial ribs; no peripheral cord exposed near anterior suture.

Description

Shell fragment small, length less than 10 mm, thick. Elongate, pleural angle about 15°. Protoconch partly preserved but windblasted; probably multispiral, conical. Evidence of five whorls preserved; flat-sided, sutures impressed. All spire whorls with six rounded primary spiral cords lightly crossing about 14 very strong rounded axial ribs; ribs straight, opisthocline. Spiral cords interspaces V-shaped, much narrower than spiral cords; axial rib interspaces almost as wide as axial ribs. Anterior end of last whorl, base unknown. Aperture circular. Columella without folds. Varices and ventrolateral varix absent. Inner and outer lip unknown.

Remarks

This single specimen of Terebralia marki sp. nov. has more than the four spiral cords that are present on the specimen of T. pauli and that are typically present on species of Terebralia (but see extant T. semistriata (Mörch, 1852), which has five or six spiral cords).

Etymology

Named in recognition of Mark C. DeVries, brother of the author.

Material

UWBM 107600, holotype, B8771 (type locality), L (9.8), W (5.1).

Occurrence

Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.