Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 27i): holotype, GS2944, C46/f9487, Bluecliff, Te Waewae Bay, Southland, Kapitean (TM6795, GNS)
Beu & Maxwell (1990): Chapter 12; p. 245; pl. 27 i.
Synonymy: Ellicea willetti Fleming 1955, p. 1057
Description: Small for genus (30 mm high), robust, with rather short spire, rather short siphonal canal directed slightly to left, and evenly rounded whorls. Sculpture of prominent, narrow, flat-topped, widely and evenly spaced spiral cords only; 3 prominent cords (plus 2 weaker on sutural ramp) on spire whorls, and 10 on last whorl, with 3-4 low cords decreasing in prominence down neck. Aperture with thickened, lightly reflected lips; columellar callus bearing several low denticles. Protoconch low, dome-shaped, of 2 smooth whorls.
Comparison: Aeneator willetti is easily distinguished from other A. (Ellicea) species by its particularly prominent spiral cords. The type population completely lacks axial costae, but the middle Tongaporutuan population in southern Wairarapa referred to this species includes specimens with no axial costae and a range of specimens with weak to moderately prominent costae; possibly the Wairarapa population is intermediate between the typical A. willetti and a species resembling A. conformatus.
The Kapitean A. (Ellicea) antorbitus has weaker spiral cords and consistent, prominent axial costae; it is common in outcrops near the mouth of Waikoau River, Te Waewae Bay, close to the type locality of A. willetti, and as there are few apparent differences in facies between these localities the reason for two such distinct species of A. (Ellicea) occurring in rocks of the same age is not obvious. The rare Tongaporutuan species A. (Ellicea) henchmani and A. conformatus differ from A. willetti in being smaller, having lower, narrower spiral cords, and having prominent axial costae on early spire whorls. The poorly known A. (Ellicea) perobtusus (Opoitian, Dannevirke) is similar to A. willetti, but has axial costae. The common Pliocene bathyal index species A. (Ellicea) orbitus (= Ellicea carinata Powell, 1929; Beu 1967a, p. 106), the possibly synonymous A. wairoanus, and the closely similar Recent species A. recens (Dell, 1951) differ from A. willetti in their larger size (to more than 50 mm high), their slightly less prominent sculpture of narrower, more numerous spiral cords, and in bearing short axial costae below the suture on spire whorls, descending as low as the last whorl on at least some specimens in almost all faunules. Finally A. validus (Pl. 37j) is similar to A. antorbitus, differing in its larger size, its slightly thinner shell, its more prominent axial costae, and its prominent, horizontal, channelled sutural ramp. Most species of A. (Ellicea) are reliable indicators of a bathyal depth of deposition, but a typical species, A. succinctus (Tenison Woods, 1879), occurs in shelf facies (Muddy Creek Formation) at Muddy Creek, western Victoria (Balcombian, Middle Miocene). These earliest species, Balcombian in Australia and Tongaporutuan in New Zealand, appear abruptly and "ready-formed", so the origin of the group and whether it is really closely related phylogenetically to Aeneator are not clear.
Distribution: Kapitean, Bluecliff, Te Waewae Bay (type) and middle Tongaporutuan, Wainuioru Valley, Wairarapa.
Cite this publication as: "A.G. Beu and J.I. Raine (2009). Revised
descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990). GNS
Science miscellaneous series no. 27."
© GNS Science, 2009
(Included with a PDF facsimile file copy of New Zealand Geological Survey Paleontological Bulletin 58 in CD version from: Publications Officer, GNS Science, P.O. Box 30368 Lower Hutt, New Zealand)