Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 37m): holotype, GS4253, Q22/f7544, basal sand member of Upper Waipipi Shellbed, Waverley Beach, west of Wanganui, Waipipian (TM5098, GNS)
Beu & Maxwell (1990): Chapter 14; p. 299; pl. 37 m.
Synonymy: Nassicola ultima Beu 1973b, p. 325
Description: Large for genus (55-60 mm high), with tall, narrow, weakly stepped spire, and very short, widely open, strongly twisted anterior canal with deep anterior notch, producing low, rounded fasciole margined by very prominent, narrow, sharp ridge. Whorl outline with broadly rounded shoulder angle (at upper third on spire whorls) and moderately wide, shallowly concave sutural ramp; last whorl with strongly rounded periphery, contracting strongly below to marked short neck. Sculpture of low, relatively widely spaced, indistinct spiral cords, moderately prominent on sutural ramp and base but obsolescent over central area of last whorl; crossing prominent, rounded, widely spaced axial costae that do not descend below periphery of last whorl. Outer lip thickened and bearing a row of about 17-18 low, short ridges within, thin at edge; inner lip thick but smooth. Protoconch not well preserved but clearly conical, small and sharply pointed, of about 3.5-4 whorls.
Comparison: Nassicola ultima resembles Cominella species in its tall spire, its very short, strongly twisted canal, and its prominent fasciole, but it has the small, multispiral, conical protoconch of Aethocola and Nassicola, rather than the paucispiral, dome-shaped protoconch of Cominella. It was the last of a long-lived group of species beginning with the Wangaloan N. sublurida; the several Miocene species (e.g., N. finlayi, Pl. 21m) are all smaller and have longer anterior canals and shorter spires than N. ultima.
Distribution: Tongaporutuan-Waipipian; basal sand member of Upper Waipipi Shellbed, Waverley Beach, west of Wanganui, Waipipian (type), moderately common; sandstone in road cuttings on hill south of Te Araroa, East Cape, Tongaporutuan; uncommon in Opoitian diverse shelf assemblages in the Gisborne district.
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)