Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 14c): excavation for mysticete whale, Sister's Creek, Hakataramea Valley (Duntroonian) (G. Mason Collection)
(Pl. 14g): excavation for mysticete whale, Sister's Creek, Hakataramea Valley (Duntroonian) (G. Mason Collection)
Beu & Maxwell (1990): Chapter 10; p. 155; pl. 14 c, g.
Description: Moderately large for genus (diameter 50-58 mm, not including spines), spire very low, gently convex. Periphery strongly keeled, with long, narrow, solid, oval-sectioned, strongly forward- directed spines protruding horizontally. Suture undulating strongly around bases of spines on previous whorls. Base gently convex except for a deeply concave depression in central quarter formed by thin, smooth callus filling umbilicus. Sculpture of many rows of closely spaced, low, rounded gemmules, coarsest near upper suture and becoming very fine just above peripheral spines; outer third of base almost smooth, with very low, indistinct radial costae and spiral threads. Columella thick, smooth; basal lip strongly excavated; outer lip swinging strongly forward from spines, then retracting strongly to suture, forming a marked sinus. Operculum thin, flat, oval, almost smooth, with low marginal ridge and weak "finger-print" sculpture.
Comparison: The oval, almost flat, smooth operculum is found in the aperture of many specimens. This is a large, typical species of Guildfordia close to the living type species, G. triumphans (Philippi) (tropical western Pacific, from northern Australia to southern Japan), but differing in its larger size, its lower spire, its more numerous spines (nine or 10 on last whorl, rather than seven in G. triumphans), and its larger and deeper umbilical hollow. This is apparently the earliest true Guildfordia (sensu stricto) yet reported and is the only undoubted record from New Zealand.
Distribution: Duntroonian-Waitakian; several localities in Otekaike Limestone in North Otago and South Canterbury, around Waitaki and Hakataramea Valleys, in shallow (inner-mid shelf) soft-bottom facies.
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)