GNS Science

Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)

New Zealand Cenozoic Mollusca

"Cyclocardia" awamoensis (Harris, 1897)


(Pl. 17h): GS9520, J41/f8029, Awamoa Creek, Oamaru, Altonian (GNS)


(Pl. 17i): GS9520, J41/f8029, Awamoa Creek, Oamaru, Altonian (GNS)

Beu & Maxwell (1990): Chapter 11; p. 184; pl. 17 h,i.

Synonymy: Venericardia intermedia Hutton 1873b, p. 24 (secondary homonym of Chama intermedia Brocchi, 1814; Venericardia intermedia of Borson, 1825); Cardita awamoensis Harris 1897, p. 360 (new name for Venericardia intermedia Hutton 1873, preoccupied); V. pseutes Suter 1917, p. 73; V. awamoaensis; V. (Megacardita) awamoensis; V. (Cyclocardia) awamoensis

Classification: Carditidae: Venericardiinae

Description: Size moderate for family (height 30-40 mm), ovate-subquadrate, moderately inflated, typically longer than high. Lunule very small, deeply impressed, its margin sloping strongly backwards; escutcheon narrow, vertical. Radial sculpture of 21-24 prominent costae, rounded or somewhat flattened, with interspaces of similar width, over proximal half of shell but becoming lower, more rounded and less well defined towards ventral margin. Crests with fine nodules on umbones, later smooth or with fine growth lines. Left hinge with thin, strongly backward- sloping anterior cardinal tooth and a long, thin, slightly arched posterior cardinal. Right hinge with low, tubercular anterior cardinal tooth that is almost completely obsolete in some shells, a rather narrow, slightly arched median cardinal, and a lamellar posterior cardinal that in many shells is barely distinguishable from nymph.

Comparison: Specimens of "Cyclocardia" from the Wharekuri Greensand at the head of Lake Waitaki (Duntroonian) are similar to Altonian shells in most characters, but most specimens are larger (height up to 50 mm) and have more numerous (25-27) radial costae. They may represent an unnamed species. "Cyclocardia" christiei (Pl. 10g, i) is larger and more oblique than C. awamoensis, and has more prominent radial sculpture.

Distribution: Duntroonian?, Altonian; Mount Harris Formation, Altonian, Awamoa Creek (type locality of C. awamoensis), very common here and at many localities in North Otago and, less commonly, in South Canterbury. Type of V. pseutes from "Oamaru".

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
ISBN 978-0-478-19705-1
ISSN 1177-2441
(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)


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