Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 7e, f): holotype, GS2141, J42/f6437, Bridge Point, Kakanui, Runangan (TM4716, GNS)
Beu & Maxwell (1990): Chapter 8; p. 115; pl. 7 e, f.
Synonymy: Cardilona bensoni Marwick 1943, p. 186
Type species of Cardilona Marwick, 1943, = Pecchiolia Savi & Meneghini, 1850
Description: Moderately large for family (length 30 mm), cordate, very strongly inflated, posterior margin slightly alate dorsally. Umbones very prominent, prosogyrous, strongly incurved, projecting beyond anterior margin. Lunule triangular, slightly convex, bounded by a deep groove. Radial sculpture of about 36 low, rounded costae with narrow interspaces; commarginal sculpture of weak growth ridges. Hinge of right valve with prominent chondrophore, otherwise edentulous. Left valve not known. Other internal features unknown.
Comparison: Although still poorly known, Pecchiolia bensoni is unlikely to be confused with any other New Zealand bivalve. Marwick (1943, p. 185-186) proposed Cardilona as a genus of the obscure family Cardiliidae, but C. bensoni is so similar to species of the verticordiid genus Pecchiolia that there can be little doubt that this is where it belongs (Maxwell 1978, p. 28). The main difference between P. bensoni and other species of the genus is that the latter have more tightly coiled umbones that effectively obscure the lunule. Pecchiolia ranges from at least Late Eocene to Pliocene in Europe, and is also recorded from the Late Eocene of Wilmington, North Carolina (P. dalliana Harris in van Winkle & Harris 1919, p. 16, pl. 2, fig-7) and presumably was formerly widespread in deep water.
Distribution: Runangan, Waiareka Volcanic Formation, Bridge Point, Kakanui (type) (rare). Also doubtfully recorded from the "Isis bed", All Day Bay, Kakanui (Waitakian).
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)