Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 5p): holotype, Hampden Beach, North Otago, Bortonian (TM4795, GNS)
Beu & Maxwell (1990): Chapter 7; p. 104; pl. 5 p.
Synonymy: Trigonia areolata Marshall 1919, p . 234
Type species of Kurinuia Marwick, 1942
Description: Size moderate for family (length 15-20 mm), ovate, strongly inflated, interior nacreous; beaks markedly prosogyrous. Lunule small, deeply impressed; posterior area well differentiated. Radial sculpture of 15-16 prominent rounded costae with interspaces similar in width to or distinctly narrower than costae, on flanks and anterior end. Costae smooth or with fine commarginal ridges anteriorly. Posterior area with a prominent radial costa near dorsal margin and a much narrower costa (or groove on some shells) anteriorly; remainder sculptured with closely spaced commarginal ridges. Internal features poorly known; right valve with a prominent triangular cardinal tooth and a strong posterior lateral tooth. Ventral margin coarsely crenulate.
Comparison: This distinctive bivalve was originally described as a species of Trigonia, probably because of the nacreous interior and the strongly differentiated posterior area. This would have been an exceptionally interesting occurrence if this assignment was correct, as the only other post-Cretaceous records of the family are from Australia and New Guinea (see Darragh 1986 for a review). However, Kurinuia areolata lacks the characteristic trigoniid dentition and is prosogyrous rather than orthogyrous or opisthogyrous. Two other species of "Trigonia" were described from Hampden T. neozelanica and T. densicostata but both are now referred to the Verticordiidae.
Distribution: Bortonian, Hampden Formation, Hampden Beach (type) (rare).
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)