Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 9a): GS9535, J42/f6031, beach below Everett's Quarry, Kakanui, Whaingaroan (GNS)
Beu & Maxwell (1990): Chapter 9; p. 131; pl. 9 a.
Description: Rather small for genus (height 35-40 mm), right valve somewhat more inflated than left. Dorsal margins of left valve colinear, those of right valve divergent, slightly serrate; byssal notch deep. Proximal 10-12 mm of both valves smooth except for commarginal striae and "Camptonectes" sculpture, remainder with 41-44 narrow, rounded to squarish primary costae which become scaly distally. Scaly secondary costellae appearing between costae and near dorsal margins, about halfway across disc. Ears with fine scaly costellae. Hinge with broad resilifer, prominent cardinal crurae and well developed provinculum.
Comparison: The new species resembles Serripecten tiorioriensis (Pl. 4b) in its small size and relatively simple sculpture, but has more numerous radial costae and has secondary costellae appearing at a much earlier stage of growth. S. enfieldensis (Kaiatan-Runangan, North Otago) has less numerous costae (26-29), which commence much closer to the beaks (c. 5 mm). The presence of similar radial costae on both valves places this species in Waller's (2006, p. 16) group of taxa unrelated to Serripecten, being unrelated scallops with fine, scaly sculpture. This group requires further study, but in New Zealand probably represents an unnamed genus of Chlamydini rather than Serripectinini.
Distribution: Whaingaroan, Deborah Volcanic Formation, Everett's Quarry, Kakanui (common).
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)