GNS Science

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

New Zealand Cenozoic Mollusca

Struthiolaria incrassata Powell, 1931


(Pl. 36o): Waihi Beach, Hawera, South Taranaki, Waipipian (GNS, ex F.D. Chambers Collection)

Beu & Maxwell (1990): Chapter 14; p. 294; pl. 36 o.

Synonymy: Struthiolaria incrassata Powell 1931a, p. 101; Pelicaria incrassata, Beu & Maxwell 1990, p. 294, pl. 36o.

Classification: Struthiolariidae

Description: Very small for genus (23-27 mm high), with spire about equal in height to aperture, with shallow, narrow, but obvious, ridge-margined sutural channel, and with normal Pelicaria aperture with weakly sinuous, varicate outer lip meeting thickened, narrow inner lip at shallow anterior notch. Sculpture of 3 spiral cords only; the uppermost a prominent carina forming a shoulder at 0.6 whorl height on spire, the middle one a prominent carina around peribasal angle, and the third a much lower one close below the second, at top of base. A few faint spiral threads present elsewhere on some specimens, and on base of most specimens, but most have a wide, steeply inclined, weakly concave sutural ramp, and a wide, deeply concave whorl outline between the 2 major carinae. A few low nodules on shoulder carina of some specimens. Protoconch low, paucispiral, typical of genus.

Comparison: Struthiolaria incrassata is extremely distinctive because of its small size and only two prominent spiral cords. The Opoitian Pelicaria parva is similar (presumably superficially) but has a third prominent, narrow carina midway between the two major ones of P. incrassata, and all specimens have a nodulose upper carina. The lack of any sign of a median carina and the unusual, thick, reflexed terminal varix indicate that S. incrassata is a small species of Struthiolaria rather than a weird species of Pelicaria.

Distribution: Waipipian; Waihi Beach, Hawera, South Taranaki (type), common here and at a few nearby localities in inner-shelf blue-grey sandstone along the Wanganui-South Taranaki coast.

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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