Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 41i): holotype, GS1063, V21/f8476, Okauawa Stream, Kereru Road, central Hawke's Bay, Nukumaruan (TM6769, GNS)
Beu & Maxwell (1990): Chapter 15; p. 318; pl. 41 i.
Synonymy: Ataxocerithium suteri Marwick 1924c, p. 195
Type species of Taxonia Finlay, 1926
Description: Small for family (10-18 mm high), very tall and narrow, with small aperture, very tall spire of 8 short whorls, weakly impressed suture, and almost flat-sided whorls. Sculpture of 3 prominent, wide spiral cords per whorl, crossed by prominent, closely spaced axial costae, 14 on early whorls, 16 on penultimate and 17 on last whorl, forming large, subcircular, radially flattened nodules at sculptural intersections; an interstitial, nodulous spiral cord develops between uppermost 2 primary cords on last whorl. Anterior canal short, narrowly open, strongly twisted but without obvious fasciole. Aperture with 3 very prominent, wide spiral ridges inside outer lip (2 high up and 1 near base), 2 similar ridges on parietal area, and 1 on base of columella. Protoconch not known.
Comparison: The Waipipian Taxonia tesserata is larger than T. suteri, with subtly different sculpture (recorded only from Otahuhu Brewery well, Auckland). The Tongaporutuan T. gudrunae from Mt Bruce, northern Wairarapa, is smaller than T. suteri, with a more convex spire outline. Very similar, unnamed species occur in estuarine mud lenses in conglomerate at Putangirua Stream, Palliser Bay (early Tongaporutuan), in the Enys Formation (Altonian) in Porter River, Castle Hill Basin, Canterbury, and in Chatton Formation (Duntroonian) in a new pit near Waimumu, Southland.
Distribution: Mangapanian-Nukumaruan; Okauawa Stream, Kereru Road, inland central Hawke's Bay, Nukumaruan (type). A very distinctive little shell, known only as severely abraded, clearly transported shells in very shallow-water facies, common in Okauawa Stream, Hawke's Bay, and in Tangoio Limestone at Petane, north of Napier, and found uncommonly in a few Mangapanian-Nukumaruan estuarine beds. Taxonia was apparently an estuarine genus. Another genus and species whose extinction provides a good indication of the end of the Nukumaruan Stage.
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)