Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
| | Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990) |
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  (Pl. 26e): GS10365, D45/f8598, Long Beach Shellbed, Clifden, Altonian (GNS) |
Beu & Maxwell (1990): Chapter 11; p. 234; pl. 26 e.
Synonymy: Austrotoma clifdenica Powell 1942, p. 42
Classification: Turridae: Pseudotominae
Description: Size moderate for genus (height 30-45 mm), fusiform, spire half total height. Protoconch similar to that of A. excavata, but much larger. Teleoconch of 5-6 whorls, strongly shouldered near middle on spire, periphery rather broad, somewhat projecting in some shells; sutural ramp strongly concave, with pronounced subsutural fold. Axial sculpture on early whorls of narrow costae reaching from periphery to lower suture, but on later whorls consisting of rounded peripheral nodules, subobsolete or obsolete below; 10-13 per whorl. Spiral sculpture of fine threads on sutural ramp, and prominent, crisp cords below, some with interstitial threads, crossed and slightly granulated by growth lines. Aperture with deep siphonal notch; fasciole prominent, sunken, bordered above by a low, sharp ridge.
Comparison: Austrotoma clifdenica is readily distinguished from similar species by the rather coarse peripheral nodules on adult whorls, and by the prominent spiral sculpture. Specimens from lower in the Clifden Section (e.g., from the Fouraye Siltstone, Altonian) have very similar spiral sculpture to typical A. clifdenica, but have axial costae confined to the first three or four whorls. They appear to be conspecific with shells from Altonian siltstone on the north shore of Parengarenga Harbour, Northland.
Distribution: Altonian-Clifdenian; Long Beach Shellbed, Clifden, Altonian (type); Calamity Point Sandstone and Slip Point Siltstone, Clifden; Postal Creek, Karamea district; ? Alexander Street, Greymouth. Not uncommon at Clifden localities.
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)