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. 31a): Acanthochitona (Notoplax) n.sp.A aff. latalamina; Mangahao River, west of Pahiatua, northern Wairarapa, Mangapanian (National Museum of N.Z.) |
 (Pl. 31d): Acanthochitona (Notoplax) n.sp.A aff. latalamina; Mangahao River, west of Pahiatua, northern Wairarapa, Mangapanian (National Museum of N.Z.) |
 (Pl. 31g): Acanthochitona (Notoplax) n.sp.A aff. latalamina; Mangahao River, west of Pahiatua, northern Wairarapa, Mangapanian (National Museum of N.Z.) |
 (Pl. 31c): Acanthochitona (Notoplax) n.sp.B aff. latalamina; cliffs east of Lake Ferry, Palliser Bay, southern Wairarapa, Mangapanian or Nukumaruan (GNS, ex D. Cowe collection) |
Beu & Maxwell (1990): Chapter 14; p. 274; pl. 31 a,c,d,g.
Synonymy: Acanthochitona (Notoplax) n. spp. A, B, Beu & Maxwell 1990, p. 274, pl. 31a, c, d, g.
Classification: Acanthochitonidae
Comparison: The characters of the genus are discussed under Notoplax mariae (Pl. 44 a, d, h). The Recent N. latalamina (Dell) (1956a, p. 57) is a large, slug-like chiton to about 70 mm long, with huge sutural laminae and small, finely sculptured tegmental areas, and its extremely wide girdle is densely felted with siliceous spicules. It has been dredged uncommonly in deep water (200-300 m) in the Cook Strait area, usually on sponges. It is closely related to the typical Australian Notoplax species, which have wide, spiculous girdles and reduced tegmenta. We have seen two lots of valves of A. (Notoplax) species that appear to represent unnamed species with wide girdles and very restricted tegmenta, similar to the living A. latalamina.
One lot of numerous valves (A. (Notoplax) n.sp. A, Pl. 31a, d, g) includes all three valve types; they differ from valves of large adult A. latalamina in being only half as large, in having slightly larger tegmenta and smaller sutural laminae, in having markedly larger tegmental granules but very much weaker radial ridges between lateral and pleural areas of median valves, and in having unusually weak radial ridges on the anterior valve for a species of Notoplax. They are from a shallow-water facies with abundant, diverse Mollusca.
The other is a single median valve (Notoplax n.sp. B, Pl. 31c) of similar size and similar tegmentum-sutural laminae proportions to the Mangahao River specimens, but differs in its much narrower jugum and still coarser tegmental granules. The specimen is from bathyal siltstone and appears to have lived in an environment much more like that of N. latalamina than that of the Mangahao River specimens.
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
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copy of New Zealand Geological Survey Paleontological Bulletin 58 in CD version
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