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. 16e): GS9520, J41/f8024, Awamoa Creek, Oamaru, Altonian (GNS) |
 (Pl. 16g): GS9520, J41/f8024, Awamoa Creek, Oamaru, Altonian (GNS) |
Beu & Maxwell (1990): Chapter 11; p. 176; pl. 16 e,g.
Synonymy: Limopsis zealandica Hutton 1873b, p. 28
Classification: Limopsidae
Description: Size moderate for genus (height 20-28 mm), rather robust, moderately strongly inflated, shape variable, juveniles more equilateral than adults. Commarginal sculpture of rounded or imbricate growth ridges of variable strength and spacing, less prominent medially than distally or towards anterior and posterior ends. Radial sculpture of fine costellae, most prominent on posterior half, obsolete on the rest of many shells, typically more prominent on growth ridges, where they form small v-shaped ridges, than between. Cardinal area prominent, dorsal margins convex; resilifer large, broadly triangular. Hinge asymmetrical, teeth varying considerably in thickness and spacing, those in posterior series more divergent than those in anterior series. Anterior adductor muscle scar small, at distal end of hinge, bounded on inner side by a sharp myophoric ridge; posterior scar larger and set much lower, myophoric ridge absent from most specimens. Area inside pallial line roughened, with fine radial ridges. Margin smooth, broadly and sharply bevelled.
Comparison: Limopsis zealandica is distinguished from other New Zealand limopsids by its moderately large, oblique, inflated shell, by its strongly asymmetrical hinge, and by the fine radial sculpture, which is obsolete on the anterior part of the shell of most specimens. L. gisbornensis (= L. retifera Marwick, 1931; preoccupied) is similar to L. zealandica in shape but has much more prominent radial sculpture.
Distribution: Waitakian-Altonian; Mount Harris Formation, Awamoa Creek, Oamaru, Altonian (type) and other North Otago Altonian localities; Bluecliffs, Otaio River; Trig Z, Otiake; Campbell Park School, Otekaike. Common to abundant at most 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)