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. 4l): holotype, GS9957, J40/f6608, Waihao River, Mangaorapan ? (TM5470, GNS) |
 (Pl. 4m): holotype, GS9957, J40/f6608, Waihao River, Mangaorapan ? (TM5470, GNS) |
Beu & Maxwell (1990): Chapter 6; p. 94; pl. 4 l, m.
Synonymy: Liotina turua Maxwell 1978, p. 32
Classification: Liotiidae
Description: Size moderate for genus (diameter c. 7 mm), depressed turbiniform, apex flattened. Protoconch of about 1.2 smooth whorls. Teleoconch whorls 3.5, early whorls depressed, later ones moderately elevated. A prominent keel appearing adapically at an early stage of growth, forming a broad subhorizontal shelf, then gradually descending to near middle of whorl, accompanied by a second keel between it and upper suture. A prominent peribasal keel and 2 somewhat weaker ones appearing on last whorl. Spiral sculpture, apart from cords marking the keels on later whorls, of 1 or 2 cords within umbilicus, and much finer threads between keels. Axial sculpture on early whorls of narrow, prosocline costae which bifurcate adapically; on later whorls of very prominent, broadly triangular costae which extend into umbilicus; 12-13 on penultimate whorl, 8-9 on last whorl. Between costae are numerous lamellae which initially diverge from sides of costae, but later become parallel to them, and are reticulated by spiral threads. Aperture circular, nacreous within; peristome continuous, outer lip with heavy rounded varix. Umbilicus narrower in adults than in juveniles, margin serrated by axial costae.
Comparison: Liotina turua is the only species of this characteristically warm-, shallow-water genus known from New Zealand, although the related genus Munditia Finlay, 1926 is represented in Neogene and modern faunas by several species that are much smaller than L. turua.
Distribution: Mangaorapan ?, Kauru Formation, South Branch, Waihao River, near "Pentland Hills", associated with Spondylus n. sp., Plicatula n. sp. and Costacallista hectori (see above).
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)