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. 7m): GS9481, J41/f8025, Lorne, Kaiatan (GNS) |
Beu & Maxwell (1990): Chapter 8; p. 116; pl. 7 m.
Synonymy: Maurea (Mucrinops) waiareka Laws 1935c, p. 32
Classification: Calliostomatidae
Description: Small for genus (height 10-13 mm), trochiform, spire conic, flat-sided, 0.6 total height. Protoconch not known, presumably like other species, of little more than 1 whorl. Teleoconch of about 7 flat-sided whorls with a very indistinct suture; last whorl with strongly angled periphery, base weakly convex. Spiral sculpture apparently commencing as 2 weak threads on abapical part of whorl, additional spirals appearing during growth, penultimate whorl with 5 narrow, well spaced, low cords, the 2 abapical pairs with a single interstitial thread, the lower of which becoming almost as strong as the cords on last whorl. All spirals distinctly beaded, except for fine thread appearing between 2nd and 3rd cords (counting from adapical end) on last whorl. Base with 3 weak threads near periphery and 8-10 nodulose cords between them and aperture, most of them stronger than cords on whorl sides. Aperture subquadrate, columella oblique, slightly concave.
Comparison: Calliostoma waiareka is similar to C. acutangulum (Duntroonian, Castle Hill Basin) in shape but has a much less distinct suture, and lacks definite radial sculpture on the base. The regularly conic shape, flat-sided whorls, and weakly defined suture, and the absence of definite axial sculpture set it apart from other mid-Cenozoic species, but like them it is distinguished from most of the late Cenozoic calliostomatids by its relatively small size. This is the oldest definite member of the family and genus to have been named from New Zealand, but an undescribed species is present in the View Hill Volcanics at White's Creek, North Canterbury (Mangaorapan) (B.A. Marshall, pers. comm.). Although most New Zealand members of the family were assigned to Calliostoma (Maurea) by Marshall (1995), the relationships of these small fossil taxa to Calliostoma needs clarification, and pending the extension of his revision to the fossil Calliostomatidae by B.A. Marshall (Museum of New Zealand Te Papa Tongarewa) we have assigned them to Calliostoma (Maurea). Williams et al. (2007) recognised Calliostomatidae as a full family.
Distribution: Kaiatan, Waiareka Volcanic Formation, Lorne (type) (uncommon).
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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