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. 24h): Long Beach Shellbed, Clifden, Altonian (M27900, National Museum of NZ) |
Beu & Maxwell (1990): Chapter 11; p. 220; pl. 24 h.
Synonymy: Maoricolpus ongleyi Marwick 1931, p. 93
Classification: Turritellidae
Description: Very large for family (height 100-170 mm), narrowly conical, with a relatively wide spire angle, spire 0.85 total height. Protoconch very small, conical, of about 3 strongly convex whorls. Teleoconch of 10-15 whorls of variable shape, weakly campanulate, frustate or subcylindrical. Spiral cords B and C appearing at beginning of teleoconch, B dominant for a few whorls, A appearing later, rivalling C in strength for a while (thereby giving whorls a biangulate profile) but then like B fading into "background" spirals; C remaining distinct for several whorls then to becoming indistinguishable from supernumary spirals, although its position is marked by a narrow anterior cingulum on many shells. Subadult and adult whorls covered with numerous, closely spaced, subuniform spiral cords. Well preserved shells with very numerous fine, lamellar axial ridges that give adult whorls a finely rasp-like texture; those on crests of spiral cords more or less collabral, but some in interspaces of adapical cords distinctly opisthocline and hence, non-collabral. Sinus moderately deep, abapical limb steeper than adapical limb.
Comparison: Maoricolpus ongleyi is readily distinguished from other large turritellids by its relatively wide spire angle, by the subadult and adult spiral sculpture of numerous subuniform cords, and by the non-collabral interstitial ridges. M. waitemataensis (Otaian, Waiheke Island) is related, but is considerably smaller (height 70-80 mm), has a narrower spire, and has finer, weaker spirals on the whorl sides but considerably stronger cords on the base.
Distribution: Otaian-Kapitean; Island Creek, Waipaoa River, Gisborne district, Lillburnian (type); and from numerous localities in North and South Islands. The youngest record is from the Kapitean of Maruhou Point, east of Te Araroa, East Cape (in Museum of N.Z. Te papa Tongarewa). Not recorded from the Altonian of North Otago and South Canterbury, where other "giant" turritellids (e.g. Tropicolpus abscisus and T. (Amplicolpus) cavershamensis) are common.
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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