GNS Science

Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)

New Zealand Cenozoic Mollusca

Aethocola (Zelandiella) pliocenica (Powell, 1931)



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(Pl. 37d): holotype, GS1171, Q22/f6498, coastal cliffs 0.8 km northwest of mouth of Patea River, South Taranaki, Waipipian (TM6818, GNS)

Beu & Maxwell (1990): Chapter 14; p. 299; pl. 37 d.

Synonymy: Zelandiella pliocenica Powell 1931a, p. 102; Austrofusus (Austrofusus) pliocenicus, Beu & Maxwell 1990, p. 299, pl. 37d.

Classification: Buccinulidae

Description: Small for genus (35-40 mm high), short and wide, with low spire (half height of aperture and canal) and short, widely open anterior canal inclined strongly to left, deeply notched and strongly twisted to form very prominent, ridge-margined fasciole. Spire outline weakly stepped, with low angulation formed by row of nodules above suture; shallowly concave sutural ramp ends at low, wide subsutural fold on spire whorls, becoming more prominent over last half-whorl; last whorl descends vertically below shoulder to weak peribasal angulation, then contracts sharply to narrow neck. Sculpture of 2 low, indistinct spiral cords, one around each angulation, and remainder of surface closely sculptured with many narrow, prominent, closely spaced spiral lirae; low, rounded, closely spaced axial costae are moderately prominent on some specimens but weak on others (e.g., weak on figured specimen), forming low nodules at subsutural fold and the 2 angulating spiral cords. Aperture large; outer lip lightly thickened, smooth internally; inner lip thick, with large parietal nodule and irregularly thickened columellar callus. Protoconch small, conical, pointed, of 3.5 smooth whorls, as in other Aethocola species.

Comparison: The taxonomic position of this species group is discussed under Aethocola (Zelandiella) subnodosa (Pl. 21 i).

Distribution: Opoitian-Mangapanian; South Taranaki coast 0.8 km northwest of mouth of Patea River, Waipipian (type); abundant in the Birch's Mill shell lens, Te Waewae Bay, Southland (early Opoitian; a very near-shore shell accumulation dominated by A pliocenica, Mactra (Maorimactra) chrydaea and Lamprodomina neozelanica), and occurring less commonly in shallow-water shellbeds along the Wanganui-South Taranaki coast (Waipipian; as high as Mangapani Shell Conglomerate, basal Mangapanian), in the Mohaka River section in northern Hawke's Bay (base of sands upstream from railway viaduct; Mangapanian, accompanied by Circomphalus parvus), and in North Canterbury (Opoitian-Waipipian); rare younger than Waipipian.


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)

References

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