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. 22b): GS9520, J41/f8029, Awamoa Creek, Oamaru, Altonian (GNS) |
Beu & Maxwell (1990): Chapter 11; p. 207; pl. 22 b.
Synonymy: Marginella (Glabella) conica Harris 1897, p. 88-89; Protoginella (Protoginella) conica, Beu & Maxwell 1990, p. 207, pl. 22b.
Classification: Marginellidae
Description: Size moderate for family (height 4.8-7.5 mm), strombiform, spire conic, 0.25-0.3 total height. Sutures largely obscured by callus, teleoconch of about 3 whorls, bluntly shouldered near middle on spire, sutural ramp slightly concave; last whorl shallowly excavated anteriorly. Surface polished, no sculpture. Aperture narrow, elongate; anterior end truncate or slightly convex, no notch or sinus. Inner lip callus thin, spreading across much of ventral face of last whorl, around top of aperture and behind outer lip, but in many specimens difficult to distinguish from rest of shell. Columella with 4 prominent plaits, the lowest bordering the short siphonal spout. Outer lip with shallow sinus between suture and prominent shoulder angle, thickened externally, inner edge prominently denticulate.
Comparison: Protoginella conica is readily distinguished from other New Zealand marginellids by its biconic shell with a prominently shouldered and denticulate outer lip, and its prominent columellar plaits. Protoginella ranges from at least Kaiatan to Waiauan, and possibly to Opoitian in New Zealand. The type species (P. valida (Watson, 1886) (northern Australia) lives in shallow waters, but all of the New Zealand records are from mid-shelf to upper bathyal faunules. Maxwell (2009) adopted the classification of Coovert & Coovert (1995) for marginelliform gastropods, and is followed here.
Distribution: Altonian; Mount Harris Formation, Awamoa, Oamaru (type) and other localities in Oamaru district, at most localities common or abundant and occurring with the similar-sized Mesoginella harrisi (see below).
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)