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. 2t): GS10195, I44/f8486, Boulder Hill, Wangaloan (hypotype of Finlay & Marwick 1937, pl. 9, fig. 16) (GNS) |
Beu & Maxwell (1990): Chapter 5; p. 83; pl. 2 t.
Synonymy: Phos ordinarius Marshall 1917, p. 456; P. conicus Marshall 1917, p. 456; Pseudofax ordinarius ordinarius; P. ordinarius conicus
Type species of Pseudofax Finlay & Marwick, 1937
Classification: Buccinulidae
Description: Small for family (height 10-20 mm), elongate-ovate. Protoconch broadly conical, of about 3 convex whorls, too worn in available material to tell if sculpture originally present. Teleoconch whorls 5-6 in adult, evenly convex or obtusely angled near middle on spire; base of last whorl excavated, with short neck. Axial sculpture of low, rounded, orthocline, slightly opisthocyrt costae, c. 14-20 on penultimate whorl, not extending onto base of last whorl. Spiral sculpture of narrow, low cords of variable number and spacing, over-riding axial costae with little or no change. Aperture ovate, inner lip moderately callused, with a weak ridge margining a short, open, notched siphonal canal. Fasciole well developed, margined above by a narrow ridge. Outer lip thin, lirate within.
Comparison: Pseudofax ordinarius is a highly variable species, some specimens resembling the figured one in having a slender shell, distinctly angled teleoconch whorls and relatively prominent axial sculpture; others ("conicus" type) having a stumpier habit with convex whorls and subdued axial sculpture and looking rather like a nassariid. Finlay & Marwick (1937, p. 80) recognised the variation in this species but retained Marshall's names (as subspecies) for the extreme morphotypes. They were synonymised by Beu & Maxwell (1990, p. 83) in keeping with contemporary taxonomic ideas, in which such forms are considered to be part of the variation of one species.
Pseudofax is a rather generalised buccinid of the Cominella-Fax type. It is similar in general appearance to Fax Iredale, 1925 (Recent, Australia) but differs in having a broadly conical rather than a cylindrical protoconch. The genus is also recorded from faunules of probable late Dannevirke Series age (Heretaungan or Porangan?) i.e. Castle Hill Shaft, Kaitangata; "Island Sandstone", Waihao River (Finlay & Marwick 1937, p. 107, 120) and Otaio Gorge (Marwick 1960, p . 22) but has not been reported from Bortonian assemblages. Recorded also from Paleocene rocks of Argentina by Griffin & Hünicken, 1994) and, less convincingly, from Eocene rocks of Seymour Island, Antarctic peninsula (Stilwell & Zinsmeister, 1992).
Distribution: Wangaloan, Wangaloa Formation, Wangaloa (type locality of both nominal species); Boulder Hill (common at both localities).
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)