Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 8z): GS11,200, J40/f8853, Kapua Tuff, Waihao River, Kaiatan (GNS)
Beu & Maxwell (1990): Chapter 8; p. 128; pl. 8 z.
Synonymy: Avellana tertiaria Marshall 1916b, p.121 (not of Vincent, 1884); Superstes marshalli Finlay & Marwick 1937, p. 109, p. 120 (new name for Avellana tertiaria Marshall, preoccupied); Gilbertia tertiaria
Description: Moderately large for family (height 7-9 mm), ovate, spire low, dome-shaped, 0.2-0.3 total height. Protoconch depressed dome-shaped of about 2 smooth whorls. Teleoconch of about 3 whorls, moderately convex on spire, with impressed sutures; last whorl large, strongly inflated. Sculpture of narrow spiral grooves with broad, flat interspaces, typically constricted at regular intervals to form punctate sculpture of shallow, oval pits; 20-27 grooves on last whorl. Aperture pyriform, strongly constricted posteriorly; columella concave, bearing 2 strong plaits, a vertical one bordering the shallow siphonal notch and a nearly horizontal one near adapical end. A third strong plait on lower part of parietal region. Inner lip prominently callused, with a heavy, rounded ridge running along its edge from top of columella almost to adapical end of aperture. Some shells with a very short ridge or tubercle above parietal plait and within aperture. Outer lip slightly prosocline, thickened externally by broad, rather low varix, padded within, bearing 2 strong denticles on abapical half (interspace smooth or with up to 3 weak denticles), and up to 10 weaker ones above.
Comparison: Superstes phoenix (Kaiatan, Lorne), the type species of Superstes Finlay & Marwick, 1937, is very similar but differs in having a prominent vertical ridge rather than a very short ridge or tubercle in the parietal area.
Superstes is a restricted New Zealand genus, apparently closely related to Gilbertina Morlet, 1888, which occurs in the Paleocene to Miocene of the Northern Hemisphere, but differing from Gilbertina in having a much less strongly prosocline outer lip, and a distinct siphonal notch. Both genera differ from Ringicula (Pl. 56i, j) in their larger size and more globose, lower-spired shell and in having a prosocline rather than an opisthocline outer lip. Their closest relationship seems to be with Late Cretaceous taxa such as Avellana Orbigny, 1843 and Eriptycha Meek, 1876.
Distribution: Bortonian-Kaiatan; Bortonian, Hampden (type); Waihao Greensand, McCulloch's Bridge (rare); Kapua Tuff, Waihao River (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
(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)