Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 6r): South Branch, Waihao River, near Waihao Downs, Bortonian (GNS, ex C.R. Laws Colln.)
Beu & Maxwell (1990): Chapter 7; p. 110; pl. 6 r.
Synonymy: Surcula sertula Suter 1917, p. 53
Classification: Turridae: Turrinae?
Description: Size moderate for family (height 23-50 mm), fusiform, spire about half total height. Protoconch not known. Teleoconch of about 9 whorls, weakly shouldered near middle on spire, sutural ramp steep, slightly concave with low subsutural fold; last whorl broadly excavated, contracted to moderately long neck. Axial sculpture on early whorls of very short, low, rounded costae reaching from middle of ramp to lower suture; on later whorls costae changing gradually into low, broad, rounded nodules on shoulder and eventually becoming obsolete; 8 or 9 per whorl. Spiral sculpture subdued, consisting of a narrow cord on lower edge of subsutural fold, another on shoulder angle and 8-10 of similar strength on base and neck of last whorl; also background sculpture of very numerous, exceedingly fine threadlets over shell surface. Aperture narrowly pyriform, columella almost straight, oblique. Inner lip smooth, slightly impressed adapically; outer lip thin with a rather shallow anal sinus, its apex rounded and near middle of ramp.
Comparison: This species is somewhat doubtfully referred to Insolentia because its anal sinus is broader and less symmetrical than in typical species of the genus. It superficially resembles some species of Comitas but differs in having a much shallower sinus.
Distribution: Porangan?; Bortonian, Waihao Greensand, Waihao Downs (type) (not uncommon); Hampden Beach; Pareora River; Otaio Gorge(?).
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)