Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 20b): GS9700, J38/f9681, Sutherlands, Tengawai River, South Canterbury, Altonian (GNS)
Beu & Maxwell (1990): Chapter 11; p. 189; pl. 20 b.
Synonymy: S. spinosa Hector 1886, p. 51; S. tuberculata Hutton (in part, not of Hutton, 1873)
Description: Rather similar to S. (Struthiolaria) calcar (see above) but typically larger (height 45-70 mm) and stouter, and differing in sculptural and apertural details. The spines on the shoulder angle are considerably more prominent and usually fewer in number (8-12 on penultimate, 8-10 on last whorl) than in S, calcar, and the nodules or tubercles on the lower (peribasal) angulation are much more prominent than in any specimen of S. calcar, in some shells persisting right to the outer lip. The apertural callus is more heavily developed, with parietal callus spreading up to the shoulder angle of the previous whorl, and in some individuals, partly obscuring 1 or 2 tubercles. Some specimens have a well developed tongue-like extension to the outer edge of the inner lip callus, far more prominent than that noted on any specimen of S. calcar.
Comparison: Struthiolaria (Callusaria) callosa (Pl. 29d, e) has a much more heavily developed apertural callus than that of S. spinosa, particularly over the inner lip, with the parietal callus extending over the shoulder angle and, in some shells, up to the upper suture. Rare specimens of Callusaria from Waiauan beds in Southland (e.g., "Nissen no. 1 shellbed", Clifden) are much more like S. spinosa than S. callosa, despite their stratigraphic position, suggesting that S. spinosa has a much longer stratigraphic range than other records indicate, lived in some region not represented in the fossil record during the Clifdenian and Lillburnian Stages, and returned to Southland during the Waiauan Stage.
The relationship of the very poorly known S. (Callusaria) otaioica (Bluecliffs, Otaio River, Otaian) to S. spinosa is uncertain. Laws (1935c, pp. 41-42) distinguished his species on the basis of differences in shape and in the number of tubercles (12 on penultimate, 14 on last whorl in S. otaioica), but the importance of these differences must remain doubtful until additional material from Bluecliffs or a similar horizon becomes available.
Distribution: Altonian, Waiauan?; Altonian, Southburn Sand, White Rock River (type); Sutherlands; Ardgowan Shellbed, Oamaru; Tommy's Creek, Upper Waipara River; Waiauan, Clifden. Most common in shallow-water sandstone and shellbeds, but a few specimens recorded from deeper-water siltstone.
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)