Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 2c): holotype, Boulder Hill, Wangaloan (Auckland Museum)
(Pl. 2d): holotype, Boulder Hill, Wangaloan (Auckland Museum)
Beu & Maxwell (1990): Chapter 5; p. 81; pl. 2 c, d.
Synonymy: Spirogalerus lamellaria Finlay & Marwick 1937, p. 46
Type species of Spirogalerus Finlay & Marwick, 1937
Description: Size moderate for family (height 20-30 mm), crepiduloid. Protoconch eroded in all known specimens; teleoconch of 3-4 whorls; spire low, strongly exsert. Suture strongly impressed, descending rapidly on last whorl. No sculpture apart from rather sinuous growth lines. Aperture very large, elongate-ovate with a prominent concave septum well within, forming a shallow depression ("false umbilicus") at junction with upper wall.
Comparison: Sigapatella (Spirogalerus) lamellaria differs from typical species of Sigapatella in having a very strongly exsert spire and an elongate-ovate rather than a subcircular aperture. Although Finlay & Marwick (1937) gave Spirogalerus generic rank, the differences between it and Sigapatella (sensu stricto) are rather minor and do not seem to warrant more than subgeneric differentiation. Finlay & Marwick (1937, p. 46) and Boshier (1960, p. 390, fig. 3) considered S. lamellaria to be the probable ancestor of Sigapatella (sensu stricto), which is first recorded from beds of probable Early Eocene age in the upper Waihao River. However, Saul & Squires (2008) suggested a close relationship with Lysis Gabb, 1864 ("Trichotropidae": Lysinae) rather than with Calyptraeioidea (but note that Trichotropis is included in Capulidae by Bouchet et al. (2005, p. 250)).
Distribution: Wangaloan, Boulder Hill (type) (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)