Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 9e): GS9535, J42/f6031, beach below Everett's Quarry, Kakanui, Whaingaroan (TM5421, GNS - specimen figured by Beu & Ponder 1979, fig. 11a-c)
(Pl. 9j): GS9535, J42/f6031, beach below Everett's Quarry, Kakanui, Whaingaroan (TM5421, GNS - specimen figured by Beu & Ponder 1979, fig. 11a-c)
Beu & Maxwell (1990): Chapter 9; p. 134; pl. 9 e, j.
Synonymy: Turbo marshalli Thomson 1908, p. 103; Incilaster marshalli
Type species of Incilaster Finlay, 1926, synonymised by Beu & Maxwell (1990, p. 134) with Ormastralium Sacco, 1896
Classification: Turbinidae: Turbininae
Description: Size moderate for genus (height up to 30 mm), trochiform, spire conic, stepped, 0.6 total height. Protoconch not clearly differentiated in available material; teleoconch of about 5 or 6 whorls, apex flat, later whorls with a well marked sutural shelf at or somewhat below suture and a prominent keel close to lower suture (fused to succeeding whorl in some shells). Last whorl with a prominent peribasal keel and an almost flat base with a large, central, flat callus pad extending more than half diameter of shell. Sculpture of short triangular spines on peripheral keel (about 12 per whorl) and several closely spaced rows of small rounded or rather sharp nodules, largest on edge of sutural shelf, alternating in strength on whorl sides, but nodules more even on base. Aperture strongly prosocline, outer lip lightly flared on large specimens. Operculum thick, weakly convex, with weakly pustulose sculpture.
Comparison: Specimens from the Waiareka Volcanic Formation at Lome (Kaiatan) have a more marked sutural channel, flatter whorl sides, a slightly taller spire, more evenly granulose sculpture and shorter peripheral spines than Kakanui specimens of Bolma marshalli, and probably represent an unnamed but closely related species. Other poorly known, unnamed species of the subgenus are recorded from the Kauru Formation, North Otago (Teurian ?), the Greymouth area (Clifdenian) and the shore platform east of Te Araroa, East Cape (Kapitean). Beu & Ponder (1979) referred Bolma species to two informal "species groups", but previous authors had regarded these as different subgenera (or genera), and in our opinion they are worth recognising at the subgeneric level. Typical Bolma (= Oobolma Sacco, 1896 and Galeoastraea Habe, 1958) reaches a markedly larger size and has more rugose sculpture and, in many species, much larger peripheral spines than the smaller, more-or-less evenly granulose species of B. (Ormastralium). Beu & Ponder (1979) pointed out that B. marshalli is closely similar to the species group of B. guttata (A. Adams, 1863), which is now widely distributed in the Indo-West Pacific province, from South Africa to the Kermadec Islands and Japan. One member of this group, B. (Ormastralium) recens (Dell, 1967), is recorded from depths of about 350-700 m between New Zealand and the Kermadec Islands and on the Norfolk Ridge.
Distribution: Whaingaroan, Deborah Volcanic Formation, Everett's Quarry, Kakanui (type) (moderately 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)