Parvamussium clamosseum (Marwick, 1953)
MARWICK, J. 1953. Divisions and faunas of the Hokonui System (Triassic and Jurassic). New Zealand Geological Survey Paleontological Bulletin, 21: 1-141, pls. 1-17 (Corrigenda supplement: S1-S3) [p. 100, pl. 10, figs. 9, 14a, 14b]
1953 Variamussium clamosseum Marwick, 1953
J. Marwick, 1953, plate 10.
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«Shell small, outline subcircular, relatively well inflated. Right valve with anterior ear large and having a deep byssal notch, posterior ear small, oblique. Sculpture of right valve: Narrow, but strong, radial ribs, irregularly serrate on the crest, and separated by rather wider interspaces; numerous, somewhat irregularly placed concentric growth pauses interrupt the radial ribs, increasing in strength to their ends which are close to the margin. Internally, ten strong radial ribs run from the umbo to the ventral margin.
Holotype.— N.Z. Geological Survey, kindly presented by the collector, Mr G. G. Cossens, 1951.
Length, 14 mm.; height, 15 mm. ; inflation (1 valve), 3·5 mm.
Localities.— G.S. 5396, Andersons Creek, Forest Hill S.D. (type). G.S. 3144, Te Maika, Kawhia Harbour.
Stage.— Temaikan (Bajocian-Bathonian).
The generic name Variamussium has been used here because it has already been applied to Bajocian species (Paris and Richardson, 1916: 528; Cox, 1936: 19). The new species, clamosseum, has strong, serrate radials on the right valve, so that it differs from any other named group that the writer is aware of. Until the sculpture of the left valve is known, the shell can conveniently be left in Variamussium.»
JOHN MARWICK, 1953
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