Notovola marwicki Finlay, 1930
FINLAY, H. J. 1930. New shells from New Zealand Tertiary beds. Part 3. Transactions and Proceedings of the New Zealand Institute, 61: 49-84, pls. 1-6. [p. 52]
«Notovola marwicki n. sp.
This differs from all the others of this group in its subobsolete sculpture on the concave valve. Instead of prominent raised ribs with more or less deeply excavated wide interstices as in fumatus, albus, meridionalis, novaezelandiae, and tainui, this species has low, lightly convex (almost flattish) ribs, with merely narrow indentations (almost sublinear grooves) between. The ribs flatten and widen still more towards ventral margin, and the interstices become wider and less definite so that near the edge the sculpture is merely a series of undulations. In shape, convexity, and interior, the right valve is practically identical with the South Australian albus Tate, but the beak is markedly broader. The left valve is also practically inseparable from albus, but the ribs are slightly broader, and the valve definitely concave. This also separates it from novaezelandiae, whose ribs on this valve are also higher and rounder. The laminae so prominent in the interstices of tainui are absent on the right valve of marwicki, but present on the flat valve, where however they are at least three to four times as numerous; densely packed, their own width or less apart, imparting a curious roughened surface to the shell. Height, 65 mm.; width, 72 mm.; thickness (1 valve), 22 mm. Locality — Castlecliff "papa" (Castlecliffian), apparently rare. Type in Finlay collection, one other specimen in N. Z. Geol. Survey collection. The Sydney (Peronian) form N. fumatus (Reeve) approaches nearest to marwicki in rounding and weakening of ribs and interstices on right valve, but it has such high and strong beaks and so convex and characteristically shaped a shell that relationship does not seem very close. The only Recent New Zealand species, novaezelandiae (Reeve), seems in some ways intermediate between tainui and marwicki, as if they had combined to produce it; both the Pliocene forms carry various sculptural features to excess, though in different ways.» HAROLD JOHN FINLAY, 1930
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