Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 5k): GS9959, J40/f6610, South Branch, Waihao River, near "Pentland Hills", Bortonian (GNS)
(Pl. 5m): GS9959, J40/f6610, South Branch, Waihao River, near "Pentland Hills", Bortonian (GNS)
Beu & Maxwell (1990): Chapter 7; p. 102; pl. 5 k, m.
Synonymy: Dosinia (Kereia) mackayi Marwick 1927, p. 589
Classification: Veneridae: Dosiniinae
Description: Small for genus (height 20-30 mm), subcircular, moderately inflated. Lunule small, pouting; escutcheon better developed in left than in right valve. Sculpture of closely spaced, fine lamellae, abraded from many specimens. Left hinge with a small anterior lateral tooth, well separated from cardinals, a lamellar anterior cardinal tooth, a narrowly triangular, weakly bifid median cardinal tooth (with posterior portion more prominent) and a long, lamellar posterior cardinal tooth. Right hinge with an anterior socket, narrowly triangular anterior and median cardinal teeth (the latter somewhat the larger in most specimens) and a strongly bifid, triangular posterior cardinal tooth. Pallial sinus triangular, strongly ascending.
Comparison: Dosinia mackayi is distinguished from younger species of the subgenus by its small size and its closely spaced commarginal sculpture. Dosinia (sensu lato) is first recorded from the Wangaloan in New Zealand and is well represented in shallow-water faunules throughout the Cenozoic, but is not known in the Northern Hemisphere prior to the Oligocene. Taken at face value this suggests that it originated in the Southern Hemisphere and only much later made its way (possibly via South America) to the Northern Hemisphere, the opposite situation to the boreocentric scenario usually proposed for molluscan dispersal.
Distribution: Bortonian, Waihao Greensand, Black Point, Bortons (type) (uncommon); South Branch, Waihao River, near "Pentland Hills" (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)