Saturday, March 30, 2013

Acanthoscapa devonica ostracod from the Centerfield Fm.

Parsing through a sample of the Centerfield Limestone looking for microfossils, I was pleasantly surprised to find some small "rice grains". They didn't look like Ostracods to me because they were not round nor did they have any ornamentation to them. A quick scan through the book "Ostracods of the Middle Devonian Silica Formation" changed my mind.

These are a species called  Acanthoscapa devonica. Each fossil is about 2mm long. If I did my math right, the full size image is 50x (since the fossils are shown 100mm long on my screen)

According to the book (vol 1, pg 86) They are known from the Silica Shale but have also been found in the Hungry Hollow member of the Widder Formation in Ontario as well as the Centerfield member of the Ludlowville Formation in New York. They are illustrated on plate 7 (vol 2, pg. 16-17) where there is a comment that the specimen shown is from the Hungry Hollow formation and that specimens from the Silica shale often have their ends broken off.

References: "Ostracods of the Middle Devonian Silica Formation" by Kesling, R. V.; Chilman, R. B, 1978, FUMMP Papers on Paleontology No. 18

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