Thursday, November 24, 2011

Striispirifer niagarensis from Lockport, NY

One of the larger brachiopods found in the Irondequoit limestone Rochester Shale is Striispirifer. I haven't found too many whole specimens but the one shown below retains the form and shape.

Pedicle valve


Brachial valve



Striispirifer is in the same family of brachiopods as Eospirifer and you can see in the pic below minute striations on the shell that are reminiscent of Eospirifer radiatus. The difference between the two is that Eospirifer radiatus has a larger interarea between the posterior of it's valves and Striispirifer has prominent folds radiating from the hinge line.

Here is another specimen that is still encased in rock. The fine radiating lines on the shell are very nicely displayed.

Based on the image at the NY Paleontology website, I'm calling this Striispirifer niagarensis. The Irondequoit limestone Rochester Shale is middle Silurian in age (Wenlock series, Sheinwoodian stage).

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