Sunday, July 5, 2015

Macropleura macropleura brachiopod from the Kalkberg formation of New York

If I may paraphrase the song "New York, New York" by Gerard Kenny, Macropleura is a brachiopod so nice, they named it twice! Macropleura macropleura is a large brachiopod and hard to mistake for something else in the Kalkberg formation. I've found similar specimens from the Licking Creek formation of  Virginia but there they were silicified. Despite its large size, I've yet to find any whole, articulated specimens. The specimens below both appear to be pedicle valves. They have thick, ovate shells that are wider than long and feature only a few, strong plications. The surface of the shells also features fine striae (lines that extend from the beak) and concentric growth lines.

Specimen #1 - Pedicle valve
Anterior - you can see some of the striae along a plication near the margin of the shell

Specimen #2 - Pedicle valve with more visible striae in the folds between the plications.
Interior views of the pedicle valve. Some matrix needs to be removed yet. A better view of the internal structures can be seen in the specimens I blogged from the Licking Creek formation of  Virginia.

The Kalkberg formation is lower Devonian in age (Lockhovian to Pragian stage). I collected this specimen from a roadcut near Shoharie, NY.

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