Wednesday, December 14, 2011

Chilotrypa ostiolata from Lockport, NY

One of the most common Bryozoans that I found at the Lockport, NY exposure of Irondequoit limestone Rochester Shale is Chilotrypa ostiolata. The ID is based on specimens displayed at the Primitive Worlds website and the book "The Clinton of Western and Central New York" by Tracy Gillete (1947). Chilotrypa ostiolata is a thin, narrow branching bryozoan. Most pieces I find are loose and broken from the main colony.

This first specimen reminds me of a leg bone from some animal.

Note the structure of the individual zooecia where a single polyp lived. They are shaped kind of like a balcony on the side of a tower so the animal could lean out and spread its lophophore tentacles to catch passing food.

Some more individual pieces.

Here are a couple of slabs of the Irondequoit limestone Rochester Shale that have branches of Chilotrypa ostiolata preserved on them.

Note the Crinoid stem among the debris. The fact that most of the individual pieces of Chilotrypa ostiolata show evidence that there were broken before burial indicates that this is likely a storm deposit or possibly a lag deposit.

The Irondequoit limestone Rochester Shale is Silurian in age (Wenlock series, Sheinwoodian stage).

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