Trilobite Flexicalymene meeki

Anatomy of Flexicalymene

The Anatomy of Flexicalymene meeki

Flexicalymene meeki range in size from less than a millimeter to more than an inch across and several inches long. This is the most common trilobite species to be found whole in Cincinnati. They are most often found enrolled (in a ball) but are sometimes found fully or partially stretched out.

An enrolled Flexicalymene
How Trilobites Enroll

Commonly Found Fragments of Flexicalymene

(Click on a picture to see a closeup.)  

The Glabella The Flexicalymene glabella is the "nose" or "face" of the trilobite. On either side of the glabella are the eyes. A facial suture bisects the eye and separates the glabella from the "free cheeks". The glabella is plentiful and easy to find, distinguished by it's cloverleaf shape.
Internal Glabella This is the interior of the glabella. Frequently, you will find the trilobite "face down" in the rock matrix, exposing the underside of the exoskeleton.
A Free Cheek The "free cheek" of Flexicalymene meeki are the pleural segments of the cephalon 
Free Cheek in Matrix Free cheeks in matrix.
A Pygidium The pygidium (tail).
This is the interior of the pygidium. It is smoother and concave.
The Thorax A fragment of the thorax.
The distinctive three-hump cross-section of the thorax is one of the most common patterns found in the Upper Ordovician rocks of Cincinnati. It is caused by a single segment of the thorax separating during molting.
This is the interior of the thorax. You may often find it in the surface of a rock. 
A Hypostoma The Hypostoma, or "mouth plate" is situated on the underside of the living Flexicalymene. The shape is hard to distinguish. It is a very small bump with a "lip" on one side and a ridge along the other sides.

Here's more information!

See fragments of Flexicalymene Trilobites found on field trips
See pictures of complete Flexicalymene Trilobites

Fragments of other Cincinnati Trilobites
Ceraurus milleranus, Ceraurinus icarus  and Amphilichas shideleri  

Some Other Cincinnati Trilobites
Back to Trilobite Fragments Identifier
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The trilobite anatomy chart was done with a Flexicalymene replica courtesy of Hank and Laura Barton, Dry Dredger members. The Flexicalymene specimens shown are from the collections of the Dry Dredgers, an association of amateur geologists and fossil follectors. The Cincinnati Trilobite Fragment Identifier was written and produced by Bill Heimbrock, Dry Dredgers member. Send Comments to

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