Large 1.55" Flexicalymene Trilobite From Ohio

This is a very large, 1.55 specimen of Flexicalymene retrorsa from the famous trilobite beds of Mt. Orab, Ohio. It's laid out prone and was prepared using air abrasives under microscope. Comes with the negative impression from when it was found. There is a small brachiopod sitting right on the border of it's head.

There is one spot of shell restoration on the thorax where a repaired crack runs through the trilobite.

About Flexicalymene Trilobites

Flexicalymene is a genus of trilobites of the order Phacopida, suborder Calymenina. These ancient arthropods are an index fossil of the Ordovician, between 488-443 million years ago. The graceful articulation, especially of the thorax segments, demonstrates that this distant precursor of insects is deserving of its delightful name.

Flexicalymene is often found enrolled, seemingly to protect its softer underside from threats on a sea floor teeming with ancient life and increasingly complex predators. Sealing itself inside the hard carapace may be a protective maneuver, or it may simply be the pose of death.

Two species of Flexicalymene are found in the Richmond Formation of Ohio, but in different sub-units. Flexicalymene meeki has small genal spines and is the more common of the two, often coming from Mt Orab, Ohio. These spines are absent in the other species, F. retrorsa. The F. retrorsa cephalon is more rounded, while the F. meeki cephalon is pronounced. They were also denizens at different locales. Calymene, meaning “beautiful crescent”, should not be confused with Flexicalymene: it is a separate genus.

Flexicalymene meeki has been studied for its abundant perforations. The perforations have been interpreted as the loci of sensory hairs: these loci occur in many sizes, and are an interesting feature of exoskeleton microfeatures. They are concentrated on areas most likely to contact other objects in the environment.
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DETAILS
SPECIES
Flexicalymene retrorsa
LOCATION
Mt. Orab, Ohio
FORMATION
Arnheim Formation
SIZE
1.55" long
SUB CATEGORY
ITEM
#17267
GUARANTEE
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