Large Flexicalymene Trilobite From Ohio - 1.45"

 
 
This is a large and very inflated Flexicalymene retrorsa trilobite fossil from the famous trilobite beds at Mt. Orab, Ohio. It has been prepared under microscope using air abrasives to bring out all of the detail. This specimen is laid out perfectly prone and in great condition. It's very large for Flexicalymenes from this location, probably in the top 1% size wise. There is about 5% shell restoration on the left hand side of the thorax where a crack ran through the trilobite.

Flexicalymene is a genus of trilobites of the order Phacopida, suborder Calymenina. These ancient arthropods are an index fossil of the Ordovician (488-443 mya). 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.

There are two species of Flexicalymene found in the Richmond Formation but in different sub-units. Flexicalymene meeki have small genal spines and is the more common of the two, often coming from Mt Orab, Ohio. These spines are absent in 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 those areas likely to contact other objects in the environment.
DETAILS
SPECIES
Flexicalymene retrorsa
LOCATION
Mt. Orab, Ohio
FORMATION
Arnheim Formation
SIZE
1.45" long
SUB CATEGORY
ITEM
#10411
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