Large, 1.4" Flexicalymene Trilobite - Ohio

 
 
This is a nice, 1.4" long Flexicalymene retrorsa trilobite fossil from the famous trilobite beds at Mt. Orab, Ohio. It was cleaned using air abrasives under microscope. At nearly 1 1/2" this is a large trilobite from the locality and it's inflated with good shell quality.

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
1.4" long
CATEGORY
SUB CATEGORY
ITEM
#55417
GUARANTEE
We guarantee the authenticity of all of our
specimens. Read more about our
Authenticity Guarantee.