Flexicalymene Trilobite
Flexicalymene cf. meeki • Body fossil; Invertebrate Arthropod
Geological Period
Upper Ordovician
Estimated Age
440 to 450 million years
Preservation Type
Replacement and recrystallization; Calcified exoskeleton in a sedimentary matrix
Condition Assessment
Fair to Good; the specimen is partially complete but shows significant erosion or incomplete preparation on the outer lobes and cephalon edges
Taxonomic Classification
Phylum Arthropoda, Class Trilobita, Order Phacopida, Family Calymenidae, Genus Flexicalymene
Morphological Description
Specimen shows a distinct three-lobed body structure with a rounded glabella, deep axial furrows, and thoracic segments. The specimen appears partially enrolled, displaying the typical shovel-shaped cephalon. Visible pleural ribs and an axial lobe are present.
Rock Matrix
Grey to tan limestone/marl matrix typical of the Cincinnatian series
Formation & Location
Commonly found in the Waynesville Formation or Liberty Formation of the Cincinnati Arch (Ohio, Kentucky, Indiana, USA) or Morocco
Size & Dimensions
Approximately 3 to 5 cm in length; typical for adult Flexicalymene specimens
Value & Rarity
Estimated Market Value
$15 - $40 USD
Auction Estimate
$20 - $50 USD
Rarity Assessment
Common; Flexicalymene is one of the most prolific trilobite genera found in Paleozoic strata
Scientific Significance
Excellent indicator of Ordovician marine environments; provides data on the 'Great Ordovician Biodiversification Event' and early arthropod morphology
Preparation Recommendations
Minimal mechanical cleaning with an air scribe or micro-blaster; store in a low-humidity environment to prevent pyrite disease if metallic inclusions are present
Notable Features
The specimen exhibits defensive enrollment behavior, a common survival trait in trilobites to protect their vulnerable soft ventral side from predators