Phacops Trilobite
Phacops cf. rana • Body fossil, invertebrate arthropod
Geological Period
Devonian
Estimated Age
393 to 419 million years
Preservation Type
Three-dimensional relief preservation, likely mineralized exoskeleton embedded in rock matrix with dark blackish/grey coloration.
Condition Assessment
Very Good to Excellent. The specimen is largely complete, fully articulated in high relief, though minor preparation marks or stabilization may be present around the edges.
Taxonomic Classification
Phylum Arthropoda, Class Trilobita, Order Phacopida, Family Phacopidae, Genus Phacops
Morphological Description
Well-defined tripartite body (cephalon, thorax, pygidium). The cephalon features prominent, bulbous glabella with distinct tuberculate or granular ornamentation and large, highly defined schizochroal eyes. The thorax consists of multiple articulated segments with clear axial and pleural lobes. The pygidium is relatively small and rounded compared to the cephalon.
Rock Matrix
Dark grey shale or fine-grained argillaceous limestone matrix characteristic of classic Devonian trilobite deposits.
Formation & Location
Commonly found in the Atlas Mountains of Morocco (Oufreten/Alnif regions) and the Hamilton Group of North America.
Size & Dimensions
Approximately 5 to 7 cm in length, which is a standard adult size for this particular genus, shown next to a 2 euro coin for scale.
Value & Rarity
Estimated Market Value
$100 - $300 USD
Auction Estimate
$150 - $250 USD
Rarity Assessment
Common, widely available in the commercial fossil market due to extensive commercial quarrying in Morocco.
Scientific Significance
Important for understanding Paleozoic marine ecosystems and arthropod evolution, particularly the advanced visual systems represented by the schizochroal eyes of Phacopida.
Preparation Recommendations
Air abrasive cleaning and pneumatic micro-chisel work under magnification. Store in a stable, dry environment away from extreme humidity fluctuations to prevent matrix cracking.
Notable Features
Exceptionally clear schizochroal compound eye structure visible on the right (and partially left) side of the cephalon, and prominent granular texturing across the glabella.