Knightia fish fossil (part and counterpart)
Knightia cf. eocaena • Body fossil, vertebrate
Geological Period
Eocene epoch, Paleogene period
Estimated Age
Approximately 50 million years old
Preservation Type
Carbonization and fine-grained mineral impression/replacement in a split nodule
Condition Assessment
Good, featuring both part and counterpart with clear skeletal articulation, though with minor surface fracturing across the body.
Taxonomic Classification
Phylum Chordata, Class Actinopterygii, Order Clupeiformes, Family Clupeidae, Genus Knightia
Morphological Description
Elongated, laterally compressed body showing distinct vertebral column, fine rayed fins including dorsal, anal, and caudal regions, and delicate scale impressions arranged in rows.
Rock Matrix
Fine-grained calcareous shale / marlstone
Formation & Location
Green River Formation, Wyoming, USA
Size & Dimensions
Approximately 8-10 cm in length, typical for the species
Value & Rarity
Estimated Market Value
$50 - $150 USD
Auction Estimate
$75 - $200 USD
Rarity Assessment
Common, due to the prolific nature of the Green River Formation deposits
Scientific Significance
Provides critical insight into Eocene freshwater lacustrine ecosystems and early teleost fish evolution.
Preparation Recommendations
Keep dry, avoid excessive humidity, store in a stable climate-controlled environment, and display away from direct sunlight.
Notable Features
Complete part and counterpart pairing showing exceptional alignment of the vertebral column and fin rays.