Fossilized Fish / Osteichthyes body fossil
Actinopterygii indet. (cf. Knightia or similar primitive teleost/semionotid form) • Body fossil, vertebrate fish preserved as a flattened compression and partial impression in sedimentary matrix
Geological Period
Cretaceous (likely Lower Cretaceous) or Jurassic
Estimated Age
Approx. 100 to 150 million years old
Preservation Type
Carbonization and compression/impression in fine-grained sedimentary rock
Condition Assessment
Fair to Good; the specimen shows clear vertebral structures and myomere patterns, though head and tail regions are somewhat eroded or partially obscured by matrix and previous breakage/repair
Taxonomic Classification
Phylum: Chordata, Subphylum: Vertebrata, Class: Actinopterygii (Ray-finned fish)
Morphological Description
Elongated fusiform body plan showing distinct chevron-shaped myomeres (muscle blocks), a central vertebral column/spine running longitudinally, and dark organic carbonaceous film representing preserved soft tissues and scales.
Rock Matrix
Fine-grained calcareous shale or argillaceous limestone matrix, typical of ancient lacustrine or marine depositional environments
Formation & Location
Green River Formation (Wyoming, USA), Santana Formation (Brazil), or similar Konservat-Lagerstätten deposits globally
Size & Dimensions
Approximately 15-20 cm in length, consistent with small-to-medium-sized fossil fish of the locality
Value & Rarity
Estimated Market Value
$50 - $150 USD
Auction Estimate
$75 - $200 USD
Rarity Assessment
Common
Scientific Significance
Provides valuable data on ancient aquatic ecosystems, soft-tissue preservation via carbonization, and the taphonomic processes of Konservat-Lagerstätten
Preparation Recommendations
Mechanical cleaning using fine pin vices or air abrasive units under magnification to reveal hidden bone or fin structures; stabilize with an appropriate consolidant (e.g., Paraloid B-72) if flaking occurs; store in a stable, low-humidity environment.
Notable Features
Particularly clear V-shaped muscle segmentation (myomeres) running along the flank and a well-defined central vertebral spine axis.