Petrified Fish Skeleton (Fragmentary)
cf. Diplomystus sp. or Knightia sp. (affinity based on common lacustrine deposits) • Body fossil, vertebrate, mineralized skeletal remains
Geological Period
Cretaceous (likely Lower Cretaceous)
Estimated Age
100-125 million years
Preservation Type
Permineralization and replacement by chalcedony or calcite, showing high detail in skeletal articulation despite fragmentation.
Condition Assessment
Fair to Good; the specimen is a partial section of the post-cranial skeleton, missing the skull and distal fins, but showing excellent articulation of the preserved segment.
Taxonomic Classification
Phylum: Chordata, Class: Actinopterygii (Ray-finned fish), Order: Ellimmichthyiformes (tentative)
Morphological Description
Specimen exhibits elongated, articulated vertebral column fragments with identifiable neural and haemal spines. Visible fine rib structures and remnants of the caudal peduncle area. The surface shows a waxy, semi-translucent luster typical of high-silica replacement.
Rock Matrix
Light gray to tan fine-grained limestone or calcarenite, typical of lithographic limestone deposits.
Formation & Location
Commonly associated with the Santana Formation (Brazil) or the Green River Formation (USA), though the mineralized luster suggests a Brazilian origin.
Size & Dimensions
Approximately 12-15 cm in length; consistent with a sub-adult or small adult specimen of common cretaceous freshwater fish.
Value & Rarity
Estimated Market Value
$40 - $85 USD
Auction Estimate
$50 - $100 USD
Rarity Assessment
Common; while articulated, these specific taxa are found in high abundance in concentrated fossil beds (Lagerstätten).
Scientific Significance
Provides data on the osteology of Mesozoic teleosts and the paleoenvironment of ancient lake systems. The high degree of mineralization suggests rapid burial in anoxic conditions.
Preparation Recommendations
Requires minimal stabilization; keep away from acidic cleaners. Display in a padded case or on a custom stand to prevent abrasion of the delicate mineralized edges.
Notable Features
Striking vitreous luster due to unique mineral replacement; the specimen appears almost 'ghost-like' and translucent under direct light, high-intensity light.