Tetrapod Footprint or Trackway
Chirotherium cf. barthii or similar pseudosuchian tracks • Ichnofossil (Trace Fossil); vertebrate footprint
Geological Period
Triassic (Early to Middle Triassic)
Estimated Age
240 to 250 million years
Preservation Type
Epichnial mold/concave impression; mechanical indentation in terrestrial sediment
Condition Assessment
Fair to Good; the impression is worn and the matrix exhibits some weathering and fractures. Anatomical definition is soft.
Taxonomic Classification
Ichnogenus: Chirotherium (cf.); Ichnofamily: Chirotheriidae
Morphological Description
The specimen shows deep impressions suggestive of a pentadactyl (five-digited) foot. Visible features include a distinct indentation for a divergent fifth digit (the 'thumb-like' projection characteristic of Chirotherium) and semi-parallel tracks of the median digits. The surface lacks fine cutaneous detail (skin texture) but shows significant depth and pressure displacement.
Rock Matrix
Red Bed Sandstone/Siltstone; rich in iron oxides (hematite) giving the characteristic reddish-brown hue
Formation & Location
Moenkopi Formation (Southwest USA: Arizona, Utah) or the Buntsandstein (Germany/UK)
Size & Dimensions
Approximately 10 to 15 cm in length; consistent with a medium-sized archosauriform or early crocodile-line archosaur
Value & Rarity
Estimated Market Value
$150 - $350 USD
Auction Estimate
$200 - $400 USD
Rarity Assessment
Uncommon; while red-bed footprints are found in specific localities, clear identifiable tracks on portable matrix are collectible and less frequent than fragmentary tracks.
Scientific Significance
Trace fossils provide evidence of behavior, locomotion, and habitat preferences that body fossils cannot. Chirotherium tracks are vital for understanding the dominance of pseudosuchian archosaurs before the rise of dinosaurs.
Preparation Recommendations
Keep in a dry environment to prevent further oxidation or flaking of the iron-rich sandstone. Use a soft brush for cleaning; avoid water as it may penetrate micro-cracks in the matrix. Could be consolidated with a reversible polymer like Paraloid B-72 if flaking occurs.
Notable Features
The specimen exhibits the classic 'hand-like' appearance that led early observers to believe these were primate-like tracks before they were identified as pseudosuchian archosaurs. The deep relief suggests moist, pliable sediment at the time of the impression.