Hadrosaur Phalanx (Toe Bone)
aff. Edmontosaurus annectens or cf. Maiasaura sp. • Vertebrate body fossil (Dinosaur limb element)
Geological Period
Late Cretaceous (Maastrichtian or Campanian)
Estimated Age
66 - 75 million years
Preservation Type
Permineralization (Silicification/Mineral replacement of bone tissue)
Condition Assessment
Good to Very Good. The specimen is largely complete but shows typical weathering and erosion on the articular ends and some surface exfoliation.
Taxonomic Classification
Chordata, Reptilia, Dinosauria, Ornithischia, Hadrosauridae
Morphological Description
Short, robust cylindrical bone with concave articular surfaces. Exhibits characteristic porous trabecular structure at the proximal end and a constricted waist (diaphysis). Features a distinctive dorsolateral process typical of pedal phalanges in ornithischian dinosaurs.
Rock Matrix
Sandstone/Mudstone matrix remnant (largely removed during preparation). The bone shows evidence of iron-rich mineral staining giving it a brown patina.
Formation & Location
Hell Creek Formation (USA) or Judith River Formation (USA/Canada)
Size & Dimensions
Approximately 5-8 cm in length; consistent with an intermediate phalanx from a sub-adult or adult large-bodied duck-billed dinosaur.
Value & Rarity
Estimated Market Value
$150 - $450 USD
Auction Estimate
$200 - $500 USD
Rarity Assessment
Uncommon; while Hadrosaur material is relatively plentiful in specific North American lagerstätten, well-preserved isolated phalanges are desirable for collectors.
Scientific Significance
Provides data on the locomotion, weight distribution, and ontogeny of Hadrosaurids. Contributes to understanding the biodiversity of late Cretaceous mega-herbivore populations.
Preparation Recommendations
Consolidation with a reversible polymer like Paraloid B-72 to prevent further crumbling. Keep in a humidity-controlled environment to avoid pyrite decay or salt expansion.
Notable Features
Excellent preservation of the cortical bone texture and visible nutrient foramina. The distal end shows some signs of natural taphonomic wear prior to fossilization.