SIVIERO, REGA, NICK, & CHADWICK, 2026, SIVIERO, REGA, McLAIN, BRAND, NELSEN & CHADWICK, 2026

Locality: Hanson Research Station (HRS), Niobrara County, Northeastern Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

Bonebeds with 3013 specimens, 96 with macroscopic bone abnormalities and 55 with pathologies attributed to physical trauma.

Pre-Mortem Trauma:

HRS07948: Neural spine from a middle-distal caudal vertebra.

HRS02082: Neural spine from a middle caudal vertebra.

HRS00428: Middle-distal caudal vertebra.

HRS01106: Neural spine from a middle-distal caudal vertebra.

HRS00428: Distal caudal vertebra.

HRS00323, HRS05801, HRS00444, HRS07245: Distal caudal vertebrae.

HRS01295: Distal fragment of neural spine.

HRS000404: Neural spine from a distal caudal vertebra.

HRS01248: Neural spine fragment from a middle-distal caudal neural spine.

HRS14435: Middle caudal vertebra.

HRS00836: Middle caudal vertebra.

HRS00853: Chevron fragment.

HRS17086: Chevron fragment with the bifurcated end mostly complete.

HRS07257: Phalanx of the manus with apparent bone remodeling.

Pseudopathology.

HRS03161: Rib fragment. With root tracies.

HRS02038: Rib fragment.

HRS10676: Cervical vertebra. Postmortem depressions.

HRS12360: Metatarsal. Postmortem depressions.

HRS14005: Distal caudal. Postmortem textural changes on distal joint surface and depressions.

HRS12443: Ischium. Postmortem modified surface texture.

HRS12244: Astragalus. Insect borings.

HRS09967: Pedal phalanx. Insect borings.

Toothmarks via Tyrannosaurus rex (Linichnus serratus, Knethichnus parallelum)

HRS01295: Tooth marks on a neural spine fragment. (Knethichnus parallelum)

HRS09830: Nerual spine with tooth marks. (Linichnus serratus)

HRS03650: Neural spine fragment with tooth marks. (Linichnus serratus)

HRS00428: Caudal vertebra with tooth marks on neural spine. (Linichnus serratus)

HRS00473: Distal caudal vertebra with tooth marks on the centrum. (Linichnus serratus)

HRS09477: Rib fragment with tooth marks.

HRS13582: Radius with several tooth marks. (Knethichnus parallelum)

HRS10076: Ulna with tooth marks.

HRS03887: Rib with tooth marks. (Knethichnus parallelum)

HRS054899: Suragular with tooth marks from a crocodile?

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= Edmontosaurus annectens WYENBERG-HENZLER & SCANNELLA, 2024, 2026 (Note: Maybe a different genus than Anatosaurus).

Locality: MOR locality no. HC-387, Dawson County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Nearly complete skull.

Note: With an embedded Tyrannosaurus rex tooth in the nasal.