Two Medicine pterosaur (Cretaceous of the United States)

Where: Teton County, Montana (47.8° N, 112.2° W: paleocoordinates 55.3° N, 77.8° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Two Medicine Formation (Montana Group), Campanian (83.6 - 72.1 Ma)

• horizon is approx. 300 m below the top of the Two Medicine Formation where it underlies the Horsetheif Sandstone, and is therefore considered equivalent to the lower Judith River Formation (lower Upper Campanian, about 77-78 mybp)

• bed-level stratigraphic resolution

Environment/lithology: lacustrine - large; stromatolitic, shelly/skeletal, argillaceous, sandy limestone

• It is inferred that the region at the time of deposition was part of a "proxial lowland" about 700 km from the mid-continental seaway
• well laminated freshwater limestone containing alternating beds of sandstone and mudstone, suggesting a lacustrine environment. The bones were associated with stromatolites and the freshwater pelecypod Unio.

Size class: macrofossils

Preservation: mold/impression, permineralized, replaced with other

Collection methods: quarrying, mechanical,

Primary reference: K. Padian. 1984. A large pterodactyloid pterosaur from the Two Medicine Formation (Campanian) of Montana. Journal of Vertebrate Paleontology 4(4):516-524 [J. Alroy/E. Leckey/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 36934: authorized by John Alroy, entered by Erin Leckey on 19.02.2004, edited by Richard Butler

Creative Commons license: CC BY (attribution)

Taxonomic list

 Unionida - Unionidae
Unio sp. Philipsson 1788 freshwater mussel
 Pterosauria - Azhdarchidae
Azhdarchidae indet. Nessov 1984 pterosaur
PU 22446, left scapula, distal left humerus, distal left radius, carpal and bone fragments