Where: Sonora, Mexico (30.8° N, 112.6° W: paleocoordinates 11.7° N, 40.3° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Antimonio Formation, Wordian (266.9 - 264.3 Ma)

• "Monos Beds"; Composita zone is second-highest in succession

Environment/lithology: marine; shelly/skeletal, cherty/siliceous limestone

Size class: macrofossils

Preservation: replaced with silica

Primary reference: G. A. Cooper, C. O. Dunbar, H. Duncan, A. K. Miller, and J. B. Knight. 1953. Permian fauna at El Antimonio, western Sonora, Mexico. Smithsonian Miscellaneous Collections 119(2):1-111 [D. Bottjer/M. Clapham/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 40811: authorized by David Bottjer, entered by Matthew Clapham on 01.07.2004

Creative Commons license: CC BY (attribution)