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 (268.0 - 265.0 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/M. Clapham] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 40820: authorized by David Bottjer, entered by Matthew Clapham on 01.07.2004