The Antlers Formation is a stratum which ranges from Arkansas through southern Oklahoma into northeastern Texas. The stratum is 150 m thick consisting of silty to sandy mudstone and fine to coarse grained sandstone that is poorly to moderately sorted. The stratum is cemented with clay and calcium carbonate. In places the sandstone may be conglomeratic or ferruginous (rich in iron oxides). Based on correlation with the Trinity Group of Texas, the Antlers Formation is estimated to be late Aptian-early Albian. This age range is supported by the presence of two dinosaurs that are also known from the Cloverly Formation, Deinonychus and Tenontosaurus.

Amphibians

Indeterminate frog remains. Possible indeterminate salamander remains.

Fish

References: Cifelli et al. 1999; Wedel et al. 2000, Kielan-Jarorowska and Cifelli 2001; Nydam and Cifelli 2002.

Cartilaginous fish

Ray-finned fish

Possible indeterminate amid remains. Possible indeterminate lepisosteid remains. Possible indeterminate semionotidae remains.

Mammals

Possible indeterminate deltatheroidan material. Indeterminate multituberculate remains. Indeterminate tribosphenidan remains.

Reptiles

Crurotarsans

Possible indeterminate atoposaurid remains. Possible indeterminate goniopholidid remains. Possible indeterminate pholidosaurid remains.

Lepidosaurs

Possible indeterminate scincid remains.

Ornithischians

Saurischians

Possible indeterminate bird remains are known from the formation.

Turtles