A new eophrynid trigonotarbid (Arachnida: Trigonotarbida: Eophrynidae) from the Pennsylvanian (Kasimovian) Astrasado Formation of the Kinney Brick Quarry, New Mexico is described. This fossil — the first arachnid to be recorded from the Astrasado Formation — is preserved primarily as a dorsal opisthosoma. Pleophrynus hawesi sp. nov. diagnostically preserves evidence for three pairs of posterior opisthosomal spines rather than the two usually seen in other eophrynids. A comparison of opisthosomal tuberculation patterns among the best known eophrynid species is included. At ca. 304.0–306.5 Ma, our new taxon represents one of the youngest records of Eophrynidae, while the Kinney Brick Quarry is only the twelfth site in North America to yield trigonotarbid arachnids; compared to more than 60 such localities in Europe.