Snakes
Boavus idelmani
A small fossil boa — snakes are uncommon finds in the Fossil Butte Member.
Lizards
Saniwa ensidens
The largest lizard from the FBM — a monitor with a long neck, powerful limbs, and a long balancing tail.
Lizards
Bahndwivici ammoskius
A crocodile lizard skeletally indistinguishable from the living Chinese Shinisaurus crocodilurus.
Lizards
Afairiguana avius
An early iguana from Fossil Lake — one of three lizard species identified from the FBM.
Crocodilians
Borealosuchus wilsoni
A primitive crocodilian — neither true crocodile nor alligator — that could reach about 16 feet.
Crocodilians
Tsoabichi greenriverensis
An early caiman from the Alligatoridae lineage — related to living Central and South American caimans.
Baenidae Turtles
Chisternon undatum
A bottom-walking aquatic turtle with a long tail and a head that could not retract into the shell.
Soft-Shell Turtles
Axestemys sp.
A soft-shell turtle — likely an apex or near-apex predator of Fossil Lake.
Soft-Shell Turtles
Plastomenus thomasii
One of three soft-shell turtle species identified from the Fossil Butte Member.
River Turtles
Baptemys wyomingensis
An uncommon river turtle — nearly identical to the living Central American Dermatemys mawii.
Pond Turtles
Echmatemys wyomingensis
A pond turtle that may have spent much of its time basking, like a modern painted turtle.