Gerrhonotus rhombifer had not been seen for fifty years, prior to being rediscovered in 2000 near Golfito,[3] and is one of the rarest species of lizard in Costa Rica.

The upper surface of the body is tan in color with black-edged brown crossbands, and does not have either orange or red markings.

[6] The only other species of lizards in Costa Rica that also have lateral folds are of the genus Mesapis.

[5] The isthmian alligator lizard is viviparous,[6] meaning that as with mammals, the females bear live young.

[7] The isthmian alligator lizard lives in the lowland rainforests of Costa Rica,[5] and in western Panama.