Isthmian Alligator Lizard

G. rhombifer is a broad-headed, long-bodied lizard, which is similar to Diploglossus monotropis. An adult measures from 35–50 centimetres (14–20 in) in total length, with the tail making up approximately two-thirds of the total length. The upper surface of the body is tan in color with black-edged brown crossbands, and does not have either orange or red markings. C. rhombifer is short-limbed, and has movable eyelids. A well-defined lateral fold, covering small scales, separates the ridges and rows of scales on the belly. The only other species of lizards in Costa Rica that also have lateral folds are of the genus Mesapis. The isthmian alligator lizard is viviparous, meaning that as with mammals, the females bear live young.

The isthmian alligator lizard lives in the lowland rainforests of Costa Rica, and in western Panama. G. rhombifer can mostly be found on land, but has also been found living in trees.