[3] C. grandisonae (common name: Puerto Eden frog) is endemic to Patagonia, including both Chile and Argentina.

It inhabits rainforest and wetlands of the southern fjordlands and Andes in Patagonia.

[2] Small to medium-sized frogs, C. grandisonae adults reach a snout–vent length of about 46 mm (1.8 in), with typical frog-like appearance and body proportions.

Back of the body and limbs are rather uniformly bright green with brown to reddish warts.

Eggs are deposited in October (middle austral spring), and development to metamorphosis takes about 10–12 weeks, to December (early summer).