The transparent glass frog clearly sees the entire inside of the body

Biologists have found two new species of glass frogs with transparent bodies in a valley at the foot of the Andes mountains in Ecuador.

Less than 16km from the Ecuadorian capital Quito, the rugged slopes of the Andes are among the most biologically diverse, but also most vulnerable, tropical regions in the world.

Glass frog Hyalinobatrachium mashpi (left) and Hyalinobatrachium nouns (right).

At the foot of the Andes is a valley. The river that flows through it, known as the Guayllabamba, is at the center of the remarkable story of two newly identified species of glass frogs.

One of them, Hyalinobatrachium mashpi, lives south of the river in the Mashpi and Tayra Reserves, two adjacent private tropical oases measuring 2,510 hectares. The second species, Hyalinobatrachium nouns, lives on the northern slopes of the valley in the Toisan Range, a steep mountain population isolated from the main Andes belt, 20 km from where the first species was found.

Both creatures have a lot in common. They exist at the same altitude, under similar conditions of temperature and humidity. Both measure 1.9 to 2.1 centimeters from snout to cloaca (a standard measure of amphibians' length).

Comparison of the tops of two new species of glass frogs.

Their bodies are also nearly identical to the naked eye, with a green back dotted with black dots arranged around yellow spots, and a completely transparent abdomen, revealing the heart, liver, and digestive system. and egg sacs (in females).

"At first, we thought they were the same species, but when we analyzed the DNA more closely, we were surprised to see a large genetic difference," said lead author of the study Juan Manuel Guayasamin, a biologist. study of evolution at the University of San Francisco de Quito, said.

Currently, only 156 species of glass frogs are known in the world, mainly living in the northern Andes and Central America, with 90% of which have been sequenced. H. mashpi and H. nouns differ genetically by almost 5%, a large gap for such similar amphibians.