Glaw, a reptile expert at the Bavarian State Collection of Zoology in Munich, said the tiny male and a slightly larger female were spotted on a mountainside by a local guide during a 2012 expedition.

“You really have to get down on your knees to find them,” Glaw he said on Saturday AEDT. “They are obviously camouflaged and they move very slowly.”

Glaw and his colleagues performed a CT scan of the female and discovered that it harboured two eggs, confirming that it was an adult.

For the male, the researchers took a close look at its “well-developed” genitals, which in chameleons come in pairs known as hemipenes.

They found that the genitals of the Brookesia nana specimen were almost one-fifth of its body size, possibly to allow it to mate with the larger female.

“I have few doubts it’s an adult male,” Glaw said. “If we had a pair mating it would obviously be better proof.”

Confirming Brookesia nana as the smallest reptile species will require finding more of them, which might take several years, he said.

The team’s research was recently published in the journal Scientific Reports.

Chameleons are threatened by deforestation on Madagascar, which is home to numerous species.

AP