Scaled down… why this tiny lizard is the world’s smallest reptile

The minute lizard — known as Brookesia nana

Credit: Glaw et al, Scientific Reports 2021

Small enough to perch comfortably on a human fingertip, it might be mistaken from a distance for a cricket or a beetle.

But while this insect-sized chameleon may be barely half an inch long, it still holds a record-breaking place in the animal kingdom — as the smallest known reptile on planet earth.

The minute lizard — known as Brookesia nana — was tracked down by a team of naturalists in the northern forests of Madagascar, the Indian Ocean island that lies 250 miles off Africa’s south-east coast.

According to the team’s findings, published in an article in the journal Scientific Reports, it is proof of how animals that evolve in isolated island environments often grow either far smaller or larger than the norm elsewhere.

Madagascar is one of the most biodiverse islands in the world, with most of its abundant wildlife species found nowhere else.

Thanks to both "island dwarfism" and "island gigantism", dog-sized elephants and cat-sized dormice once also roamed islands like Malta and Sicily.

“There are numerous extremely miniaturized vertebrates in Madagascar, including the smallest primates and some of the smallest frogs in the world, which have evolved independently,” said the article’s co-author Andolalao Rakotoarison, of Madagascar’s University of Antananarivo, who collaborated with German scientists for the project.

The tiny chameleon is believed to be the smallest male among almost 11,500 known reptile species, according to Frank Glaw of the Bavarian State Collection of Zoology in Munich, another of the article’s co-authors.

Unlike other larger chameleons, it does not have much capacity to change its colour. However, the male of the species — which is typically only two-thirds the size of the female — does have one distinguishing feature: exceptionally large genitals, which measure nearly 19 per cent of its body size.

These are to compensate for the disparity in size with the female during reproduction, the scientists said.