A new species of chameleon could be the world’s smallest reptile
Scientists have discovered a whole new species of chameleon in a patch of rainforest in northern Madagascar. This so-called nano-chameleon is about the size of a sunflower seed, fits on the tip of a finger, and is possibly the smallest reptile on Earth.
Officially known as Brookesia babe, Where B. nana In short, the new species is so small that it is thought to survive on a diet of mites and springtails, which it stalks in leaf litter.
Finding such a small reptile raises interesting questions about the lower limits of body size in vertebrates. It also highlights the astonishing and very threatened biodiversity of Madagascar. Scientists suspect that the chameleon will soon be listed as Critically Endangered.
Crouched in the grass
Like other chameleons, this tiny reptile has a projectile tongue that it uses to catch its prey. The creatures have found a successful niche in their natural habitat, hunting by day on the rainforest floor and retreating at night to the shelter of blades of grass.
If a larger predator comes calling in the dark, the swaying of the grass stem alerts the chameleon of danger, in which case it just falls into the undergrowth, says Marc Scherz, evolutionary biologist at the University of Potsdam in Germany and co-author of the study.
So far, scientists have only observed two individuals: a male and a female, each captured in 2012 during an expedition to a group of cool, rainy mountains known as the Sorata massif.
Researchers suspect this nano-chameleon holds the title of world’s smallest reptile. Its closest competitor is a creature called Brookesia micra, a tiny species of chameleon that made its debut in 2012, photographed atop a match.
“It’s kinda silly to think to yourself, ‘Oh, that’s a few millimeters smaller than that other thing,'” Scherz says. “But when the millimeters are two or three percent of your body size, that changes a lot. “
“Most scientific work takes place in these small, incremental steps,” Scherz adds.
The fact that only two individuals were found makes it difficult to generalize the results. It is possible that other chameleons of this species are larger or smaller, just as humans can have different heights. This is because scientists already know that chameleons in this family tend to have larger females and smaller males, which is called sexual dimorphism.
It’s also difficult to determine when such a small animal is really an adult, Scherz says. Fortunately, when he subjected the female to a Micro-CT exam, he found traces of eggs in the ovaries. “I ran upstairs and thought, ‘Look, we’ve got the confirmation,’” he recalls.
Determining the age of male chameleons is a bit more difficult and requires careful examination of the genitals of the animals. As young, the genitals of males, called hemipenes, look a bit like smooth balloons, but they become more intricate and ornate as they grow older. Since this male did not have a “smooth ball,” he is probably not a juvenile, Scherz says. The smaller chameleons have relatively large genitals compared to related species which have larger bodies, he adds.
“The female is definitely an adult,” says Tony gamble, an evolutionary biologist who studies dwarf geckos at Marquette University, but was not involved in the study. “And it looks like the male is probably an adult too.”
How far can you go?
Besides its cute side, scientists say the discovery of another small species of chameleon raises all kinds of questions about the limits of smallness in vertebrates.
For example, B. nana is much smaller than smaller birds or mammals, Scherz says, but there are frogs that are even smaller.
At some point, however, you reach a limit for the size of a reptile. Part of it is a surface issue, says Gamble. While it might seem counterintuitive, smaller creatures actually tend to have a higher area-to-volume ratio than larger creatures. And the higher this ratio, the more sensitive an animal will be to water loss.
“There also seems to be a limit as to where you can put whatever you have,” says Gamble. Many small creatures have reduced skull sizes or overlapping bones, and some lose entire structures during evolution.
“It’s like going from a big house to a small apartment without getting rid of anything. This stuff has to go somewhere, ”says Gamble.
B. nana pay attention
Unfortunately, the future of the little chameleon is bleak. The mountain forest where the lizards are found is already severely degraded, says Rakotoarison.
Many people in this region cannot afford rice or meat, Scherz says. Poverty and population growth have led to the clearing of tropical forests to make way for agriculture and livestock; deforestation affects around 94 percent of previously forested land in Madagascar, according to NASA.
With a small home range and threats to its habitat, the new species of chameleon will spearhead critical extinction status through the International Union for the Conservation of Nature, a group of conservation. The good news is that the Sorata massif has recently been included in a new protected area in Madagascar.
“It’s fine to say, ‘Oh, I really hope people stop clearing this forest,’” Scherz says. “But until Madagascar’s economic future changes, there is no hope for its wildlife as people have to eat.”
Meanwhile, Gamble says each new species reminds scientists and the public that Madagascar is a mega-diverse island.
“I think what keeps stories like this front and center in our imaginations is that whenever something like this is discovered it’s like, ‘Oh man I guess [living creatures] can get a little smaller, ”says Gamble.