This irascible-looking little guy was recently discovered by biologists on the small island of Nosy Hara, in northern Madagascar. Members of this newly discovered species are on average an inch long from snout to tail tip, a remarkably tiny size that puts them among the world’s smallest reptiles. When not turning their baleful glares at the camera, they run around in a landscape of limestone boulders and leaf fragments and at night roost in low-hanging vegetation no more than a couple inches from the ground. Their diminutive size seems to be the evolutionary result of a phenomenon called island dwarfism, by which animals slowly shrink in size, perhaps in response to the limited resources available on an island (though it also goes the other way, a phenomenon called island gigantism, possibly a result of having few predators).
The species’ name, reflecting its tiny-ness, is Brookesia micra.
Some of the weird wildlife on Madagascar—its mammals especially—probably arrived there by rafting from mainland Africa, we reported back in January. But not its blind snakes. According to a study out now in Biology Letters, these funny-looking creatures date back 150 million years to the Gondwana landmass, and have lived on Madagascar since before it broke off from India and drifted away. And, the researchers say, their story of spreading around the world carries many more twists.
Growing to about a foot long, blind snakes act a lot like worms, burrowing under the surface of every continent except Antarctica. Unlike worms, though, blind snakes have backbones and tiny scales [National Geographic]. They earned their moniker by having blurry vision and sensing chemicals through their skin to find their way around. But despite having backbones, there are few blind snakes in the fossil record, making it hard for researchers to study their evolutionary history. So lead researchers Blair Hedges and Nicolas Vidal had to rely on living species. They extracted five nuclear genes, which code for proteins, from 96 different species of worm-like snakes to reconstruct the branching pattern of their evolution, allowing the team to estimate the times of divergence of different lineages using molecular clocks [UPI].
Just how did all the exotic mammals of Madagascar, like its unique collection of lemurs, originally reach the African island? Did they float there from the African mainland, or did nature provide a land bridge? The question has vexed biologists because both explanations have their problems. But a new study in Nature proposes an answer to the main problem posed by the floating-across-the-channel idea, suggesting that it is the most likely explanation.
Because of the narrow range of biology on Madagascar, most biologists favored the floating rafts hypothesis. But there has always been a problem with this notion: the currents swirling in the channel and the surrounding Indian Ocean would make it virtually impossible for a floating Noah’s Ark of vegetation to reach Madagascar’s shores [AFP]. Were those currents always this way, though? No, says a team led by Matthew Huber.