A chameleon small enough to sit comfortably on the head of a matchstick has been discovered on a tiny islet in Madagascar.
The new dwarf chameleon, which has been given the scientific name Brookesia micra, grows to a length of less than 30 millimetres from snout to tail and lives only on the islet of Nosy Hara, said a study published in PLoS ONE this week by German and U.S. researchers. That makes it slightly smaller than the 33-millimetre long gecko that is currently recognized as the smallest reptile ever described.
Animal species isolated on islands sometimes become very small – a phenomenon known as island dwarfism. The new study, led by Frank Glaw, a scientist at the Bavarian State Collection of Zoology in Munich, Germany, suggests that B. micra may be extra small due to a "double island effect," since Madagascar is itself an island, and Nosy Hara is an islet off Madagascar.
The paper describes three other new species of related miniature leaf chameleons, all found only in northern Madagascar over a very tiny range. Based on their genetic analysis, they became separated from one another 10 million to 20 million years ago, and have likely been isolated in the same areas where they are currently found since then.