Madagascar island is known for its unusual wildlife, including a newcomer to the scene: the Brookesia nana. This unusual reptile, also known as the nano-chameleon, can fit on the tip of a human finger and they are the smallest known reptile in existence. As of this time, they have only found two nano-chameleons, but interestingly, one is a male and one is a female. They are able to analyze the difference between the sexes and there are some differences to be found.
For example, the female's body is small among chameleons at only 19 mm, or 29 mm, if you decide to include the tail. The male body, on the other hand, is 13.5 mm, or 22 mm with the tail. That makes the male nano-chameleon the smallest reptile in existence.
A study was published in Scientific Reports. The first author of the study, Frank Glaw, had the following to say: "At a body length of just 13.5mm and a total length of just 22mm including the tail, the male Nano-Chameleon is the smallest known male of all higher vertebrates." This new chameleon does have a close relative, the Brookesia micra, although it is only half the size of that lizard that lives in the same mountains. It really goes to show just how miniature these chameleons are, according to Jörn Köhler, co-author of the study.
Scientists from the Bavarian state collection of zoology led the team of international participants. They wanted to make sure that the chameleons were fully grown, so they did CT scans and found that the female had eggs and the male had fully-developed genitalia. That suggests that both of the reptiles are mature. Speaking of the male's genitalia, they were not necessarily miniature when compared to the rest of the body. They were almost 20% of the entire length of the body, and that would be necessary considering the female's larger size so mating is possible. It is something known as the "sexual size dismorphia," as the female is significantly larger.
At this time, it is not known why nano-chameleons are so small, especially when you consider the larger habitat where they live. This was considered by Andolalao Rakotoarison, co-author of the study, who said: "There are numerous extremely miniaturised vertebrates in Madagascar, including the smallest primates and some of the smallest frogs in the world, which have evolved independently."
They went on to talk about how species on small islands tend to get smaller but in this case, it doesn't really make sense. These reptiles live on mainland Madagascar in the mountains, so there is plenty of room for them to grow. Finding these reptiles was good news, but deforestation may be threatening their life and the environment where they live at this time. At this point, the area is designated as a protected space, so hopefully the species will continue to thrive.