Tiny chameleon with large genitalia may be the world's smallest reptile
A scientist calls it "a spectacular case of extreme miniaturization."
Brookesia nana is a chameleon so tiny, it can perch on a fingertip with plenty of room to spare. It may be the smallest reptile in the world, according to a team of scientists who described the diminutive animal, which lives in a rainforest in Madagascar.
A male Brookesia nana measured in at half an inch (13.5 millimeters) in length. A female clocked in at a rather larger three-quarters of an inch (19.2 millimeters). Length is measured from the snout to the vent (the under-tail slit).
Herpetologist Mark Scherz, co-author of a paper on the reptile published last week in Scientific Reports, described the chameleon in a blog post as "a spectacular case of extreme miniaturization."
Scherz highlighted the male reptile's "quite large genitalia," a feature that led the researchers to compare genital size with body size in chameleons. The scientists found "the smallest species often have the proportionally largest genital sizes."
The Brookesia nana male chameleon specimen had very large genitals for its small size.
There could be a very practical explanation for the reptile's relative endowment. "We think that this might also be related to size dimorphism: If the female remains larger than the male, a constraint is placed on the reduction of the male genital size," Sherz wrote.
A fair amount of mystery still surrounds Brookesia nana. Researchers hope to learn more about the reptile's mating behaviors as they seek to understand its physical features.
The tiny reptile may seem unreal, especially when you see it sitting on a human index finger for scale. Scherz was amused to see debunking site Snopes had weighed in to confirm its existence.
Some amusing lunchtime reading: a @snopes article on the #nanochameleon, Brookesia nana, because… apparently there was doubt.https://t.co/4WPtOuKKua
— Dr Mark D. Scherz (@MarkScherz) February 1, 2021
Brookesia nana has been described based on just two specimens from a single location, making it an extremely rare and possibly threatened animal. The research team has suggested it be listed as critically endangered due to loss of habitat from human activity in Madagascar.
It's a pressing matter. The scientists wrote in the paper, "We recommend that the extinction risk of this species be assessed officially for the IUCN Red List of Threatened Species as soon as possible."