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Iuri Ribeiro Dias / UESCFlea toad: fits on the tip of a person’s little fingerIuri Ribeiro Dias / UESC
The male Brazilian flea toad (Brachycephalus pulex) is the smallest known vertebrate in the world, measuring 6.45 millimeters (mm) in length. The animal, first discovered in the Serra Bonita reserve, southern Bahia, in 2011, fits comfortably on the tip of a person’s little finger. Now, a comparison with 46 other adults of the species performed by herpetologist Mirco Solé and colleagues from the State University of Santa Cruz in Ilhéus has reinforced the findings, showing that males average 7 mm in length and females 8 mm, as described in the journal Zoologica Scripta in February. The toad’s tiny feet have just two toes instead of the usual five, a result of the small size that has also been observed in other amphibians. It does not seem to cause a problem as they hop across the forest floor, but a 2021 study showed that they tend to lose their balance when in the air. Solé suggests that for an even smaller vertebrate to exist, other adaptations would be necessary. It seems increasingly difficult to break miniaturization records without losing crucial body parts (Science News, February 27).
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