World's Smallest Frog (and Vertebrate)
Paedophryne amauensis was discovered in 2009 by a research team from Louisiana State University, this wee beastie holds the title of the world's smallest vertebrate at 7.7mm in length.
The previous champion was a fish called Paedocypris progenetica, meassured 7.9mm in length.
Hailing from the undergrowth of Papua New Guinea's rain forests, they live a crepuscular lifestyle – coming out at dawn n' dusk to call (presumably to find other smol frog hotties), with a series of high-pitched notes said to resemble that of an insect. In fact, this is how they were discovered – boffins took recordings of evening frog calls and noticed one they couldn't quite identify.
By scooping up and closely examining bits o' leaf matter from where they thought the noise was coming from, they managed to spot a wee frog or two crawling about.
What's very interesting is that they emerge as a smaller adult instead of having to develop from a tadpole.
Most amphibians have a typical three stage life cycle – eggs, then aquatic tadpole-ey things with gills, then mature adults without gills – there are plenty of notable exceptions. Turns out most super miniature frogs, like Paedophryne amauensis, ditch the tadpole stage altogether, with their eggs hatching directly into even teenier versions of the adults.