There is more to pumpkin toadlets (Brachycephalus ephippium) than meets the eye – the human eye, at least.
Research into the tiny Brazilian amphibians reveals that they display extraordinary fluorescent patterns on their heads and backs. The patterns are present on bony plates just beneath their skins, and are visible in ultra-violet lights.
Normally, therefore, they are invisible to humans, but that’s OK, because they did not evolve to serve as warnings to large animals.
Rather, says researcher Sandra Goutte from New York University in the US, they are a back-up mate-finding system. Pumpkin toadlets search for partners by making soft buzzing calls, but the bright fluorescence fills the same purpose when surrounding noise is too loud for the calls to be heard.
Goutte and colleagues present their findings in the journal Scientific Reports.