" The chronicles of Australian fauna are amazingly full of stories such as this – of animals that are there one moment and gone the next. A more recent casualty of the phenomenon was a frog called Rheobatrachus silus, which was around for such a short time that it didn’t even manage to attract an informal name. What was extraordinary about R. silus (and it almost goes without saying that there would be something) was that it gave birth to live young through its mouth – something never before seen in nature inside Australia or out. It was discovered by biologists in 1973 and by 1981 it had disappeared. It is listed as ‘probably extinct’. My "

― Bill Bryson , In a Sunburned Country