†Gastric-brooding Frog (Rheobatrachus)

There were two species of Rheobatrachus, and they were pretty special. Their name refers to the unique way they incubated their young, different than any other known species of frog. Females swallowed fertilized eggs and once in her stomach acid production would cease, thought due to a chemical contained in the egg jelly. For at least six weeks, the mother ate nothing while the tadpoles developed inside her stomach, which would swell to an enormous size in the body cavity. She vomited them up as fully formed frogs!

They lived in streams and pools, being heavily aquatic. The rarer Northern species, R. vitellinus, occurred in rainforests of the Clarke Range in central eastern Queensland. These frogs were a dark pale brown, with slimy bumpy skin and vivid yellow patches along the underside. R. silus, the Southern frog, was recorded more frequently, living in the Conondale Ranges and Blackall Range in southeast Queensland. It was smaller, more grey in colour, had a cream underside, and dark brown limbs with yellow underneath. R. silus was kept in captivity until the early 1980s, being of great interest to the scientific community. Despite extensive searching none have been seen since 1981. In 1985 chytrid fungus was found in the range of the Northern gastric-brooding frogs, and many dead frogs of other species were observed. It is believed that the spread of chytrid was largely responsible for the extinction of both species.

In 2013, The Lazarus Project was successful in creating a living early-embryo containing DNA of R. Slius. The project hopes to “de-extinct” the Gastric-brooding frog by cloning.