Rheobatrachus silus was described in 1973 from Queensland streams. The female swallowed fertilised eggs, and the larvae developed in her stomach for around six to seven weeks. During brooding she did not feed, and the stomach ceased secreting hydrochloric acid, so the young were not digested. The jelly around the eggs and secretions from the larvae contained prostaglandin E2, which appears to be the signal that suppresses acid production.
The stomach distended so far that the lungs were compressed and the female relied largely on gas exchange through the skin. She eventually gave birth by opening her mouth and releasing fully formed froglets over a period of days.
The biomedical interest was immediate, and the loss was faster. R. silus was last recorded in the wild in 1981 and in captivity in 1983. The northern gastric-brooding frog, Rheobatrachus vitellinus, was described in 1984 and last seen in 1985. Chytrid fungus is the leading explanation for the collapse. Attempts to revive the lineage from frozen tissue, under the Lazarus Project, have produced early embryos but no living frog.