Northern Gastric Brooding Frog (Rheobatrachus vitellinus)
Southern Gastric Brooding Frog (Rheobatrachus silus)
The Gastric Brooding Frogs were unique. No other frogs like them are known. Little known or undiscovered until the 1970s and 80s, both species had died off by 1985. These two extinct Australian frogs didn't raise their young in the usual way. While most frogs mate, and then lay their eggs in or near water and allow them to hatch, Gastric Brooding Frog females, as their name suggests, swallowed the fertilised eggs, and allowed them to develop in her stomach. The eggs, and then the tadpoles, lived off of yolk, and both produced a hormone which prevented the mother's stomach from producing digestive acids. During this period, the mother didn't eat, but remained active. Once the babies completed their metaorphosis from tadpole to frog, the mother regurgitated them, and they hopped out of her mouth, fully formed. Unfortunately, not much more is known about them.
So sad to see you go, crazy frogs.