A newly described fossil from Inner Mongolia, named Megacauda sungei, is the largest Jurassic mammaliaform found so far. Preserved in exceptional detail, it shows how the soft palate, a key mammalian innovation, evolved more than 165 million years ago.
The animal is a docodont, a group that evolved before true mammals, the lineage that includes humans, kangaroos, platypuses and echidnas. It sits just outside that lineage, yet it already had a complex soft palate.
That matters because this fossil discovery suggests the feature may have allowed our own ancestors to develop diverse ways of eating and exploit new environments.
A Landscape That Would Barely Seem Familiar
Go back 165 million years and Inner Mongolia looked vastly different from today. Freshwater rivers crossed forests that held some of the earliest redwood trees, and long-snouted pterosaurs soared overhead. Among the ferns, small feathered dinosaurs dashed about, picking off little reptiles and amphibians scuttling through the leaf litter.
Somewhere along one of those riverbanks, there might have been the splash of a tail as an early mammaliaform dived to escape. Picture a cross between a platypus and an otter. The anima...