Microdocodon

It is unique for preserving the hyoid bone, which is almost unknown in the early mammal fossil record.

The species is notable for providing insight into the evolution of the ability to chew and suckle in early relatives of mammals, by preserving a nearly intact hyoid in the throat.

The complexity of the structure in Microdocodon suggests that chewing and suckle evolved before in the precursors to Mammalia, the mammaliaforms, but after their split with the earlier cynodonts.

[1] Microdocodon is an especially small early mammal, thought to have been a shrew-like insectivore weighing about 9 grams.

Microdocodon lived at the same time as semiaquatic Castorocauda, the subterranean mammaliaform Docofossor, and the arboreal Agilodocodon, all known from the Yanliao Biota.