Docofossor brachydactylus

Docofossor is the oldest subterranean mammaliaform known, as it hails from the middle jurassic Tiaojishan formation roughly 160 million years old.
As it's name implies, it was a fossorial docodont.

It was a heavily built animal with physiological adaptations remarkably similar to modern golden moles, which leads to the conclusion it had a very similar lifestyle.
It is almost as adapted to digging as modern moles, with almost every anatomical aspect devoted to it.
Only the jaws are a bit less specialized.

It was roughly 9 centimeters in length and weighed around 15 grams, making it a small animal even for the formation's standards.
Docofossor teaches us an important lesson: the image of all mesozoic synapsids being ''generic unspecialized tiny shrew'' couldn't be more wrong.
It's close relatives also adapted to a number of niches, including mimics of otters, sugar gliders, oppossums, hyraxes and chipmunks.

References used:
3c1703fe8d.site.internapcdn.ne…

i.ytimg.com/vi/KMPQQb4hXFs/max…

3.bp.blogspot.com/-c_r7QkvVyd0…

en.wikipedia.org/wiki/Docofoss…



NR4 in my Tiaojishan series