Maiopatagium furculiferum (Luo et al. 2017; Meng et al. 2017; Late Jurassic (Callovian); 160 mya) was originally described as a pre-mammal haramiyid close to Sinoconodon. Here it nests with the large Palaeocene squirrel,Paramys.

The mandible is not known. The subtemporal tuberosity is the dorsal part of the infraorbital foramen. The clavicle is robust here and fused with the interclavicle. The procoracoid and coracoid are poorly ossified and may be atavisms. Perhaps similarly, the tarsus appears to have more bones than typical for mammals, including a medial disc otherwise found in Coendou, the porcupine. The present reconstruction (color) differs from the original interpretation and is more similar to the porcupine.

A patagium has been described, but I have not seen it. Rather a halo of thick straight hair is preserved, similar to the related chinchilla, Chinchilla.