Zhangheotherium quinquecuspidens (Hu et al. 1997; Earliest Cretaceous, 145-125mya, dentary length 3cm; IVPP V7466) was originally described as a symmetrodont mammal. Hu et al. thought Zhangheotherium radiated before the divergence of living marsupials and placentals. In the large reptile tree Zhangheotherium nests near the base of the pangolin clade between Kopidodon (Eocene) and Manis.
The dentary condylar process curves dorsally and all post-dentary bones are middle ear bones. That dorsal curve removes most of the ability to resist jaw dislocation often caused by struggling large prey and or small pieces of even larger prey are working against large canines, which were also not present in Zhangheotherium. These traits point to a tiny prey diet, likely of insects, just like pangolins. A mobile clavicle–interclavicle allows a wide range of movement, as in bats.
Small patches in the fossil resemble pangolin 'scales' formed of coalesced hair. |