Repenomamus

Repenomamus is the largest known mammal from the Cretaceous period. Its fossil was found in Manchuria.
There is good evidence that it fed on dinosaurs. It is not known whether "Repenomamus" was a hunter or a scavenger.
Life style.
"Repenomamus" was carnivorous. A specimen of "R. robustus" has been discovered with the fragmentary skeleton of a juvenile "Psittacosaurus" preserved in its stomach. 
This is the strongest evidence that Mesozoic mammals fed on dinosaurs, though there were earlier indications of this.
The larger species, "R. giganticus", is the largest mammal known from the Cretaceous. "R. giganticus" was more than 1 metre (39 inches) long and weighed about 12–14 kg (26–31 lb). Its skull measures 16 cm (6.25 in) long, its body 52 cm (20.5 in), and the preserved part of its tail 36 cm (14 in). 
Discovery.
The fossils were recovered from the lagerstätte of the Yixian Formation in the Liaoning Province of China, renowned for its extraordinarily well-preserved fossils of feathered dinosaurs. They have been dated to 130 million years ago, during the Lower Cretaceous period.
"Repenomamus" is a genus of triconodonts, a group of mammaliaformes with no modern relatives.