What is "rugosodon"

Rugosodon is an extinct genus of multituberculate (rodent-like) mammals from eastern China that lived 160 million years ago during the Jurassic period. The discovery of its type species Rugosodon eurasiaticus was reported in the 16 August 2013 issue of Science. The species is the oldest so far described in the multituberculate family, the most successful and long-lasting lineage of all mammals.