From its foot structure it is thought that Sinodelphys was a tree-dweller , like its non-marsupial contemporary Eomaia and modern opossums such as Didelphis . Luo et al . ( 2003 ) inferred from the foot structure of Sinodelphys that it was a scansorial tree-dweller , like its non-marsupial contemporary Eomaia and modern opossums such as Didelphis .