https://multituberculateearth.wordp.....cia-formation/
https://sites.google.com/view/allot.....ucia-formation

The smallest of the Santa Lucia mammals, Sorilestes andina is known primarily from jaw fragments, with a single articulated spine demonstrating it had a long tail much like its larger relative, Sacadelphys. It appears to have been a terrestrial animal, likely occupying a similar niche to that of several Cretaceous leonardids and our timeline's terrestrial opossums and shrew-opossums. Its long tail is muscular but not prehensile, suggesting that it was used to balance while running. It might also have been used in communication, though its unclear if it was a social animal.