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

Sacadelphys is the most locally common genus of leonardid, a lineage of meridiolestidans related to the Late Cretaceous Leonardus and Cronopio (as well as necrolestids, which are highly derived members of this group). Several remnants attributed to therian mammals from the Late Cretaceous of South America seem to actually belong to this group (I can only recommend the book Mesozoic Mammals from South America and Their Forerunners for a complete and in-depth discussion), so it seems likely most if not all Santa Lucia leonardids represent old endemic lineages dating back to the Cretaceous. Sacadelphys seems to form a clade with the smaller Sorilestes andina and other contemporary taxa from Brazil, Pseudodidelphidae, which seems to have taken (or perhaps continued in, since Cretaceous leonardid remains are fragmentary at best so we know little of their post-cranial anatomy) niches occupied in our world by opossums and other metatherians, just to rub it in Potentioperadectes' face even more. Sacadelphys in particular has a muscular, prehensile tail, suggesting arboreal habits for its ten species. Ranging from the Monito del Monte sized S. minor to the spider-monkey sized S. chadi, they all seem to omnivorous, though some species like S. tridentis show speciations towards carnivory like more carnassial-like molars, effectively acting as the mesopredators to Kuzcotherium elegans' apex predator. Some like S. planodens (a rare folivore) seem to have been pretty social, occuring in large numbers, something mirrored by some of our timeline metatherians of the same formation. Some even appear to have pneumatized hyoids similar to those of howler monkeys, suggesting that their troupes fileld the canopies with noise.