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

Arguably the saddest thing from this timeline's Santa Lucia Formation, Potentioperadectes vastata is the closest thing this world has to a marsupial (phylogenetic studies do recover it as a marsupialiform, though sometimes it groups more closely with peradectids than true marsupials) and while this would have been the time and place for their debut in our world, here this poor bastard will leave no descendents. Hell, it isn't even a common fossil find, with only one semi-complete skeleton. It likely lived a lifestyle akin to that of our opossums, and show adaptations to both an arboreal ecology (opposite thumbs) and terrestriality (stronger pelvis). In a place already filled to the brim with opossum-wannabees, this animal is the definition of stunted potential.