To summarize the new animal size -

Patagomaia chainko is described as medium-sized by today’s standards, around the size of an Andean fox, and the species was estimated to weigh 2-25 kg (4-51 lbs).

It is one of the largest mammals from the Late Cretaceous period, around 70 million years ago. Most mammals during that time were under 100g(.22 lbs), with few reaching 1kg(2.21 lbs).

I expected it to be this large