This is part of a series called “Nova collection of the most curious animals in the world”. There is no information as to why the sloth has a human face. It could be that like many older artists – Tempesta drew an animal he had never seen with his own eyes.
The caption includes two words that I think reference: Asclepius and primate. The first usage of the word primate originates from 1200. I was unable to find the first reference of a sloth being a marsupial versus a primate. Although, I do not think it would be unheard of for sloths to be mislabeled as a primate in the 17th century.
The next question is – How do sloths and the God of Medicine relate? That I have no answer for. And I looked into this way longer than I should have.
Tempesta, Antonio. Sloth, 17th Century. Rijksmuseum, Public Domain License. Information is from Wikipedia(CC BY-SA 3.0).