Now it makes sense, the abstract says:
Ediacaran macrofossils are as “strange as life on another planet” and have evaded taxonomic classification, with interpretations ranging from marine animals or giant single-celled protists to terrestrial lichens. Here, we show that lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their phylogeny. Dickinsonia and its relatives solely produced cholesteroids, a hallmark of animals.
They couldn’t tell if it was animal or vegetable. However, this is some poor reporting too. It was cholesterol that was detected, not “fat”, and cholesterol is a hallmark of animals.