The journal Nature, dated 14 March 2017, has an article entitled Fossil algae hold clues to origin of modern photosynthesis reporting on a newly discovered set of 'eukaryotic' specimens which may help to identify the origin of photosynthesis in eukaryotes.
However, there is some uncertainty in this.
It can be difficult to pinpoint exactly where ancient fossils lie on the tree of life because, billions of years ago, many organisms were superficially similar. “That’s the problem with this field,” says [Nicholas Butterfield, a palaeobiologist at the University of Cambridge, UK]. “You stand back and squint, and say ‘well, the fossil kind of looks like X.’”
[Stefan Bengtson, a palaeobiologist at the Swedish Museum of Natural History in Stockholm] acknowledges that it’s difficult to peg his fossils’ exact place. “We can never prove their affinity with 100% certainty,” he says. “But we are very confident we have made the best guess.”
The fossils are described in more detail in a study published on 14 March 2017 in PLoS Biology for those who are interested.