Earliest Stone Tools?

Artifacts have been found near Lake Turkana that are reported to be the earliest stone tools yet produced.  Live Science has this:

Until now, the earliest known tools were about 2.8 million years old, the researchers said. The artifacts are by far the oldest handmade stone tools yet discovered — the previous record-holders, known as Oldowan stone tools, were about 2.6 million years old.

"We were not surprised to find stone tools older than 2.6 million years, because paleoanthropologists have been saying for the last decade that they should be out there somewhere," Harmand said. "But we were surprised that the tools we found are so much older than the Oldowan, at 3.3 million years old."

It remains unknown what species made these stone tools. They could have been created by an as-yet-unknown extinct human species, or by Australopithecus, which is currently the leading contender for the ancestor of the human lineage, or by Kenyanthropus, a 3.3-million-year-old skull of which was discovered in 1999 about a half-mile (1 kilometer) from the newfound tools. It remains uncertain exactly how Kenyanthropus relates to either Homo or Australopithecus.

Part of this is because Kenyanthropus is very badly deformed postmortem and it is very hard to figure out its morphology. In recent years, it has not been seriously included in human lineage models.There is evidence at the site of Gona for the use of tools, around 3.3 million years ago, but no actual tools, themselves.  This represents a more concrete example of early tools.  According to the picture, these are very rudimentary choppers.  More pieces of the puzzle.