Final answer:
Homo habilis was contemporary with australopiths and had a much larger brain, approximately 800 cubic centimeters. This early human species also made stone tools and consumed a varied diet.
Step-by-step explanation:
The species that may have been contemporaneous with australopiths but had a significantly larger brain were members of the genus Homo, specifically Homo habilis. Homo habilis lived around the same time as later australopiths but had a brain volume of approximately 800 cubic centimeters, which is much larger than that of Australopithecus species. Homo habilis also engaged in tool-making and had a mixed diet of plant and animal food, which is indicative of advanced cognitive capabilities associated with increased brain size.