Complex sentence: Originally thought to be Neanderthal, the specimens have since been dated to over 300,000 years ago, making them the oldest known fossil remains of "Homo sapiens" and implying an Africa-wide human presence at a date far earlier than previously thought.
Split into simpler sentences: Originally thought to be Neanderthal, the specimens have since been assigned to "Homo sapiens" and have been dated to over 300,000 years ago. This makes them the oldest known fossil remains of "Homo sapiens" and implies an Africa-wide human presence at a date far earlier than previously thought.