Overview

• Excavations at the Calio site between 2019 and 2022 yielded seven small, sharp-edged stone flakes produced by percussion flaking, including one tool with retouched edges for finer cutting
• Palaeomagnetic analysis of the surrounding sandstone and uranium-electron spin resonance dating of a nearby pig fossil place the artifacts between 1.04 million and 1.48 million years old
• The discovery extends Sulawesi’s known hominin tool record from roughly 194,000 years ago to over one million years, aligning its early occupation timeline with neighboring islands like Flores
• No hominin skeletal remains have been recovered at Calio, leaving the species identity of the tool-makers—potentially Homo erectus or a related archaic human—undetermined
• The findings confirm that early human relatives crossed the Wallace Line’s deep-sea barriers, likely by accidental rafting, and spur further fieldwork to locate biological remains