a, Digital elevation model of southwest Sulawesi. 1: Talepu; 2: Maros karst area. Area enclosed by rectangle shown in d; map data: copyright USGS/NASA SRTM (2007). b, Geological map of southwest Sulawesi (data from refs 11, 63, 64). The Walanae Depression (WD) is an elongate fault-bounded basin (also known as the West Sengkang Basin) separated from the Bone Mountains to the east by a major fault, the East Walanae fault (EWF), which formed in response to east–west compression and strike-slip movements along the Walanae fault zone. To the west the basin is bordered by the Western Dividing Range, consisting of uplifted Miocene volcanics deposited in a shallow marine environment13. The Walanae Depression basin infill consists of a several-kilometre-thick regressive sequence, named the Walanae Formation. In the southern part of the Walanae Depression, the Walanae Formation is folded and deformed by Pleistocene compression, whereas to the north near Lake Tempe deposition continues to the present day. 1: Talepu; 2: Paroto (alluvial terrace of the Walanae River); 3: Beru8; 4: Tanrung River (palaeontological site: coastal terrace deposits11); 5: Sompe8,9,10; 6: Celeko8,9,10; 7: Maros karst archaeological sites5. c, Schematic stratigraphic scheme for the northern Sengkang Basin at the latitude of the Talepu site (green dotted line in b). The Walanae Formation basin fill represents a regressive sequence that was strongly influenced by tectonic movements along the Walanae fault zone. The youngest unit of the Walanae Formation is the Beru member (deltaic sands, clays and gravels), which contains fossil vertebrate remains of the Walanae Fauna11. The lower part of the Beru member (unit A) is characterized by sedimentary structures indicative of shallow marine/estuarine/fluvial depositional environments. The upper part of the Beru member (unit B) consists of fully terrestrial fluvio-lacustrine deposits, which merge into the modern floodplain along the depocentral axis of the Walanae Depression. The coarser-grained unit B of the Beru member was not deposited in the Sengkang anticline, which started to rise during the Middle Pleistocene, or in the southern portion of the Walanae Depression south of Talepu. East of the Walanae fault Zone, in the East Sengkang Basin, uplift and folding during the Pliocene caused a depositional hiatus. Here Late Miocene deformed marine deposits of the Walanae Formation are unconformably overlaid by a conglomerate up to 5 m thick, the Tanrung Formation, which contains a distinct fossil vertebrate fauna11. During the Middle and Late Pleistocene, uplift of the Western Dividing Range generated the formation of alluvial fans and influxes of coarse-grained boulder conglomerates into the Walanae Depression. d, Geological map of Talepu area with sub-horizontal layering, fault-bounded to the east by steeply west-dipping strata of the Sengkang anticline. 1: Modern alluvium; 2: Late Pleistocene alluvial terrace; 3–7: lithological sub-units of the Walanae Formation: 3: fluvio-lacustrine facies of the upper part of the Beru member; 4: fluvio-estuarine facies of the lower part of the Beru member; 5: shallow marine facies of the Samaoling member; 6: deep marine facies of the Burecing member; 7: coral reef facies of the Tacipi member; 8: strike and dip; 9: sub-horizontal layering; 10: major fault; 11: sites with surface-collected stone artefacts; 12: sites with in situ stone artefacts; 13: fossil vertebrate localities.