Age constraints on Pleistocene megafauna at Tight Entrance Cave in southwestern Australia

Abstract

A well-stratified succession of fossiliferous sediments occurs in Tight Entrance Cave, southwestern Australia. These infill deposits contain the remains of megafauna and have accumulated intermittently since the Middle Pleistocene: >137, 137-119 and 50-29 ka, according to the results of14C, U-Th, ESR and OSL dating techniques. Megafaunal species richness was highest in the latest part of the penultimate glacial maximum and during the subsequent last interglacial (137-119 ka), but remains are less abundant following an apparent ∼70 ka depositional hiatus in the sequence. Most megafaunal specimens from the upper (<44 ka) units are fragmentary, and reworking from older strata cannot yet be ruled out. However, one specimen of Simosthenurus occidentalis (a large extinct kangaroo), a pair of articulated dentaries showing no signs of secondary transportation, was found within a sedimentary layer deposited between 48 and 50 ka. This represents one of the youngest demonstrably in situ occurrences of an Australian megafaunal taxon. Crown