Modern human teeth unearthed from below the ∼128,000-year-old level at Punung, Java: A case highlighting the problem of recent intrusion in cave sediments.

The emergence of modern humans in the eastern edge of the Eurasian Continent is debated between two major models: early (∼130-70 ka) and late (∼50 ka) dispersal models. The former view is grounded mainly on the claims that several cave sites in Southeast Asia and southern China yielded modern human fossils of those early ages, but such reports have been disputed for the lack of direct dating of the human remains and insufficient documentation of stratigraphy and taphonomy. By tracing possible burial process and conducting direct dating for an early Late Pleistocene paleontological site of Punung III, East Java, we here report a case that demonstrates how unexpected intrusion of recent human remains into older stratigraphic levels could occur in cave sediments. This further highlights the need of direct dating and taphonomic assessment before accepting either model. We also emphasize that the state of fossilization of bones and teeth is a useful guide for initial screening of recent intrusion and should be reported particularly when direct dating is unavailable. Additionally, we provide a revised stratigraphy and faunal list of Punung III, a key site that defines the tropical rainforest Punung Fauna during the early Late Pleistocene of the region.

Age control of the first appearance datum for Javanese Homo erectus in the Sangiran area.

The chronology of the World Heritage Site of Sangiran in Indonesia is crucial for the understanding of human dispersals and settlement in Asia in the Early Pleistocene (before 780,000 years ago). It has been controversial, however, especially regarding the timing of the earliest hominin migration into the Sangiran region. We use a method of combining fission-track and uranium-lead dating and present key ages to calibrate the lower (older) Sangiran hominin-bearing horizons. We conclude that the first appearance datum for the Sangiran hominins is most likely ~1.3 million years ago and less than 1.5 million years ago, which is markedly later than the dates that have been widely accepted for the past two decades.

Quaternary vertebrate faunas from Sumba, Indonesia: implications for Wallacean biogeography and evolution.

Historical patterns of diversity, biogeography and faunal turnover remain poorly understood for Wallacea, the biologically and geologically complex island region between the Asian and Australian continental shelves. A distinctive Quaternary vertebrate fauna containing the small-bodied hominin Homo floresiensis, pygmy Stegodon proboscideans, varanids and giant murids has been described from Flores, but Quaternary faunas are poorly known from most other Lesser Sunda Islands. We report the discovery of extensive new fossil vertebrate collections from Pleistocene and Holocene deposits on Sumba, a large Wallacean island situated less than 50 km south of Flores. A fossil assemblage recovered from a Pleistocene deposit at Lewapaku in the interior highlands of Sumba, which may be close to 1 million years old, contains a series of skeletal elements of a very small Stegodon referable to S. sumbaensis, a tooth attributable to Varanus komodoensis, and fragmentary remains of unidentified giant murids. Holocene cave deposits at Mahaniwa dated to approximately 2000-3500 BP yielded extensive material of two new genera of endemic large-bodied murids, as well as fossils of an extinct frugivorous varanid. This new baseline for reconstructing Wallacean faunal histories reveals that Sumba's Quaternary vertebrate fauna, although phylogenetically distinctive, was comparable in diversity and composition to the Quaternary fauna of Flores, suggesting that similar assemblages may have characterized Quaternary terrestrial ecosystems on many or all of the larger Lesser Sunda Islands.

Homo floresiensis-like fossils from the early Middle Pleistocene of Flores.

The evolutionary origin of Homo floresiensis, a diminutive hominin species previously known only by skeletal remains from Liang Bua in western Flores, Indonesia, has been intensively debated. It is a matter of controversy whether this primitive form, dated to the Late Pleistocene, evolved from early Asian Homo erectus and represents a unique and striking case of evolutionary reversal in hominin body and brain size within an insular environment. The alternative hypothesis is that H. floresiensis derived from an older, smaller-brained member of our genus, such as Homo habilis, or perhaps even late Australopithecus, signalling a hitherto undocumented dispersal of hominins from Africa into eastern Asia by two million years ago (2 Ma). Here we describe hominin fossils excavated in 2014 from an early Middle Pleistocene site (Mata Menge) in the So'a Basin of central Flores. These specimens comprise a mandible fragment and six isolated teeth belonging to at least three small-jawed and small-toothed individuals. Dating to ~0.7 Ma, these fossils now constitute the oldest hominin remains from Flores. The Mata Menge mandible and teeth are similar in dimensions and morphological characteristics to those of H. floresiensis from Liang Bua. The exception is the mandibular first molar, which retains a more primitive condition. Notably, the Mata Menge mandible and molar are even smaller in size than those of the two existing H. floresiensis individuals from Liang Bua. The Mata Menge fossils are derived compared with Australopithecus and H. habilis, and so tend to support the view that H. floresiensis is a dwarfed descendent of early Asian H. erectus. Our findings suggest that hominins on Flores had acquired extremely small body size and other morphological traits specific to H. floresiensis at an unexpectedly early time.

Age and context of the oldest known hominin fossils from Flores.

Recent excavations at the early Middle Pleistocene site of Mata Menge in the So'a Basin of central Flores, Indonesia, have yielded hominin fossils attributed to a population ancestral to Late Pleistocene Homo floresiensis. Here we describe the age and context of the Mata Menge hominin specimens and associated archaeological findings. The fluvial sandstone layer from which the in situ fossils were excavated in 2014 was deposited in a small valley stream around 700 thousand years ago, as indicated by (40)Ar/(39)Ar and fission track dates on stratigraphically bracketing volcanic ash and pyroclastic density current deposits, in combination with coupled uranium-series and electron spin resonance dating of fossil teeth. Palaeoenvironmental data indicate a relatively dry climate in the So'a Basin during the early Middle Pleistocene, while various lines of evidence suggest the hominins inhabited a savannah-like open grassland habitat with a wetland component. The hominin fossils occur alongside the remains of an insular fauna and a simple stone technology that is markedly similar to that associated with Late Pleistocene H. floresiensis.