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Elephas maximus and Stegodon orientalis were two keystone proboscideans in southern Asia that coexisted mainly after the Middle Pleistocene in many regions. The long-term paleoecology and possible foraging competition of these two species have not been intensively investigated yet. Here, we applied stable isotope (C, O) analysis to the tooth enamel of coexisting Elephas maximus, Stegodon orientalis, and other associated mammalian species in Quzai Cave, southern China, dated to the early Late Pleistocene, to explore their paleoenvironmental context and foraging ecology. The δ13C values of Elephas maximus were widely distributed between −17.9‰ and −11.9‰ (n = 10), while Stegodon orientalis δ13C values ranged from −16.7‰ to −14.7‰ (n = 7). These results suggest that Elephas maximus was possibly a mixed feeder with a broader range of dietary resources than Stegodon orientalis, which probably browsed on a narrower range of plant resources in more densely forested landscape. A chronological comparison (from 8 Ma to recent) of published δ13C data for these two species from Asia showed that none of them were dietary specialists. However, Elephas had a more flexible foraging ecology and a stronger ability to exploit abrasive grasses than Stegodon. The niche partitioning and perceived different foraging behaviors of Stegodon and Elephas might have reduced the level of interspecific competition and allowed them to coexist during the Pleistocene. Moreover, the high-level of ecological flexibility of Elephas might have helped them to survive until the present day, while Stegodon eventually went extinct by the terminal Pleistocene ∼12 ka. An extensive comparison and evaluation of the δ13C data from fossil mammals in mainland southeast Asia during the Early to Late Pleistocene suggests that southern China was dominated by C3 vegetation throughout the Pleistocene, in contrast with the evidence of C4 biomes in neighboring Laos, Cambodia, and Thailand. Southern China experienced relatively stable environments during the Pleistocene, which can be attributed to the wide range of mountainous regions that acted as ecological refugia from human interference and climatic fluctuations, and allowed the preservation of high biodiversity. The isotopic data we present here provides new evidence about the ecological complexity of mainland southeast Asia and elucidates the need for more systematic research to investigate extinction models and ecological conservation in this region.

Flores represents a unique insular environment with an extensive record of Pleistocene fossil remains and stone artefacts. In the So'a Basin of central Flores these include endemic Stegodon, Komodo dragons, giant tortoises, rats, birds and hominins, and lithic artefacts that can be traced back to at least one million years ago (1 Ma). This comprehensive review presents important new data regarding the dating and faunal sequence of the So'a Basin, including the site of Mata Menge where Homo floresiensis-like fossils dating to approximately 0.7 Ma were discovered in 2014. By chemical fingerprinting key silicic tephra originating from local and distal eruptive sources we have now established basin-wide tephrostratigraphic correlations, and, together with new numerical ages, present an update of the chronostratigraphy of the So'a Basin, with major implications for the faunal sequence. These results show that a giant tortoise and the diminutive proboscidean Stegodon sondaari last occurred at the site of Tangi Talo ∼1.3 Ma, and not 0.9 Ma as previously thought. We also present new data suggesting that the disappearance of giant tortoise and S. sondaari from the sedimentary record occurred before, and/or was coincident with, the earliest hominin arrival, as evidenced by the first records of lithic artefacts occurring directly below the 1 Ma Wolo Sege Tephra. Artefacts become common in the younger layers, associated with a distinct fauna characterized by the medium-sized Stegodon florensis and giant rat Hooijeromys nusatenggara. Furthermore, we describe a newly discovered terrace fill, which extends the faunal record of Stegodon in the So'a Basin to the Late Pleistocene. Our evidence also suggests that the paleoenvironment of the So'a Basin became drier around the time of the observed faunal transition and arrival of hominins on the island, which could be related to an astronomically-forced climate response at the onset of the Mid-Pleistocene Transition (MPT; ∼1.25 Ma) leading to increased aridity and monsoonal intensity. publishedVersion

Understanding global patterns of late Quaternary megafaunal extinction is impeded by geographic variation in data quality and quantity. The magnitude, timing and drivers of megafaunal extinctions remain poorly understood for India, a region with a strong history of palaeontological research. We review available data for all putative extinct Indian megafaunal taxa with direct or indirect reported evidence of potential survival into the global “megafaunal extinction window” (from ∼50,000 years onwards). Assessment of late Quaternary megafaunal species richness is confused by multiple levels of taxonomic uncertainty, including the relationship of named Late Pleistocene taxa to extant taxa, and nomenclatural confusion over correct species names. There is sufficient evidence to recognise up to four genuine global megafaunal species-level extinctions in India during the Late Pleistocene: two proboscideans (Palaeoloxodon namadicus, Stegodon sp.), a hippopotamus (Hexaprotodon sp.), and possibly a horse (Equus namadicus). A fifth extinct megafaunal species, the Indian aurochs Bos [primigenius] namadicus, definitely persisted into the Holocene. Other Indian late Quaternary megafaunal species (Rhinoceros spp., Bubalus palaeindicus, Sus “palaeindicus”, Crocodylus palaeindicus) are likely to be synonyms of extant species. Reconstructing regional extinction dynamics is further impeded by chronological uncertainty; however, attempts to obtain new dates for vertebrate samples from six late Quaternary sites in five regions were unsuccessful. Accurate understanding of the dynamics of megafaunal extinctions in India will require robust taxonomic, chronological and palaeoecological data, and we encourage further investigation of the region’s rich late Quaternary record.

The dental evolution of Mammuthus during the Quaternary represents the ultimate level of adaptation to open habitats among all proboscideans. This is the end result of the increased trend in grazing ability in Elephantidae. The combination of mesiodistally flat molar plates and proal (from back to front) jaw movement allowed elephants to increase their grazing effectiveness to an extent that gomphotheres failed to achieve. This does not necessarily mean that this feature evolved as an adaptation to grazing. The acquisition of proal jaw movement in Elephantidae is not well delineated because of the poor fossil record of the earliest elephants. However, it seems that proal jaw movement can be developed independent of the adaptation to grazing. Stegolophodon from the Early Miocene of Japan (ca. 17.3 Ma) suggest that proal jaw movement was fully developed in stegolophodonts by 17.3 Ma. This date roughly coincides with the onset of the Miocene climatic optimum, but forested habitats remained in Southeast Asia and Japan. Thus, at that time, there was no climatic change that selected stegolophodonts to adapt to grazing. Stegodonts remained brachydont throughout their history. Stable carbon isotope data suggest that stegodonts had not become grazers before the latest Pliocene, and this may explain the differences between Elephantidae and Stegodontidae in molar height increase. On the other hand, the browsing habitat of most stegodonts fails to explain the increased number of loph(id)s in stegodonts subsequent to the latest Miocene.

Since its sub-aerial emergence, Java has experienced multiple tectonic, geographic and climatic changes, which affected the megafaunal occupation, adaptation and succession. Six Proboscidean taxa have been found from various localities throughout Java extending back to the Early to Late Pleistocene. The six taxa are: Stegoloxodon indonesicus, Sinomastodon bumiajuensis, pygmy Stegodon sp., Stegodon trigonocephalus, Elephas hysudrindicus and Elephas maximus, in which respective taxa are included in successive faunal stages. The aim of this research was to reconstruct the succession of Proboscidea in Java and the adaptation of each taxon to environmental changes by incorporating stable isotope analysis with the fossil faunal record, geology and stratigraphy. We conducted stable carbon (δ13C) and oxygen (δ18O) isotope analysis of the carbonate phase in the tooth enamel of six proboscidean taxa from numerous localities and ages. Our results suggest that for the earliest terrestrial fauna from Java, represented by Stegoloxodon indonesicus, the feeding ecology was restricted to a closed canopy rainforest during the earliest Pleistocene, while towards the late Early Pleistocene, the successive taxon, Sinomastodon bumiajuensis, was adapted to different or increasingly drier grassy habitats. C4 expansion on the island took place since the later part of the Early Pleistocene (before 1.5 Ma) and continued until the Middle Pleistocene, as suggested by the carbon and oxygen isotope composition of assemblages of proboscidean taxa from Sangiran, Kedung Brubus, Trinil, and western Java, which also predominantly display the expected range of C4-dominant feeders. However, the occurrence of mixed C3/C4 feeder Proboscidea in the Ngandong Fauna suggests that fragmented dense evergreen forests, shrubby or woodland vegetation reappeared towards the end of the Middle Pleistocene. This environmental shift is detected in the later stage of the Middle Pleistocene, as the dietary preference of all analysed samples from individuals from this age shifted back from a C4-dominated into a C3-dominated diet, which suggests a change from a dry to more humid climate conditions.

The finding of archaeological evidence predating 1 Ma and a small hominin species (Homo floresiensis) on Flores, Indonesia, has stimulated much research on its origins and ancestry. Here we take a different approach and examine two key questions – 1) how did the ancestors of H. floresiensis reach Flores and 2) what are the prospects and difficulties of estimating the likelihood of hominin persistence for over 1 million years on a small island? With regard to the first question, on the basis of the biogeography we conclude that the mammalian, avian, and reptilian fauna on Flores arrived from a number of sources including Java, Sulawesi and Sahul. Many of the terrestrial taxa were able to float or swim (e.g. stegodons, giant tortoises and the Komodo dragon), while the rodents and hominins probably accidentally rafted from Sulawesi, following the prevailing currents. The precise route by which hominins arrived on Flores cannot at present be determined, although a route from South Asia through Indochina, Sulawesi and hence Flores is tentatively supported on the basis of zoogeography. With regards to the second question, we find the archaeological record equivocal. A basic energetics model shows that a greater number of small-bodied hominins could persist on Flores than larger-bodied hominins (whether H. floresiensis is a dwarfed species or a descendent of an early small-bodied ancestor is immaterial here), which may in part explain their apparent long-term success. Yet the frequent tsunamis and volcanic eruptions in the region would certainly have affected all the taxa on the island, and at least one turnover event is recorded, when Stegodon sondaari became extinct. The question of the likelihood of persistence may be unanswerable until we know much more about the biology of H. floresiensis.

The Siwalik sequence saw the appearance and spread of the family Elephantidae in the Indian subcontinent during the Plio-Pleistocene epochs. Elephas flourished and underwent species turnover during the Plio-Pleistocene of the Siwalik Group. The newly discovered specimens include serially arranged M2-3 and partial maxillary fragment with M2 of Elephas planifrons, and M3 and partial dp4 of Elephas hysudricus from the Pinjor Formation (Pleistocene) of the Siwaliks. A tusk from the Tatrot Formation (Pliocene) of the Siwaliks, has been assigned to Elephantoidea indet. Based on the comparison with the stratigraphically well-dated mammalian fauna from the various Siwalik localities of the Indian subcontinent, the age of Sardhok, Panjan Sher Shahana and Kurla Sharif range is suggested to be from the Late Pliocene (Piacenzian) to Late Early Pleistocene (Calabrian), and a savannah like environment is suggested for these localities.

Late Quaternary megafaunal extinction chronologies are poorly understood across eastern and southeast Asia. Previous radiometric studies suggested that surprisingly many extinct late Pleistocene large mammal species survived into the Holocene in northern China (Bos primigenius, Coelodonta antiquitatis, Mammuthus primigenius) and southern China (Ailuropoda baconi, Crocuta [crocuta] ultima, Megatapirus augustus, Stegodon orientalis, Sus cf. xiaozhu), indicating that Chinese megafaunal extinctions may have been "staggered" across the Late Quaternary. We critically re-examined all radiometric evidence suggesting Holocene survival of Chinese Late Quaternary megafauna, and conducted new dating of mammal material from reportedly Holocene sites containing characteristically Late Pleistocene faunas. Evidence for Holocene survival of any Chinese Late Pleistocene megafaunal species is weak or untenable. No previous radiometric dates used to support Holocene megafaunal survival represent direct bone dates for species of interest, and stratigraphic association between material yielding Holocene dates and megafaunal remains is dubious at most sites. Concerns over accurate identification of faunal material further confuse claims for Holocene survival of many species. Robust radiometric last-occurrence dates for extinct Chinese megafauna are all restricted to the Late Pleistocene, similar to the timing of many other Late Quaternary megafaunal species extinctions elsewhere in Eurasia and the Americas. (c) 2013 Elsevier Ltd. All rights reserved.