Palaeogeography, Palaeoclimatology, Palaeoecology 243 (2007) 152–173 www.elsevier.com/locate/palaeo Characteristics of Pleistocene megafauna extinctions in Southeast Asia ⁎ Julien Louys a,b, , Darren Curnoe a, Haowen Tong c a Department of Anatomy, School of Medical Sciences, University of NSW, Sydney 2052, Australia b School of Biological, Earth and Environmental Sciences, University of NSW, Sydney 2052, Australia c Institute of Vertebrate Palaeontology and Palaeoanthropology, Chinese Academy of Sciences, 100044 Beijing, China Received 27 October 2005; received in revised form 13 July 2006; accepted 14 July 2006 Abstract The extinction of large-bodied taxa from the Pleistocene in Southeast Asia is examined. Although the chronological resolution of these extinctions is poor, and number of excavations in the region relatively few, broad characteristics of these extinctions can be described. Many taxa which became extinct appear to have been endemic to regions within Southeast Asia, while some taxa which experienced extinction or severe range reduction occurred in several regions. Members of the latter group include proboscideans (Stegodon and Palaeloxodon), the pygmy hippopotamus (Hexaprotodon), the orangutan (Pongo), hyenas (Crocuta and Hyaena), the giant panda (Ailuropoda), tapirs (Tapirus and Megatapirus), rhinoceroses (Rhinoceros), and the giant Asian ape Giganto- pithecus. The loss of these species cannot be assigned to a single cause. Rather their disappearance is likely tied to both climatic and human agents. Unlike other regions which experienced megafauna extinctions, eustatic changes in sea level in Southeast Asia seems to have been an important factor. © 2006 Elsevier B.V. All rights reserved. Keywords: Pleistocene; Extinction; Megafauna; Southeast Asia 1. Introduction mate) causative model (e.g. Barnosky et al., 2004; Wroe et al., 2004). Despite an ever growing body of The extinction of large-bodied species in the Late work concerned with megafaunal extinctions in many Pleistocene has been observed on every continent save parts of the world, the history of their disappearances Antarctica. The causes of extinctions have tradition- remain virtually unstudied in several geographic ally been divided into two camps—human agents or regions. In particular, the extinction of megafauna in climatic agents, although increasingly researchers are Southeast Asia and South America has received little opting for a multi-agent (including humans and cli- scrutiny. In the case of Southeast Asia, this has largely been the result of a poor chronology for these ex- tinctions (Martin, 1984). However, poor chronology does not prevent discussion of the extinction. While ⁎ Corresponding author. Present address: School of Biological, Earth and Environmental Sciences, University of NSW, Sydney, NSW, 2052, several studies have examined extinctions in South- Australia. Tel.: +612 93852125; fax: +612 93858016. east Asia (e.g. Medway, 1972, 1977; Sondaar, 1987; E-mail address: [email protected] (J. Louys). Tougard et al., 1996; Cranbrook, 2000, Cranbrook et 0031-0182/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.palaeo.2006.07.011 J. Louys et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 243 (2007) 152–173 153 al., 2000), these have been restricted to particular tax- mals within the same order often exhibit a similar range onomic or geographic groups. This region provides an of size variation (Smith et al., 2004), it can be safely interesting case study whereby several possible mech- assumed that those extinct species examined will not anisms of extinction can be examined. exhibit radically different body proportions to those of It has long been thought that extinctions in Africa were their most closely related living forms. The orders stud- less severe than in other regions of the world due to the ied are Primates, Carnivora, Proboscidea, Artiodactyla long term coevolution of humans and megafauna (Martin, and Perissodactyla. Only the latter three orders have a 1966; Barnosky et al., 2004). In Southeast Asia however, mean body mass greater than the average definition of this period of coevolution did not occur, although the megafauna (N44 kg as per Martin (1984); Table 1). region has experienced the greatest duration of hominin However, it was felt that an examination of Carnivora habitation outside of Africa. If anything, the extinction would be prudent for two reasons: firstly, any loss of record of Southeast Asia should parallel Europe, where it herbivores from the overall biomass would undoubtedly is commonly assumed that hunting for over 400,000 years affect carnivores, regardless of body mass. Secondly, it of megafauna was not detrimental to their survival, and is generally recognised that large body mass in mam- that it was only the emergence of behaviourally modern mals is a response to the need to digest low quality veg- humans which led to acceleration of extinctions (Bar- etation (Owen-Smith, 1992). It is axiomatic that these nosky et al., 2004). Unlike Europe, but like Africa, principles will not affect the Carnivora (with the notable Southeast Asia continues to host a number of extremely exception of the giant panda), and that (terrestrial) car- large-bodied species, including the Asian elephant and the nivores are unlikely to achieve the body masses of their rhinoceros. herbivorous prey. With respect to the primates, although Southeast Asia also holds special significance for the they generally have a smaller body mass, this is not true extinctions in Greater Australia (Sahul). The hypothesis of the apes: their mass falls within the common def- that extinctions occurred soon after the first arrival of inition of “megafauna”. humans in Sahul is commonly accepted (e.g. Miller et al., Extinction lists were compiled from published litera- 1999; Roberts et al., 2001; Miller et al., 2005), and is ture (Tables 2–11), by comparing Pleistocene faunal dependent on the assumption that the first Australians assemblages with extant taxa (compiled from Corbet and either hunted the megafauna or created significant habitat Hill, 1992; Nowak, 1999). Taxonomic nomenclature alteration resulting in their extinction. We argue that in follows Nowak (1999) for extant species, McKenna and order to understand the role of humans on the Australian Bell (1997) for extinct genera and Corbet and Hill (1992) ecosystem, it is necessary to also examine the effect and for extant genera but extinct species, except for ecology of their ancestors—in this case, Southeast Proboscidean taxonomy, which follows Shoshani and Asians. Tassy (2005). The subdivision of the Pleistocene into Early (2.5 Mya to 780 kya), Middle (780 kya to 128 kya) 2. Methodology and Late (128 kya to 11 kya) follows Jablonski and Whitford (1999). Extinction lists are sorted according to We decided to restrict this analysis to five orders of country, period and site (Tables 2–11). In the following (mostly) large bodied taxa (Table 1) owing to an often analysis, any species designated “c.f.” is treated as the arbitrary and subjective application of the term “mega- conferred species; a species designated “sp.” is ignored if fauna” (see Marshall, 1984; Wroe et al., 2004), com- another species of the same genus is present in the site, as bined with a scarcity of papers dealing with body mass these taxa may be conspecific. Our analysis is confined to estimates for extinct species in Southeast Asia. As mam- the species and genus levels, with subspecies ignored. Taxa unassigned above genus level have not been in- cluded. Thus, our analysis provides a minimum estimate Table 1 of extinction. Mean body mass of the five orders examined Southeast Asia as discussed in this paper is de- Order Mean body mass (grams) fined as the area of land south of the Yangtze river in China, and west of Huxley's line (which runs be- Artiodactyla 47,863 Carnivora 3548 tween Bali and Lombok in the south, between Borneo Primates 1778 and Sulawesi, and west of the Phillipines; Figs. 1– Perrisodactyla 398,107 3). Biogeographically, Southeast Asia can be split in- Proboscidea 5,128,614 to two distinct provinces—the Indochinese Province Adapted from Smith et al. (2004) and Smith et al. (2003). (consisting of southern China, Burma/Myanmar, Laos, 154 J. Louys et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 243 (2007) 152–173 Cambodia, Vietnam and northern Thailand) and the The Middle Pleistocene has far fewer generic Sundaic Province (consisting of southern Thailand, extinctions. This period saw the extinction of the last Malaysia, Sumatra, Java and Borneo) on the basis of members of Equus and Gigantopithecus in the region. climatic, botanical and zoological factors (Lekagul and Northern Chinese hominins specialised in predation on McNeely, 1988; Gray et al., 1994; Tougard, 2001). Equus until at least Middle Pleistocene times (Keates, Each province was separated into their individual 2003), and evidence suggests that early settlers roasted countries (Thailand was grouped within the Indochi- horse heads at Zhoukoudian (Binford and Stone, 1986). nese province as all sites examined from this country Equus is also one genus thought to have been hunted to are situated in northern Thailand) and taxa were exam- extinction by early Clovis hunters in North America ined independently for each. Countries share a num- (Martin, 1984), as it coincides with the colonisation of ber of extinctions or range reductions of the same the Americas by humans (Barnosky et al., 2004). The genera