The greater one-horned rhino, R. unicornis, is the least endangered of the Asian species nowadays, with ca. 2850 individuals scattered in several reserves from the Himalayan foothills, in northern India, southern Nepal, and Bhutan (Fig. 2). Its Holocene distribution was much wider and encompassed the entire Himalayan foothills, from Pakistan to easternmost India (Indian subregion). No Holocene occurrence is reported in Indochina, whereas R. unicornis is recorded in Pleistocene deposits throughout southern Asia, including the Indochinese Province and South China (Fig. 3). The greater one-horned rhino occurred in the Early Pleistocene of Java (Joordens et al., 2009), South China, and Indo-Pakistan, in the Middle Pleistocene of Java and the Indochinese subregion (Thailand, Laos, Vietnam, and South China), and in the Late Pleistocene of Vietnam, South China (Fig. 3), South India, and Sri Lanka (Chauhan, 2008 and Nanda, 2002).

Its sister taxon, the Javan rhino Rhinoceros sondaicus–or “lesser one-horned rhino”–, is critically endangered today (van Strien et al., 2008a). No more than 50 individuals survive, with a main population located in Java, Indonesia (Ujung Kulon Reserve; Fig. 2) and perhaps a small group of three or four individuals in southern Vietnam (Cat Loc, Cat Tien National Park; Fig. 2). By contrast, during the Holocene, the Javan rhino was common from east to west and from north to south of the Indochinese Peninsula (e.g., Long Spean locality, southern Cambodia; Guérin and Mourer, 1969), as well as in eastern China (Fig. 2; Rookmaaker, 2006, Tong, 2000 and Tong, 2001) and in the Sundaic subregion (Fig. 2; peninsular Malaysia, Sumatra, Borneo, and Java; Cranbrook and Piper, 2007). R. sondaicus is well represented in the Early Pleistocene of Java (Djetis, Sangiran, and Trinil localities; Joordens et al., 2009 and van den Bergh et al., 2001), in the Middle Pleistocene of Indochina (Cambodia, Thailand, and Laos) and Peninsular Malaysia (Tambun; Fig. 3), and in the Late Pleistocene of the Sundaic subregion (Sumatra, Java, and Malaysia) and northern Vietnam (Ma U’Oi, Duoi U’Oi, and Lang Trang; Fig. 3; Bacon et al., 2004 and Bacon et al., 2008a). Two fossil subspecies were named for late Middle Pleistocene remains from Phnom Loang, Cambodia (R. s. guthi; Beden et al., 1972) and Kedung Brubus, Java (R. s. sivasondaicus; Guérin and Faure, 2002).

The Sumatran rhino, Dicerorhinus sumatrensis, is two-horned and smaller than the representatives of Rhinoceros (i.e., body mass is less than 1000 kg; Groves and Kurt, 1972 and Guérin, 1980). Its phylogenetic affinities are controversial on both morphological and molecular grounds (Antoine, 2002, Antoine, 2005, Cerdeño, 1995, Orlando et al., 2003 and Tougard, 2001). Its population, estimated at ca. 200 individuals, is highly fragmented in several small groups from Sumatra and Malaysia (Fig. 2). It is therefore considered as critically endangered, due to the drastic demographic decline suffered in the last decades (van Strien et al., 2008b). D. sumatrensis had a much wider Holocene range than now, covering most of the Indo-Malayan region (Fig. 2; eastern India [Indian subregion]; northern Laos [Holocene alluvium at Tam Hang]; Arambourg and Fromaget, 1938), Myanmar, Thailand, and eastern China (Indochinese subregion and Palearctic region; Fig. 2); Malaysia, Sumatra, and Borneo (Sundaic subregion). Until Recent times, the “hairy rhino” was co-occurring with R. sondaicus in most of its geographical range (Fig. 2). The Sumatran rhino has a scarce Pleistocene record, with a single attested occurrence for the Early Pleistocene (Liucheng or “Gigantopithecus cave”, South China; Fig. 3; Tong and Guérin, 2009) and the late Middle Pleistocene (Ban Fa Suai, Thailand; Fig. 3; pers. obs.), but a wider Late Pleistocene range (Laos, northern Vietnam, and Sumatra; Fig. 3).

More than a dozen fossil species of Rhinoceros were named in southern Asia, the validity of which is more or less questionable (e.g., Bacon et al., 2008b, Laurie et al., 1983 and Tong, 2001) (Fig. 3).

In our opinion, R. unicornis encompasses all large Rhinoceros remains from South Asia that were formerly included within the wastebasket species R. sinensis (and its junior synonyms R. oweni, R. plicidens, R. simplicidens, or R. chiai; Tong, 2001), the Javan R. kendengindicus (Bacon et al., 2008b and Hooijer, 1949), as well as the Indo-Pakistani R. sivalensis, R. palaeindicus, R. deccanensis, R. sinhaleyus, or R. kagavena (Tong, 2001). Rhinoceros sinensis was primarily described in Yengshingkuo, China and recognized in most Middle Pleistocene localities of South China (Colbert, 1938 and Tong, 2001) and northern Vietnam (Fig. 3; Patte, 1928 and Tougard, 2001); only a thorough revision of the hypodigm of R. sinensis would allow assessing the eventual availability of this species and its affinities within Rhinoceros and with other rhinocerotines (Tong and Wu, 2010).

The endemic ? Pleistocene species Rhinoceros philippinensis is based on a jaw extracted from a fossil bed of unknown location and age in Luzon, Philippines (Fig. 1; Reis and Garong, 2001, Tougard, 2001 and von Koenigswald, 1956). Reis and Garong (2001: 411) consider that the “occurrence of this species may not be natural”. Its specific status is therefore highly dubious.

Dicerorhinus gwebinensis is a small two-horned rhino from the Upper Irrawaddy deposits of western Myanmar (Gwebin locality, Fig. 3; Zin-Maung-Maung-Thein et al., 2008) the hypodigm of which is restricted to a skull and the associated mandible, much similar to D. sumatrensis, but with shorter and thicker nasals. The Upper Irrawaddy beds yielding D. gwebinensis are most probably of Early Pleistocene age (Louys et al., 2007).

The gigantic two-horned Stephanorhinus kirchbergensis is also known as the “forest rhino”, with junior synonyms as widely used as Dicerorhinus mercki (Middle Pleistocene of the Palearctic region; van der Made, 2010), or more local names such as D. choukoutienensis, D. lantianensis, and D. yunchuchenensis (Early to Late Pleistocene of eastern central China; Tong, 2000 and Tong, 2001). As far as South Asia is concerned, S. kirchbergensis occurred throughout the Pleistocene epoch in eastern central China, but only within the Beijing-Xian-Shanghai triangle, i.e. between 30° and 40°N (Tong, 2000). It is quite rare in South Chinese faunal assemblages (Tong and Wu, 2010). The presence of “R. mercki” (= S. kirchbergensis) in “Préah Vihear”, Cambodia (= Phnom Loang; Fig. 3), as mentioned by Carbonnel and Guth (1968) and Louys et al. (2007), is highly dubious: other revisions of the rhinocerotine material from the same locality do not mention this taxon (e.g., Beden et al., 1972).

The fossil genus Coelodonta encompasses large two-horned rhinos with an ossified nasal septum. The earliest representatives of Coelodonta are known in the Early Pleistocene of northeastern China (Nihowan area) and referred to as C. nihowanensis (Tong, 2001). Later representatives document the much more widespread C. antiquitatis, also known as “woolly rhino” (Middle and Late Pleistocene of the Palearctic region; Guérin, 1980, Tong, 2001 and Tong, 2004). No representative of Coelodonta is recorded in southern Asia (Tong, 2000).

Punjabitherium platyrhinus is another large two-horned rhino, ranging from the latest Pliocene to the early Middle Pleistocene in North India and Pakistan (Upper Siwaliks; Colbert, 1935, Khan, 1971, Matthew, 1929 and Nanda, 2002). P. platyrhinus is endemic to the Indian subregion; there is no record of it in other Indo-Malayan subregions or in the Palearctic region.

The Early Pleistocene period in the Indochinese subregion is poorly documented (Fig. 3); the only recognized rhinocerotids are Dicerorhinus gwebinensis and Rhinoceros sp. from Gwebin, Myanmar (Upper Irrawaddy beds; Zin-Maung-Maung-Thein et al., 2008), D. sumatrensis from the Liucheng Gigantopithecus Cave in South China (Tong and Guérin, 2009), and the bispecific assemblage [Rhinoceros unicornis (“R. sinensis”) + R. sp.] from Yuanmou, South China (Tong, 2000). The assemblages [Punjabitherium platyrhinus + R. unicornis] and [R. unicornis + R. sondaicus] characterize the Indian subregion (Himalayan foothills; Nanda, 2002) and the Sundaic subregion (Djetis, Java; van den Bergh et al., 2001), respectively. R. sondaicus occurs also in Sangiran and Trinil, Java (Fig. 3; van den Bergh et al., 2001).

Central and northern China (Palearctic region) show a distinct rhinocerotine fauna, with R. unicornis (“R. sinensis”;  < 30°N), Stephanorhinus kirchbergensis (between 30° and 40°N), and Coelodonta nihewanensis (> 30°N; Tong, 2000, Tong, 2001 and Tong and Moigne, 2000). The assemblage [C. nihewanensis + D. kirchbergensis] is restricted to the Early Pleistocene of central eastern China (Tong, 2000).

Compared to the Early Pleistocene, the middle Pleistocene period – especially the late middle Pleistocene – provides a much better fossil rhinocerotid record in Indochina (Fig. 3). All three recent rhino species occur in the Indochinese Peninsula, with R. unicornis (Yenangyaung, Myanmar; Hang Hum, Tham Om, Keo Leng, Tham Khuyen, and Tham Hai, Vietnam), R. sondaicus (Thum Phra Khai Phet, Thailand; Phnom Loang, Cambodia), both of them (Thum Wiman Nakin, Thailand; Tam Hang, Laos), or the assemblage [R. unicornis + D. sumatrensis] as in Ban Fa Suai, Thailand (Bacon et al., 2004, Bacon et al., 2006, Bacon et al., 2008a, Bacon et al., 2008b, Tougard, 2001 and Zeitoun et al., 2005). R. sp. is mentioned in Mogok Cave, Myanmar (Fig. 3).

In adjacent areas, R. unicornis occurs in South China (Hsingan) and central eastern China (Yanhuidong, Koloshan, Yengshingkuo), while S. kirchbergensis is restricted to central eastern China (e.g., Chiaoxian and Hexian; Fig. 3), and C. antiquitatis to northeastern China (Bacon et al., 2008b and Tong, 2000). Accordingly, the only Middle Pleistocene bispecific rhinocerotid assemblage in China consists of [S. kirchbergensis + C. antiquitatis], between 30°N and 40°N (Tong, 2000; Table 1, Fig. 1). The early Middle Pleistocene period coincides with the last occurrence of P. platyrhinus in the Indian subregion while R. unicornis is common throughout the Middle Pleistocene in the same area (Nanda, 2002). The Middle Pleistocene of the Sundaic subregion only yields R. sondaicus (Tambun, Peninsular Malaysia; Fig. 3) and the assemblage [R. unicornis + R. sondaicus] in Kedung Brubus, Java (Fig. 3; Bacon et al., 2008b, Hooijer, 1946 and Hooijer, 1949).

Only three Vietnamese localities with rhinocerotids document the Late Pleistocene interval (Fig. 3). All of them yield distinct rhinocerotid assemblages involving recent species: [R. sondaicus + D. sumatrensis] in Lang Trang, [R. unicornis + R. sondaicus] in Ma U’Oi, and [R. unicornis + R. sondaicus + D. sumatrensis] in Duoi U’Oi (Bacon et al., 2006 and Bacon et al., 2008b). Aside from the Indochinese Peninsula, R. unicornis occurs in South China (Fig. 3), as well as in the Indian subregion (India, Sri Lanka, and Pakistan; Chauhan, 2008 and Nanda, 2002). The assemblage [S. kirchbergensis + C. antiquitatis], first appearing in the early Middle Pleistocene of central eastern China, persists during the Early and Middle-Late Pleistocene in the same area (Tong, 2000). C. antiquitatis gets more and more documented in the Latest Pleistocene of northeastern China (Tong, 2000, Tong, 2004 and Tong and Moigne, 2000). R. sondaicus is the only rhinocerotid species reported in the Late Pleistocene of Java (Punung and Gunung Dawung; Fig. 3) and Malaysian Borneo (Niah cave; Bacon et al., 2008b). D. sumatrensis occurs in Sumatra at Lida Ajer and Sibrambang (Fig. 3); it co-occurs with R. sondaicus in Sibrambang (Bacon et al., 2008b).

The Holocene rhinocerotid record consists only of recent species in the Indo-Malayan region (Corbet and Hill, 1992 and Nowak, 1999) and eastern China (e.g., Dongshan and Xiawanggang localities; Fig. 2; Rookmaaker, 2006, Tong, 2000 and Wang et al., 1993). R. unicornis is the northernmost and westernmost species, with a range encompassing the Himalayan Foothills (Indian subregion) but excluding the Indochinese subregion (Fig. 2). R. sondaicus occurs throughout the Indochinese Peninsula and the Sundaic subregion, including the Loang Spean Neolithic site, in western Cambodia (Guérin and Mourer, 1969); the Javan rhino (R. sondaicus) is the only Holocene rhinocerotid species recorded in Java (Fig. 2). D. sumatrensis co-occurs with R. sondaicus in the Indian subregion (eastern India), in the western and northern parts of the Indochinese Peninsula (Myanmar, Thailand, and Laos; South China), and in the Sundaic subregion (Peninsular Malaysia and Sumatra; Fig. 2). The Holocene of Borneo yields mostly remains of D. sumatrensis (Fig. 2). D. sumatrensis is mentioned in the superficial alluvium of Tam Hang, northern Laos (Holocene; Arambourg and Fromaget, 1938).

Assam and Nagaland, in northeastern India, are the only regions which hosted the plurispecific assemblage [R. unicornis + R. sondaicus + D. sumatrensis] during the Holocene period (Fig. 2). The same rhinocerotid assemblage is recorded in Duoi U’Oi (Late Pleistocene, Vietnam; Bacon et al., 2008b), which would point to similar environmental conditions for both areas (subtropical moist forest under a monsoonal climate).

South China (Indochinese subregion) – South China's Pleistocene rhinocerotid record is highly similar to the Indochinese record, at least at genus level, with the co-occurrence of the assemblage [small-sized Dicerorhinus + Rhinoceros unicornis] in the Early Pleistocene, the prominence of Rhinoceros in the Middle Pleistocene of both areas, and the absence of large two-horned rhinos such as Stephanorhinus and Coelodonta, which occurred in central and northern China (Fig. 3; Tong, 2000, Tong, 2004 and Tong and Moigne, 2000). On the other hand, R. sondaicus is common in Middle and Late Pleistocene Indochinese localities whereas it is not attested in South China before the Holocene (Fig. 2 and Fig. 3): following Wang et al. (1993) and Rookmaaker (2006), it was widespread and sometimes associated with D. sumatrensis south of the Yellow River from Shang up to Qing dynasties (2000 BC–200 AC). The southward retreat and final extinction of R. sondaicus and D. sumatrensis in China ca. 200 years ago was due to hunting and “the human destruction of their environment” (Rookmaaker, 2006: 104). Only a thorough revision of the wastebasket taxon “Rhinoceros sinensis” would allow to state about eventual Pleistocene occurrences of the Javan rhino in South China.

Sundaic subregion–The only rhinocerotid recorded in Peninsular Malaysia is R. sondaicus, from the late Middle Pleistocene of Tambun (Fig. 3; Tougard, 2001). R. sondaicus and D. sumatrensis co-occurred in the Late Pleistocene of Sumatra, at Sibrambang (ca. 80–60 ka; Bacon et al., 2008b, Hooijer, 1946 and Tougard, 2001). Java yields a much more documented rhinocerotid fossil record, with Rhinoceros kendengindicus and R. sivasondaicus, from the Pleistocene of Java, being considered junior synonyms of R. unicornis and R. sondaicus, respectively (Hooijer, 1949 and Laurie et al., 1983). In Java, R. sondaicus has a continuous range from the Early Pleistocene (Fig. 3; Sangiran, Djetis, and Trinil localities) up to Recent times, whereas R. unicornis is restricted to Early and Middle Pleistocene deposits (Fig. 3; Djetis, Kedung Brubus; Hooijer, 1946, Hooijer, 1949 and van den Bergh et al., 2001). There is no attested occurrence of D. sumatrensis or any other rhinocerotid species but R. sondaicus in the Late Pleistocene and the Holocene of Java (Bouteaux et al., 2007 and van den Bergh et al., 2001). After Cranbrook and Piper (2007), two postcranial bones found in cave deposits attest to the presence of R. sondaicus in the Latest Pleistocene (Niah, ca. 14 ka; Fig. 3) and the Holocene (Madai, ca. 4 ka; Fig. 2) of Borneo. Reis and Garong (2001) do not mention any rhinocerotid in the Late Pleistocene-Early Holocene of the Palawan Island (Philippines, Sundaic subregion; Fig. 1).

Philippine subregion – Aside from the jaw of Rhinoceros philippinensis (unknown age, Luzon; Reis and Garong, 2001, Tougard, 2001 and von Koenigswald, 1956), other unidentified rhino specimens from the Philippines Archipelago were found in Mindanao (Fig. 1); all of them are human-related or they were found without any stratigraphical control (Bautista, 1995 and Reis and Garong, 2001).

Wallacean subregion – To our knowledge, there is no rhinocerotid record (fossil/recent) in the Wallacean subregion.

Indian subregion–By contrast, the Pleistocene and Holocene deposits of the Indian subregion yield many rhinocerotine rhinocerotid remains, sometimes through bispecific assemblages. The upper Siwaliks of India and Pakistan mostly yield R. unicornis, under the names Rhinoceros sivalensis and R. palaeindicus, with a virtually continuous fossil record from the Late Pliocene (ca. 3.3 Ma) up to recent times in northern Pakistan and northern India (Dennell et al., 2006 and Nanda, 2002). In the Latest Pliocene-early Middle Pleistocene interval (2.6-0.6 Ma) of the same area, R. unicornis co-occurs with Punjabitherium platyrhinus (Colbert, 1935, Khan, 1971, Matthew, 1929 and Nanda, 2002). Rhinoceros was also common throughout the Pleistocene of peninsular India and in the Late Pleistocene of Sri Lanka, under diverse specific names (Chauhan, 2008, Deraniyagala, 1992 and Hooijer, 1946).

Oceanic region – Neither fossil nor recent rhinocerotid is recorded in the Oceanian region, with the notable exception of a P1 unambiguously referable to the western Eurasian Miocene hornless teleoceratine Brachypotherium brachypus, found by gold diggers in New Caledonia in the 19th century. This tooth, probably used as a jewel by a French deported convict and subsequently lost by the Diahot River, was (mis)identified as documenting an in situ diprodontid marsupial of Australian affinities (Zygomaturus diahotensis; Guérin et al., 1981).

Palearctic region (northern China-Mongolia) – Rhinoceros sinensis (= R. unicornis) was recognized in dozens of southern Chinese localities, as well as in the late Early to early Middle Pleistocene faunas of Taiwan (Otsuka, 1984) and Japan (Kamei, 1981 and van den Bergh et al., 2001). Coelodonta was abundant throughout the Pleistocene epoch in most areas of the Palearctic region, including North and central China (north of 30°N; Tong, 2000 and Tong, 2001). The Middle Pleistocene of the Palearctic region also hosted the gigantic two-horned Stephanorhinus kirchbergensis (van der Made, 2010). The forest rhino (S. kirchbergensis) and the woolly rhino (C. antiquitatis) co-occurred in mid-latitudes of eastern China (between 30° and 40°N; Tong, 2000) but they are not recorded south of 30°N, most probably for climatic and environmental reasons (Tong, 2004).