DOI: 10.15468/qshj7d
title: First occurrence of Duboisia (Bovidae, Artiodactyla, Mammalia) from Thailand

description: This dataset contains the digitized treatments in Plazi based on the original journal article Nishioka, Yuichiro, Correspondence, Chavalit Vidthayanon (2018): First occurrence of Duboisia (Bovidae, Artiodactyla, Mammalia) from Thailand. Fossil Record 21 (2): 291-299, DOI: 10.5194/fr-21-291-2018, URL: http://dx.doi.org/10.5194/fr-21-291-2018Abstract. The first fossil record of Duboisia (Boselaphini, Bovidae) from Thailand confirms that this genus is no longer endemic to Java, Indonesia. The new fossil material is a calvarium with horn cores (older than the Middle Pleistocene) collected from a sandpit at Tha Chang, Nakhon Ratchasima Province, north-eastern Thailand. The present specimen is provisionally allocated to a species of Duboisia aff. D. santeng, which has weaker precornual ridges and anterior keels on the horn cores than D. santeng from Early and Middle Pleistocene deposits of Java, but these species share basic characteristics of horn cores as follows: the lower half inclined backwards; the upper half curved upwards; cross section rounded triangular, antero-posteriorly compressed, and with medial and lateral keels. Morphological similarities between D. aff. santeng and D. santeng support a strong faunal interchange between continental South East Asia and Java before the Middle Pleistocene, and suggest that the genus Duboisia diverged from the other genera of Boselaphini in the “Siva-Malayan” region.1 IntroductionSouth East Asia is geographically divided from the Indian subcontinent by the Himalayan–Tibetan Plateau, the Indo-Burma Range, and the Ganges and Brahmaputra rivers. These barriers form a zoogeographical boundary for terrestrial mammals between the Indo-Chinese and Indian subregions (Corbet and Hill, 1992). The Neogene fauna of continental South East Asia is similar to that of the Siwaliks, in the Indo-Pakistan area (e.g. Stamp, 1922; Colbert, 1938), but recent studies based on mammalian fossils from the Irrawaddy beds (Middle Miocene to Early Pleistocene) of Myanmar have demonstrated a faunal difference between the Siwaliks and Irrawaddy beds, which had increased since the Late Miocene or Early Pliocene due to forming zoogeographical barriers (Nishioka et al., 2015, 2018b; Takai et al., 2016).Mammalian endemism in South East Asia had increased during the Plio-Pleistocene (e.g. Van den Bergh et al., 2001; Van der Geer et al., 2010). The latest Pliocene and Early Pleistocene Satir fauna from Java, Indonesia, is impoverished and unbalanced and includes mammals of “Siva-Malayan” origin, such as Hexaprotodon sivajavanicus (Hippopotamidae, Artiodactyla) and Sinomastodon bumiajuensis (Proboscidea) (Sondaar, 1984). These mammals have been traditionally believed as endemic species to Java (Van der Maarel, 1932; Hooijer, 1950), but to what degree island species differ from the original continental species from the Siwaliks and the Irrawaddy beds is insufficiently studied (Van der Geer et al., 2010).The “ Stegodon – Homo erectus fauna” from the Early– Middle Pleistocene of Java (e.g. Trinil HK and Sangiran dome) is characterized by a relatively low degree of endemism and is composed of Siwalik species such as Pachycrocuta brevirostris (Carnivora) and Javanese species such as Stegodon trigonocephalus (Proboscidea) derived from mammals of the “Siva-Malayan” origin (Van der Geer et al., 2010). Duboisia santeng is an endemic species of Boselaphini (Bovidae, Artiodactyla) in the Early–Middle Pleistocene fauna of Java, which represents a somewhat isolated environment (Hooijer, 1958; Aimi and Aziz, 1985; Van den Bergh et al., 2001; Rozzi et al., 2013). D. santeng is phylogenetically related to living Indian boselaphins, Boselaphus tragocamelus and Tetracerus quadricornis (Stremme, 1911; Pilgrim, 1939; Hooijer, 1958). However, when a putative ancestor of D. santeng colonized Java is still debatable (Rozzi et al., 2013), owing to the absence of certain fossil evidence on continental South East Asia to show a relationship between Javanese D. santeng and Indian Boselaphini.Out of Java, Moigne et al. (2016) reported three isolated teeth belonging to the genus Duboisia from the Upper Pliocene Masol Formation of the Siwaliks, India, although they did not mention detail morphological comparisons on the basis of apomorphic characteristics of each taxon. The presence of Duboisia in continental South East Asia was mentioned by Hooijer (1962), based on some dental and postcranial remains from Quaternary cave deposits at Tambun, Peninsular Malaysia. However, we are not sure if this identification is valid because of the fragmentary nature of the remains. Furthermore, all specimens of D. santeng in the Hooijer collection are missing (Lim, 2013). A partial cranium of Duboisia was recently found from central Myanmar (but without geological context), which gives preliminarily evidence suggesting the existence of the genus on continental South East Asia (Nishioka et al., 2018b). In the present study, we describe the first specimen of Duboisia from Thailand. The specimen is a skull with complete horn cores that are useful for taxonomic comparisons of Duboisia remains between continental and island specimens from South East Asia.