J. Zool., Lond. (2005) 266, 25–35 C  2005 The Zoological Society of London Printed in the United Kingdom doi:10.1017/S0952836905006588 New phylogenetic perspectives among species of South-east Asian wild pig (Sus sp.) based on mtDNA sequences and morphometric data Vittorio Lucchini 1 , Erik Meijaard 2 , Cheong H. Diong 3 , Colin P. Groves 4 and Ettore Randi 1 * 1 Istituto Nazionale per la Fauna Selvatica (INFS), 40064 Ozzano Emilia (BO), Italy 2 School of Tropical Biology, James Cook University, P.O. Box 6811, QLD 4870, Australia 3 Natural Sciences, NIE, Nanyang Technological University, 637616 Singapore 4 School of Archaeology and Anthropology, Australian National University, Canberra, ACT 0200, Australia (Accepted 14 September 2004) Abstract There are more taxa of wild pig in South-east Asia (SEA) than in any other comparable area in the world, but the number of species and subspecies is still uncertain. The taxonomy of some wild pig populations distributed in Malaysia, Indonesia and the Philippines, was investigated using molecular and morphometric techniques. Our results suggest the existence of two main evolutionary clades that are likely to have diverged during the Pliocene in SEA: one including wild pig populations distributed in the Philippines (Sus cebifrons) and Sulawesi (S. celebensis); the other including the Indonesian and Malaysian bearded pigs (S. barbatus), and the widespread Eurasian wild boar (S. scrofa). A possible scenario for pig speciation in SEA is developed, and the need for a taxonomic revision of bearded pigs suggested, particularly concerning the taxonomic status of S. b. ahoenobarbus from Palawan Island, and the existence a new species distributed in the Tawi Tawi Islands (Philippines). Unexpectedly, bearded pigs in the Malay Peninsula are closely related to the Bornean population, but distinct from Sumatran S. barbatus, and they should be considered as belonging to a different subspecies. Key words: phylogeny, mtDNA, wild pig, Suidae, Sus, South-east Asia, Sundaland INTRODUCTION South-east Asia (SEA) has the highest wild pig diversity in the world. This was probably promoted by vicariance in archipelagos, where islands were repeatedly connected or isolated during the sea level fluctuations that have occurred since the Early Pliocene (c. 5.2 million years ago, Mya). Several studies have attempted to clarify the systematics of SEA wild pigs (Groves & Grubb, 1993; Grubb, 1993; Ranes, 1995; Groves, 1997; Oliver, 2001) but the number of species is still uncertain. Groves (1997) suggested that the genus Sus can be differentiated into three informal groups, named the S. verrucosus, S. philippensis and S. scrofa groups. The S. verrucosus group includes the Javan warty pig S. verrucosus, the bearded pig S. barbatus (from Borneo, Sumatra, Bangka, the Riau Archipelago, Palawan and the Malay Peninsula), the Sulawesi pig Sus celebensis, and the Visayan pig S. cebifrons. Males in this group have straight lower canines, in which the inferior surface is usually 120–150% of the posterior, and have warts when adult. Pigs in the *All correspondence to: E. Randi, Istituto Nazionale per la Fauna Selvatica (INFS), 40064 Ozzano Emilia (BO), Italy. E-mail: met0217@iperbole.bo.it S. philippensis group, in which the canine ratio is c. 140– 180%, have two pairs of warts, with a long thin tuft emerging from the one on the angle of the jaw. The S. scrofa group includes this species and the pygmy hog S. salvanius (endemic to India); the canine ratio is gener- ally < 100, and there are no warts. Phylogenetic relation- ships among these groups are unclear (Groves, 2001). Taxonomic uncertainty exists also at the subspecies level. Groves (1981) and Groves & Grubb (1993) re- cognized three subspecies of S. barbatus: the nominate subspecies from Borneo; S. b. oi from Sumatra, the Malay Peninsula, and islands of the Riau and Lingga archipelagos; S. b. ahoenobarbus from the Palawan, Balabac and Culion Islands, Philippines. Groves (2001) later suggested that S. b. ahoenobarbus should be elevated to full species. The bearded pigs from Bangka Island were named S. barbatus edmondi by Sody (1937), a subspecies that Groves (1981) rejected. New wild pig populations have been discovered recently, including a new species from Tawi Tawi Island and offshore islets (Oliver, 2001). The aim of this study was to investigate phylogenetic and systematic relationships among SEA wild pig populations using a combination of morphometric and genetic analyses. An accurate taxonomy is a fundamental