title: Boundary zone between northern and southern pig-tailed macaques and their morphological differences.
abstract: Based on previous conflicting reports that the two forms of pig-tailed macaque (northern and southern) exist as separate species, subspecies, or forms, and that their boundary zone lies in Thailand, a survey of the distribution range and morphology of pig-tailed macaques in Thailand was conducted during 2003-2010. We first conducted a questionnaire survey. Questionnaires were sent to 7,410 subdistricts throughout Thailand. We then traveled to 72 of the 123 subdistricts reporting the presence of pig-tailed macaques. However, due to a lack of reports of the presence of free-ranging pig-tailed macaques living south of the Isthmus of Kra, a survey of pet pig-tailed macaques was also conducted during 16-24 September 2011. Furthermore, 35 wild northern pig-tailed macaques inhabiting northern Thailand (13°13'N, 101°03'E) were temporarily caught and their morphological characters were measured and then compared to those of the southern form captured from Sumatra, Indonesia. Although largely allopatric, the ranges of the northern and southern pig-tailed macaques in Thailand were found to have a partially sympatric boundary at the Surat Thani-Krabi depression (8-9°30'N). Morphologically, these two forms were very distinctive, with different morphological characters such as the crown patch, the white color of the triangle above the eyes, the red streak at the external rim of the eyes, pelage color, ischial callosity, tail length and carriage, facial height, and limb length in both sexes, and patterns of sex skin swelling and reddening in females. These differences in morphological characters between the northern and southern forms should help settle the problems of their taxonomy.
authors: Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. Suchinda.m@chula.ac.th
authors: Suchinda
authors: S
authors: Malaivijitnond
authors: Visit
authors: V
authors: Arsaithamkul
authors: Hiroyuki
authors: H
authors: Tanaka
authors: Porrawee
authors: P
authors: Pomchote
authors: Sukanya
authors: S
authors: Jaroenporn
authors: Bambang
authors: B
authors: Suryobroto
authors: Yuzuru
authors: Y
authors: Hamada
mesh_terms: D063147:Animal Distribution; D000818:Animals; D005260:Female; D007214:Indonesia; D008254:Macaca nemestrina / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology*; D008297:Male; D013045:Species Specificity; D013785:Thailand