抄録
Rhesus macaques inhabiting Indochinese Peninsula, especially the “boundary zone” lying approximately 15-20°N, are supposed to be hybrids between pure rhesus and long-tailed macaques, as shown by the longer tail (50-60 % of Head & Trunk Length; Fooden, 2000) or by the sequence of mtDNA and TSPY gene (Tosi et al., 2003). However, the determination of morphological and genetic characters by on-site samplings from local populations has never been done. We carried out catch-&-release survey on three rhesus troops inhabiting northeastern Thailand (N 16° 27’ – 18°30’), Wat Tham Pa Mak Ho (WTPMH), Ban Sang School (BSS), and Wat Pattanajit (WPT). Comparative data were rhesus (Chinese origin, CH) and long-tailed macaques (lower northern Thailand, TH). Rhesus macaques of CH are the largest in body mass (BM) and crown-rump length (CRL), and the size order in percentage of CH is from WTPMH, WPT, BSS to TH (BM: 82, 61, 57 and 60%, CRL: 87, 85, 81 and 80%, respectively). Relative tail length against CRL (%) varies widely from CH (36.5%), WTPMH (53.9%), WPT (64.7%), BSS (69.4%), to TH (112.5%). The pelage color also varies widely as shown by the contrast (difference) of red-green hue (b*) between the back and waist. The so-called bipartite pattern was found in CH (4.79) and WTPMH (6.37), but was not in TH (1.48). BSS (3.98) and WPT (2.63) were intermediate. Analysis of mtDNA offered intriguing results, that is, BSS and WPT had a “mulatta type” as CH, but WTPMH had a “fascicularis type” as TH. Interestingly, only the “mulatta type” of TSPY gene was found in five groups compared. Our morphological and genetic analysis suggested more or less of the introgression between rhesus and long-tailed macaques inhabiting northeastern Thailand. The degree and manner of gene-flow are of importance for the elucidation of evolution of these two species.
