Genetic variability within and between the troops of toque macaque,Macaca sinica, in Sri Lanka

What makes a long tail short? Testing Allen's rule in the toque macaques of Sri Lanka

Allen's rule (1877) predicts ecogeographical anatomical variation in appendage proportions as a function of body temperature regulation. This phenomenon has been tested in a variety of animal species. In macaques, relative tail length (RTL) is one of the most frequently measured appendages to test Allen's rule. These studies have relied on museum specimens or the invasive and time-consuming capturing of free-ranging individuals. To augment sample size and lessen these logistical limitations, we designed and validated a novel noninvasive technique using digitalized photographs processed using LibreCAD, an open-source 2D-computer-aided design (CAD) application. This was used to generate pixelated measurements to calculate an RTL equivalent, the Tail to Trunk Index (TTI) = (tail [tail base to anterior tip] pixel count/trunk [neck to tail base] pixel count). The TTI of 259 adult free-ranging toque macaques (Macaca sinica) from 36 locations between 7 and 2,087 m above sea level (m.a.s.l.) was used in the analysis. Samples were collected from all three putative subspecies (M. s. sinica, aurifrons, and opisthomelas), at locations representing all altitudinal climatic zones where they are naturally distributed. These data were used to test whether toque macaque tail length variation across elevation follows Allen's rule, predicting that RTL decreases with increasing elevation and lower temperature. Our results strongly supported this prediction. There was also a statistically significant, negative correlation between elevation and annual average temperature. The best predictor for the TTI index was elevation. Significant subspecies differences in RTL are linked in part to their ecological and altitudinal niche separation, but overall the variation is seen as the species' adaptation to climate. The method developed for the quick morphometric assessment of relative body proportions, applicable for use on unhabituated free-ranging animals, widens the range of materials available for research studying morphological characteristics and their evolution in primates.

Isolation and Molecular Characterization of Entamoeba nuttalli Strains Showing Novel Isoenzyme Patterns from Wild Toque Macaques in Sri Lanka

We have proposed the revival of the name Entamoeba nuttalli for a virulent ameba strain, P19-061405, from a rhesus macaque and located it phylogenetically between E. histolytica and E. dispar. As E. nuttalli was originally described for an ameba found in a toque macaque in Sri Lanka, the prevalence and characteristics of Entamoeba species in wild toque macaques were examined. PCR analysis of 227 stool samples from six locations showed positive rates for E. nuttalli, E. dispar, and E. histolytica of 18.5%, 0.4%, and 0%, respectively. Fifteen E. nuttalli strains were cultured successfully from five locations. The 18S ribosomal RNA gene showed only three nucleotide differences in comparison with P19-061405 strain. In isoenzyme analysis, the pattern of hexokinase in Sri Lankan strains was different from that of P19-061405 strains and the difference was confirmed by analysis of the genes. Hepatic inoculation of one of the Sri Lankan E. nuttalli strains in hamsters resulted in amebic abscess formation and body weight loss. These results demonstrate that E. nuttalli is prevalent in wild toque macaques and that several characteristics of the strains are unique. We conclude that use of the name E. nuttalli is appropriate for the new Entamoeba species found in nonhuman primates.

The local distribution of highly divergent mitochondrial DNA haplotypes in toque macaques Macaca sinica at Polonnaruwa, Sri Lanka

Surveys of mitochondrial DNA (mtDNA) variation in macaque monkeys have revealed extremely high levels of intraspecific divergence among haplotypes. One consistent pattern that has emerged from these studies is that divergent haplotypes are geographically segregated so that sampling a few matrilines from a given region shows them to be identical, or a closely related subset of haplotypes. Geographically structured mtDNA variation has also been commonly observed in other taxa. In this study, haplotype variation and distribution are studied in detail within a local population of toque macaques. The results show that highly divergent haplotypes, differing by 3.1% in their nucleotide sequences, coexist in this population and that they may be spatially segregated even on this micro-geographic scale. Furthermore, these differences are maintained between social groups that exchange male migrants, and thus nuclear genes, frequently.