Biodiversity of the Buffalo Leeches Genus Hirudinaria (Arhynchobdellida, Hirudinidae) in Southern Thailand Revealed from DNA Barcoding.

Leeches in the genus Hirudinaria Whitman, 1886, also known as buffalo leeches, are blood-sucking ectoparasites of vertebrates. Although they are widely distributed in Asia and had been highly abundant in the past, studies on diversity and taxonomy of this genus are still scarce. There is probably a large amount of cryptic diversity yet to be discovered, particularly from mainland Southeast Asia. In this study, we used morphology and DNA barcoding with a COI gene fragment to explored the diversity of Hirudinaria leeches in the southern region of Thailand, where a unique geographic feature could have led to the diversification of freshwater biota. Molecular phylogenetic analyses and species delimitation approaches (ABGD, bPTP, GMYC, and BOLD) revealed the presence of four putative species of Hirudinaria leeches from southern Thailand, including H. bpling, H. thailandica, and two morphologically cryptic lineages of H. manillensis. Compared to other leech genera, genetic distances of Hirudinaria leeches were relatively low (0.11-0.65% within species; 3.72-14.36% between species) and barcoding gaps were very narrow (1.54-2.88%). The species diversity, distribution pattern, and a phenomenon of low genetic divergence of Hirudinaria leeches in southern Thailand could be explained by an ancient seaway, paleo-drainage, and anthropogenic activities.

Genetic analysis of hybridization between white-handed (Hylobates lar) and pileated (Hylobates pileatus) gibbons in a contact zone in Khao Yai National Park, Thailand.

Natural hybridization has played various roles in the evolutionary history of primates. Its consequences range from genetic introgression between taxa, formation of hybrid zones, and formation of new lineages. Hylobates lar, the white-handed gibbon, and Hylobates pileatus, the pileated gibbon, are largely allopatric species in Southeast Asia with a narrow contact zone in Khao Yai National Park, Thailand, which contains both parental types and hybrids. Hybrid individuals in the zone are recognizable by their intermediate pelage and vocal patterns, but have not been analyzed genetically. We analyzed mitochondrial and microsatellite DNA of 52 individuals to estimate the relative genetic contributions of the parental species to each individual, and the amount of introgression into the parental species. We obtained fecal samples from 33 H. lar, 15 H. pileatus and four phenotypically intermediate individuals in the contact zone. Both mitochondrial and microsatellite markers confirmed distinct differences between these taxa. Both H. lar and H. pileatus contributed to the maternal lineages of the hybrids based on mitochondrial analysis; hybrids were viable and present in socially normal reproductive pairs. The microsatellite analysis identified ten admixed individuals, four F1 hybrids, which corresponded to phenotypic hybrids, and six H. lar-like backcrosses. All 15 H. pileatus samples were identified as originating from genetically H. pileatus individuals with no H. lar admixture; hence, backcrossing is biased toward H. lar. A relatively low number of phenotypic hybrids and backcrossed individuals along with a high number of parental types indicates a bimodal hybrid zone, which suggests relatively strong bias in mate selection between the species.

Phylogeography and ecological niche modeling reveal evolutionary history of Leiolepis ocellata (Squamata, Leiolepidae).

Leiolepis ocellata is a lizard species distributing in topographically diverse habitats in northern Thailand. To explore its evolutionary history, 113 samples of L. ocellata were collected from 11 localities covering its distributional range in northern Thailand, and sequenced for mtDNA fragments (Cyt b and ND2). Pairwise comparisons across sampling localities yielded significant genetic differentiation (F ST and Jost's D) but no clear pattern of isolation by distance could be demonstrated based on the Mantel test. Phylogenetic and network analyses highlighted six haplogroups. Their divergence times were estimated to occur during the Pleistocene, much more recent than major orogenic events affecting northern Thailand. Instead, the results suggested that lineage divergences, of particularly eastern and western haplogroups of the region, coincided with the major rivers in the region (Yom river and Ping river, respectively), indicating vicariance in response to riverine barriers. Furthermore, ecological niche modeling suggested an expansion of suitable habitats of L. ocellata, when LGM-liked conditions. This expansion potentially facilitated their dispersal among adjacent localities leading to lineage diversification and genetic admixture, after the riverine divergence.

Species Identification and Unlocking Hidden Genetic Diversity of Confiscated Slow Lorises (Nycticebus spp.) Based on Mitochondrial DNA Markers.

Confiscated slow lorises (Nycticebus spp.) at Bangpra Water-Bird Breeding Center (BWBC) in Thailand provided an opportunity to demonstrate the application of noninvasive genetic approaches for species identification when morphology of the animals was ambiguous. The slow lorises at BWBC had been assigned to either N. bengalensis or N. pygmaeus, based on body size. However, the morphology of N. bengalensis is highly variable and overlaps with that of N. coucang (sensu stricto). Phylogenetic analysis of cytochrome b and d-loop mitochondrial regions placed all confiscated N. pygmaeus with the published sequences of N. pygmaeus and distinguished them from other Nycticebus. All other confiscated individuals formed a monophyletic clade, most individuals grouping with published N. bengalensis sequences from wild populations in Vietnam and distinct from Peninsular Malaysian and Sumatran N. coucang, Javan N. javanicus and Bornean N. menagensis. Six individuals within the N. bengalensis clade formed a separate subgroup that did not group with any reference material as indicated by phylogenetic and haplotype network analyses. Whether these trafficked individuals are undiscovered wild populations will require further investigation. Additional genetic studies of wild slow loris populations in different regions are therefore urgently required for reference to aid the protection and conservation of these threatened species.

Abnormal Repetitive Behaviours of Confiscated Slow Loris (Nycticebus spp.) in Thailand.

The illegal wildlife trade, especially of live animals, is a major threat to slow lorises. Large numbers of confiscated slow lorises are sent to rescue facilities. We aimed to describe the occurrence and types of abnormal repetitive behaviours (ARBs) in 36 confiscated Bengal slow lorises (Nycticebus bengalensis), and examined factors influencing the occurrence of ARBs. We recorded behaviours of the slow lorises using instantaneous scans every 5 min from 19: 00 to 06: 00 h, and observed 6 types of ARBs in 14 (38.9%) individuals. Each individual exhibited 1 type of ARB. The most prevalent ARBs were pacing, rocking and up-down movement, and represented 29.9 ± 13.6% of the activity budget. Sex did not significantly influence the occurrence of ARB. Animals who had been at the centre for longer had a greater tendency to exhibit ARBs, but this was not statistically significant. We suggest that housing slow lorises in large semi-natural enclosures with conspecifics may reduce ARBs. Other factors potentially influencing ARBs, such as cage size, should be further investigated.

The ecology of white-handed and pileated gibbons in a zone of overlap and hybridization in Thailand.

OBJECTIVES: The study of related species in contact zones can elucidate what factors mediate species coexistence and geographical distributions. We investigated niche overlap and group interactions of two gibbon species and their hybrids co-occurring in a zone of overlap and hybridization. METHODS: The location, composition and behavior of white-handed, pileated, and mixed-species gibbon groups were studied by following them during 31 consecutive months in a relatively large part of the contact zone. RESULTS: Twenty groups of white-handed gibbon were mapped followed by nine groups of pileated gibbons and five mixed-species groups. White-handed, pileated and mixed-species groups had similar sizes and composition, ate a high proportion of fruits, shared a large number of species in their diets, and presented similar habitat preferences. Group home range sizes did not differ between species and overlapped little with neighboring groups irrespective of species, and intraspecific and interspecific encounter rates were similar. DISCUSSION: Ecological similarities support that competition between the gibbon species exists and takes the form of interspecific territoriality. However, we could not find any clear mechanism of niche partitioning favoring coexistence between species. Our findings suggest that the contact zone is unstable and is maintained by dispersal inward from groups of the parental species. The relatively low numbers of mixed-species groups and hybrids found suggests a high degree of premating reproductive isolation, perhaps mediated by interspecific miscommunication. The existence of hybrids and backcrosses potentially undetectable from phenotypic characters alone raises the possibility of more widespread introgression than has been evident. Hence, while interspecific territoriality should reduce the rate of gene transfer, it would not necessarily present a barrier to introgression into contiguous populations of the opposite species.