Molecular Phylogenetics and Chronometrics of Tarsiidae Based on 12S mtDNA Haplotypes: Evidence for Miocene Origins of Crown Tarsiers and Numerous Species within the Sulawesian Clade

摘要

We report new mitochondrial DNA sequence data from tarsiers sampled from several populations, including the extreme northeast and southwest of the range of the Tarsius tarsier species complex, the most extensive sampling ever reported for this taxon. Our results provide the opportunity to produce the first ever molecular chronometric analysis of Tarsiidae. These results date the age of crown tarsiers, minimally, to the middle Miocene, and each of the 3 tarsier species groups, Tarsius bancanus, T. syrichta, and the T. tarsier complex, to the early or middle Miocene. Thus, each of these 3 species has evolved in isolation for a period of time that is consistent with that which would be expected for multiple speciation events. Our analysis of the Tarsius tarsier complex reveals 5 subclades, each of which is interpreted to represent a haplogroup at, or above, the species level, a result that is consistent with current hypotheses about numerous cryptic species within this species complex. The implications for conservation within the Sulawesi biogeographic region are that Sulawesi is subdivided into numerous subregions of endemism and that, by extrapolating the example of cryptic tarsier species to other taxa, biodiversity may be underestimated by an order of magnitude. The practical realties of conservation in Sulawesi are such that it is most reasonable to assume that anthropogenic extinctions are occurring, and that some species will go extinct before they have even been identified.