Dr Jean Boubli and PhD student Hazel Byrne, working with zoologists from Brazil and the US, used cutting-edge molecular and computer modelling techniques to investigate the genus Callicebus, first described by Oldfield Thomas in 1903.
Published on 1 March in the journal Frontiers in Zoology, the research identifies much greater diversity in the titi which they propose to redefine as three distinct genera — Callicebus (Titi), Cheracebus and Plecturocebus. They have also reclassified the species Callicebus dubius as Callicebus caligatus, reducing the number of recognised species from 34 to 33.
Jean Boubli described the findings as the “culmination of his 20 year quest for the origins of titi monkey diversity”.
Decades of samples
Jean Boubli, who spent three years with the Yanomami peoples in the northern Amazon, and Hazel who also spent months in the jungle, built the largest array of titi monkey DNA sequences ever assembled, affording a fresh perspective on the key evolutionary events and when they occurred over time.
They pinpoint the split between Plecturocebus and Callicebus at approximately 11 million years ago and the split of Callicebus and Cheracebus to 8 million years.
“Historically taxonomy (the classification of animals) has been largely based on morphology — colour, shape, size, features — rather than genetic diversity. However, things can be very closely related and look quite different, or be genetically distinct and look the same,” explained Hazel Byrne.
Illustration by Stephen D. Nash ©Conservation International.
So does it matter?
“Absolutely”, says Jean Boubli who describes taxonomy as “the road map of conservation” and ultimately, our understanding of how the evolutionary tree of primates fits together, guides decisions about which groups are endangered and which need protection. “Each of the three genera can now be recognised as unique, important lineages, giving governments and NGOs a clearer focus for conservation programmes. “It makes sense that before you say ‘we’re going to dedicate our resources to this, you need to know what ‘this’ is.”
The team are following up the research with a forthcoming biogeographical analysis, investigating how these genera diversified over time and space, which could shed light on how the Amazon was formed.
(Source: University of Salford — Manchester news release, 06.04.2016)