A new study published in the journal Zoological Research has uncovered a new species of primate in Myanmar after analyzing the mitochondrial DNA of the Asian colobine genus Trachypithecus. The discovery of the ghostly species, named the Popa langur (Trachypithecus popa) hinged on a 100-year-old specimen from the Natural History Museum (NHM) in London, UK. Now that the species has been defined, researchers on the study hope it will reinvigorate conservation efforts for the estimated 200 to 250 remaining individuals that are spread across four isolated groups in Myanmar.
The Popa langur is named after the sacred Mount Popa, an extinct volcano and sacred pilgrimage site that is home to around 100 langurs, making it the largest of the four populations. Throughout Myanmar, these langurs are at risk from habitat loss and hunting to the extent that the researchers have suggested the species be classified as critically endangered.
As a genus, Trachypithecus is the most species-rich and widely distributed of the Asian colobine monkeys. Much research has been done regarding the 20 known species but despite this their evolutionary history is something of a mystery. This new research wanted to combine data on the genus to paint a clearer picture of their past, and so collected samples and complete mitochondrial DNA from all 20 known species.
It was during the pursuit of a better understanding of the evolutionary history of this iconic group of primates that the new species was discovered. The differences between Trachypithecus species are subtle, mostly pertaining to fur coloration, tail length, the size of their molars, and skull shape, but genetic analyses of the NHM’s antique specimen alongside samples from other museums and extant animals established the existence of the new species.
“We analyzed 72 sequences of primates and 53 of those were from genus Trachypithecus where this new species belongs,” said Roberto Portela Miguez, senior curator in Charge of Mammals at the NHM, in an email to IFLScience. “It was after combining the results of sequencing from museum samples, fecal samples from populations collected in the wild, and a review of museum specimens that we were able to draw the conclusion that we were working with a new species.”
The study demonstrates how specimens in natural history collections can serve as valuable sources for genetic and taxonomic research as new sequencing techniques emerge that can analyze even 100-year-old DNA. The telltale T. popa specimen was collected in 1913 by Guy C. Shortridge, a British zoologist who collected thousands of specimens during the early 20th century. It's quite remarkable, then, to think that this Popa langur has enabled modern scientists to discover its taxonomic existence over 100 years later.
“This is the most comprehensive study done in this group of primates to date, so our understanding of the evolutionary history of the group and the diversity of species within has been enhanced significantly,” Miguez continued. “This piece of work could not have been done without the extraordinary enthusiasm and expertise of collaborators from all over the world, from Myanmar, Germany, Australia, US, Singapore, Vietnam, Netherlands, and more. Thanks to this extraordinary effort, we might be in time to save a species that might otherwise have been overlooked.”