Typhloperipatus williamsoni was spotted in the Siang Valley in Arunachal Pradesh.
| Photo Credit: Special Arrangement
A team of researchers at the Ashoka Trust for Research in Ecology and The Environment (ATREE) had reported rediscovering a long-lost species of the velvet worms (phylum Onychophora), one of the oldest living fossils in the world, after 111 years.
Named Typhloperipatus williamsoni, the ancient species — estimated to be around 220 million years old — was spotted by the team in the Siang Valley in Arunachal Pradesh and the rediscovery was published in the Journal of Natural History. The study provides the first molecular data for the species.
Tracing the colonial trails
According to the paper, T. williamsoni was first collected during the “Abor expedition” by Stanley Kemp, the erstwhile superintendent of the Indian Museum, Calcutta, and his team in December 1911 in Siang Valley. Since Kemp’s discovery, there has been no documented records of it from India.
The specimens were spotted under stones while looking for ants in pre-monsoon season.
| Photo Credit:
Special Arrangement
Between 2021 and 2023, the ATREE team comprising Surya Narayanan, D.R. Priyadarsanan, A.P. Ranjith, R. Sahanashree and Aravind Neelavar Ananthram, along with the National Geographic Society and Fellis Creation, followed the trails of the Abor expedition. This time, the researchers found two individuals of T. williamsoni for the first time since its description. Interestingly, the specimens were spotted under stones while looking for ants in pre-monsoon season.
Living fossils
“Onycophora is a very old group, easily older than 350 million years. It has only two families and not more than 200 species. The diversity is very less,” explained Mr. Narayanan, lead authour of the paper.
“These were evolving almost simultaneously with dinosaurs. When the mass extinction happened, probably a lot of them were wiped out. What we see today is mostly those species which escaped extinction.”
The rediscovery of T. williamsoni, which was thought of as extinct, also could help solve a biogeographic mystery, he noted.
Turning a corner
The molecular data from T. williamsoni indicated that South Asian onychophoras split from their neotropical (Central and South America including southern parts of Mexico and the Caribbean) and only African relatives around 237 million years ago.
The rediscovery of T. williamsoni, a naturally rare species, is critical in terms of addressing gaps in the evolutionary history of Asian peripatids.
| Photo Credit:
Special Arrangement
Interestingly, the Asian onycophora were found to have no relatives in Australian onychophoras. This is unusual given invertebrates found in Southeast Asia and India are usually related to those in Australia. Asian Onychophora is one of the few exceptions to this relationship.
“This rediscovery could actually turn the biogeographical story and could tell us more about how this one small group of animals ended up in Asia from the neotropics, which was always a puzzle,” Mr. Narayanan noted.
More species
The metallic blue ant, Paraparatrechina neela,more than 15 new species of parasitic wasps, a mollusc and a gecko are among the other published discoveries.
The metallic blue ant, Paraparatrechina neela,more than 15 new species of parasitic wasps, a mollusc and a gecko are among the other published discoveries.
| Photo Credit:
Special Arrangement
“We may take a few more years to discover all the new species we have collected in the expedition,” said Mr. Priyadarshanan, who was part of the team. He added that more expeditions will be held in the region.
While the rediscovery of T. williamsoni, a naturally rare species, is critical in terms of addressing gaps in the evolutionary history of Asian peripatids, the paper notes that its natural habitat faces significant threats from expanding agriculture, deforestation, and slash-and-burn cultivation in the Siang Valley. The study calls for the conservation of these habitats and broader sampling in the region.
Published – April 12, 2025 02:03 pm IST
