Researchers have described a new-to-science species of carnivorous plant that’s known from only three locations on the Philippines’ Palawan Island. The newly described pitcher plant, which grows on very difficult-to-access vertical limestone walls, may already be critically endangered given its extremely restricted range and tiny population, the researchers say in a recent study.
Nepenthes is a group of tropical carnivorous plants found in South and Southeast Asia, Madagascar, and parts of Australia. Their leaves are modified into specialized pitchers that function as slippery, passive traps: small prey like insects fall into a fluid at the base of the trap, where enzymes liquidize them for the plant to consume.
Researchers have named the newly described species Nepenthes megastoma, its species name meaning “large mouth,” referring to the pitcher’s large opening.
Ecologists first spotted a few individuals of the plant with binoculars in 2013. The plants were hanging off the vertical face of a limestone cliff within the Mount Saint Paul karst formation of Puerto Princesa Subterranean River National Park (PPSRNP) on Palawan island. At the time, they thought these were specimens of N. campanulata, a pitcher plant native to Borneo.
However, thanks to a local nature guide, researchers were made aware of another, more-accessible location where the same pitcher plant seemed to be growing. A few expeditions and drone surveys later, the researchers were able to study the plant’s morphology and ecology, eventually confirming that the species was new to science.
So far, N. megastoma is only known from three locations within PPSRNP, where it grows on steep cliff walls. The scientists could access only two of these locations, they write. In those locations, they estimated there were about 25 individual plants.
While the researchers say they can’t rule out the presence of additional populations of N. megastoma, they suggest categorizing the species as critically endangered on the IUCN Red List, given its limited distribution and small population.
The species’ small area of occurrence also puts it at risk from sudden events like fire or typhoons, the authors write. The clearing of forest for agriculture and development around PPSRNP poses another risk.
“It’s amazing that these plants have evolved to survive in such difficult and inaccessible conditions,” John Charles Altomonte, study co-author from the nonprofit Philippine Taxonomic Initiative, said in a statement. “And yet, despite their hardiness, their existence is threatened by human activity — directly by way of encroachment and poaching, and indirectly through the effects of anthropogenic climate change.”
Banner image: Photos of Nepenthes megastoma, a newly described critically endangered species endemic to Palawan in the Philippines, showing its lower pitcher (a) and two distinct variant forms of its upper pitcher (b-c). Image courtesy of Altomonte et al., 2025 (CC BY-NC-ND)
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