Carnivorous plant discovered in Palawan, but already on brink of extinction

December 28, 2025 | 3:31pm

MANILA, Philippines — Philippine scientists have confirmed the discovery of a previously unknown species of carnivorous tropical pitcher plant found only on the limestone cliffs of Palawan, a rare scientific milestone that has come with an urgent warning: the species is already critically endangered.

The plant, Nepenthes megastoma, was formally described in November in the international journal Phytotaxa following years of fieldwork by researchers from Ateneo de Manila University and an Australian botanical expert. It has so far been documented in just three locations inside the Puerto Princesa Subterranean River National Park.

Ecologists first noticed the plant in 2013 while surveying the park’s karst formations—a type of landscape shaped from eroded limestone—but initially mistook it for a related species found in Borneo.

Its true identity only became clear after extensive drone surveys, long-range photography, and close morphological comparison confirmed it as a previously undescribed Philippine species.

The delay was largely due to where the plant grows. N. megastoma clings to steep, exposed limestone cliffs that are difficult and often dangerous to access, forcing researchers to rely on aerial imaging before limited ground verification could be carried out.

Surviving on cliffs

Despite its harsh environment, the species shows distinctive adaptations that allow it to survive on vertical rock faces. Researchers documented upward-facing female flowers, a trait believed to aid pollination in cliffside conditions, as well as fine hairs that help trap moisture.

The plant’s pitchers also change shape with the seasons, shifting between wider and narrower forms, an adaptation the researchers say may help regulate water retention during dry periods.

“It’s amazing that these plants have evolved to survive in such difficult and inaccessible conditions,” John Charles Altomonte, one of the authors of the study, said. 

Fewer than 50 plants remain

Those adaptations, however, have not protected the species from mounting threats. Field surveys estimate that fewer than 50 mature specimens exist, clustered in fewer than 20 clumps, with only a small number of juvenile plants recorded.

Several mature plants were found damaged or dislodged from cliff walls, which the researchers linked to increasingly intense typhoons and prolonged dry spells. The study classifies N. megastoma as Critically Endangered under International Union for Conservation of Nature guidelines.

Human activity has further compounded the risk. Although the species grows within a protected area, researchers cited encroachment in surrounding areas and evidence of poaching, with illegally collected specimens reportedly already appearing in Metro Manila.

Despite the plant's "hardiness," Altomonte said, its existence is threatened directly by human activity and indirectly through "effects of anthropgenic climate change."

Alongside Altomonte, scientists studying N. megastoma are Vernaluz Mangussad, Rene Alfred Anton Bustamante, and Alastair S. Robinson.