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Sabah's hidden giant: Nepenthes pongoides (Nepenthaceae), a micro-endemic tropical pitcher plant from northern Borneo.

Alviana Damit, Nur Adillah Yusof, Jemson Jumian, Charles Clarke, Alastair Robinson

Abstract

Context: A poorly characterised carnivorous tropical pitcher plant (Nepenthes) was identified from old reports of a rarely visited low-elevation ultramafic peak in central Sabah, Malaysian Borneo. Potentially apomorphic characters in the limited photographic evidence available led the authors to hypothesise that the taxon represented an undescribed species. Aims: To locate and document the unknown taxon in situ and, if appropriate, gather sufficient data and voucher material to enable its formal description and associated conservation status assessment. Methods: An expedition was made to the type locality to make field observations of the taxon, record habitat, population, and ecological data, such as infauna, prey spectra and numbers of individuals, and to collect representative vouchers, minimising negative impacts on the small population by taking material in the form of terminal cuttings to allow for the in situ regeneration of sampled individuals from axillary nodes. Key results: Nepenthes pongoides is described and illustrated as new to science. It is characterised by its large size, peltate tendril exsertion, absence of upper pitchers, and extremely well-developed, persistent indumentum of long, coarse, dark reddish trichomes, the extent of which is unsurpassed in any other known Bornean Nepenthes species. Conclusions: One of the largest species of Nepenthes described in recent years, N. pongoides is endemic to the relatively low-elevation ultramafic Meliau Range of central Sabah. With just 39 mature individuals observed across two subpopulations, it is here assessed as CR (Critically Endangered) under the IUCN Red List criteria owing to its extremely small population size, limited area of occurrence, and the very high threat of unsustainable poaching for the horticultural trade. Like many microendemic species, the taxon is extremely vulnerable to stochastic events like fires which, on sufficient scale, could represent extinction level events. Implications: The documentation of such remarkable new species in comparatively well-explored rainforest regions like those of northern Borneo highlights the importance of targeted exploration in remaining wilderness areas to uncover hidden biodiversity. Doing so closes gaps in scientific knowledge, and specifically increases the critical taxonomic and ecological knowledge necessary to support the development and implementation of conservation measures required to reduce the risk of species extinction and concomitant loss of biodiversity.

BT24050  Accepted 18 November 2024

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