Actephila alanbakeri (Phyllanthaceae): a new nickel hyperaccumulating plant species from localised ultramafic outcrops in Sabah (Malaysia)

The Malaysian state of Sabah on the Island of Borneo is emerging as a hotspot for nickel hyperaccumulator species with at least 25 such species discovered to date. New discoveries of the hyperaccumulation trait in described taxa, as well as taxonomical novelties that are nickel hyperaccumulators, continue to be made. Here we describe a new nickel hyperaccumulating species of Actephila (Phyllanthaceae) originating from two known populations on ultramafic soils in Sabah. The most characteristic feature of Actephila alanbakeri are its knobbly fruits, but other diagnostic morphological characters are discussed and information about its ecology and rhizosphere and plant tissue chemistry is provided. This new species is one of the strongest known nickel hyperaccumulator plants in Southeast Asia with up to 14,700 μg g(-1) (1.47 %) nickel in its leaves. The occurrences of Actephila alanbakeri on just two sites, both of which lie outside protected areas and are disturbed by recurring forest fires, combined with the small total numbers of individuals, render this species Endangered (EN) on the basis of IUCN Red List Criteria.