New data on and the easternmost record of the Javan endemic Pearly Tree Frog, Nyctixalus margaritifer Boulenger, 1882 (Anura, Rhacophoridae)

New locality records and a range extension of the Javan endemic Pearly Tree Frog, Nyctixalus margaritifer Boulenger, 1882 are reported from Central Java and East Java. Our new data include the easternmost record in Java, a record from the eastern edge of Bromo Tengger Semeru National Park, which is approximately 142 km west of the species’ type locality in Gunung Willis in East Java. This tree-frog species inhabits undisturbed rainforest with a dense canopy and vegetation at elevations up to 1,200 m a.s.l. Based on a morphometric analysis of newly collected specimens, we found observable differences in several morphological characters. However, more specimens are needed to confirm the taxonomic status of the rare, endemic, and poorly known N. margaritifer.