Ventral pelage variation of the endangered colobine monkey Javan fuscous langur Presbytis comata fredericae Sody, 1930

Presbytis comata sensu stricto is an endemic langur from Java inhabiting the hill land to the upland forest in the west, central, and few regions in the east part of the Java Island. This species inhabits the 33 sites in Java with an endangered status as according to the IUCN. The ‘sensu stricto’ means that this species may be classified differently. Some authors agreed that they fall into two separated species, while others prefer to keep it as one species with two subspecies categories. Without attempting to intervene in the classification polemic, this paper aims at presenting the variation of the ventral pelage coloration of the langur. This paper stand on the descriptive analysis. We analyzed 11 photos representing 11 different individuals from Petungkriyono (the western part of the Dieng Mountains) and Mount Merbabu. We also analyzed four videos from both research sites and one taxidermic individual specimen from Mount Merbabu. There are five types of ventral coloration of Presbytis comata fredericae found in Central Java. The ventral coloration of the newly found langur of Merbabu resembles the Presbytis comata fredericae identified from Mount Slamet. Generally, langurs of Mount Merbabu have a black or dark gray color on the dorsal side and broader bright white hair color on the ventral side. The bright white in the ventral side differs Mount Merbabu's langur from its conspecific of the Dieng Mountains. However, individuals with fuscous tail tips are commonly found in the Dieng Mountains and absent in Mount Merbabu.