The Sarawak surili is a species of primate

Primate

A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...

 in the Cercopithecidae family. It is endemic to the southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

n island of Borneo

Borneo

Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

, where it is distributed north of the Kapuas River

Kapuas River

The Kapuas River is a river in the Indonesian part of Borneo island, at the geographic center of Maritime Southeast Asia. At in length, it is the longest river of Indonesia and one of the world's longest island rivers...

 in Kalimantan

Kalimantan

In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....

, Indonesia

Indonesia

Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

, the Malaysia states of Sarawak

Sarawak

Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...

 and Sabah

Sabah

Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...

, and in Brunei

Brunei

Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...

. Its taxonomy

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 is complex and disputed, and it has been considered a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of P. femoralis

Banded Surili

The banded surili is a species of primate in the Cercopithecidae family. It is endemic to the Thai-Malay Peninsula and the Indonesia island of Sumatra. It is threatened by habitat loss. Three subspecies, femoralis , robinsoni and percura, are recognized here, but the taxonomy is complex and...

or P. melalophos

Sumatran Surili

The Sumatran surili is a species of primate in the Cercopithecidae family. It is endemic to Sumatra in Indonesia. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss.-External links:...

. The Sarawak Surili was formerly considered common, but has declined drastically due to persecution and habitat loss, and as of 2008 is only known from five sites with a combined population of 200–500 individuals. Consequently, it is believed to be one of the rarest primates in the world, and has been rated as Critically Endangered

Critically Endangered

Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....

 by IUCN.