Chordates • Earth.com

Dusky leaf monkey

(Trachypithecus obscurus)

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Description

The dusky leaf monkey, spectacled langur, or spectacled leaf monkey (Trachypithecus obscurus) is a species of primate in the family Cercopithecidae. It is found in Peninsular Malaysia, Myanmar and Thailand; however, dusky leaf monkeys have occasionally been observed in Singapore. It is not clear whether these monkeys are escaped pets or whether they swam to Singapore on their own volition from Johor, Malaysia Research in Malaysia found the dusky leaf monkey spends 40% of the day positioning, 33% feeding, 20% moving, and the rest of the time allogrooming (4%), playing (2%), and foraging (1%). It tends to consume leaves growing at higher elevations in the forest canopy.Fruit availability is season-dependent, and although the dusky leaf monkey in Malaysia eats 51% leaves and 40% fruits, it prefers to eat fruit when it is available. The lutungs, langurs, or leaf monkeys are a group of Old World monkeys in the genus Trachypithecus (derived from Greek τραχύς, trachýs meaning "rough" and πίθηκος, píthekos meaning "monkey"). Their range is much of Southeast Asia (northeast India, southern China, Borneo, Thailand, Java, and Bali). The name "lutung" comes from the Sundanese language and means "blackness"; it is preferred in one paper because the authors wanted the name langurs to only refer to monkeys in the genus Semnopithecus,although some "lutungs" are now "langurs" again. Genetic analysis indicates that the ancestors of the modern species of lutung first differentiated from one another a little over 3 million years ago, during the late Pliocene. The various species alive today then diverged during the Pleistocene, presumably driven by habitat changes during the Ice Ages. The oldest fossils clearly identified as belonging to the genus date from the middle Pleistocene of Vietnam and Laos; later fossils are also known from Thailand, Java, and Sumatra. The closest living relatives of the lutungs are probably either the gray langurs or the surilis, although the exact relationships remain unclear, possibly due to hybridisation between these genera during the course of their recent evolutionary history. Lutungs have a rather slim build with a long tail. The fur color varies, depending on the species, from black and grey to orange yellow. Many species have skin designs and a brighter lower surface, the hair on the head is often compared to a hood. Their arms are very short in comparison to the feet and their thumbs are also somewhat shorter.

Taxonomic tree:

Domain:
Kingdom: Animalia
Phylum:
Class: Mammalia
Order:Primates
Family:Cercopithecidae
Genus:Trachypithecus
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