Vietnam Primate Conservation Status Review 2002 - Hoang Lien ...

3.6 Indochinese Silvered langur
Trachypithecus germaini (Milne-Edwards, 1876)
3.6.1 Taxonomy
3.6 INDOCHINESE SILVERED LANGUR - Trachypithecus germaini
The taxonomy of the Silvered langur has been under debate for a long time. Milne-Edwards (1876)
described a Silvered langur for Cochin China and Cambodia as Semnopithecus germaini. Due to
similar colouration the taxa was subsequently placed by many authors as a subspecies to the Silvered
langur from Sumatra, described as Simia cristata by Raffles (1821) and later assigned to several
genera Presbytis, Semnopithecus and Trachypithecus.
Ellerman & Morrison-Scott (1951) recognize T. c. germaini as the sub-species occupying southern
Vietnam, Lao PDR and Cambodia. This nomenclature is adopted by P. Napier (1985) who argues that
specimens of T. c. germaini are generally lighter in colour, and have a different colour distribution of
hair and whiskers than the typical T. c. cristatus.
Lekagul & McNeely (1988) mention the different colouration of Silvered langurs in Thailand and
assumed three subspecies for the country.
Elliot (1909) described Presbytis margarita from the Long Bian Plateau (12 O 03’N) of Lam Dong Province,
though neither Osgood (1932), Pocock (1935) and Groves (2001) found it sufficiently different from
germaini to warrant sub-specific distinction.
Dao Van Tien (1977) described the sub-species T. c. caudalis, based on two animals of unknown
origin which had been living in Hanoi zoo. Later (undated MS) he localised the origin to Tuyen Hoa
District, Quang Binh Province (17 O 53’N) on the basis of pelage colouration. The type and paratype are
preserved in the ZMHNU. Groves (2001) accepts this subspecies and notes the similarity of these
specimens to one from Thailand in the USNM collection.
Dao Van Tien (undated MS) suggests a subspecific splitting of the species based on colour variation:
T. c. germaini in the southern lowlands, T. c. margarita on the Lang Bian Plateau and T. c. caudalis in
the central highlands up to Quang Binh. But he did not provide sufficient evidence for this splitting.
Groves (2001) assigns all the Indochinese Silvered langurs to T. germaini, reserving T. cristatus for
Sundaic forms on Borneo, Sumatra and along the west coast of the malaysian peninsula. He pointed
out that, beside different colouration and circumfacial hair structure, the length of the tail between
these two groups is markedly different.
Recent DNA analysis supports this classification and shows the diffentiation at species level (see 2.3).
However, animals recently sighted in Dak Lak Province (Ngo Van Tri, 2000), showed a particularly
dark colouration and Hoang Minh Duc (pers. comm., 2000) found populations with different colouration
in south Vietnam. Elliot (1912) mentioned already the different colouration of two animals in MNHN
Paris, both are marked as types. Despite of no marked DNA differences, the Vietnamese population
shows a wide variety in colouration or probably a polymorphism of the taxon. The related taxa
cristatus and auratus also have rather different morphs.
We propose to use the name Indochinese Silvered langur for Trachypithecus germaini.
3.6.2 Description
The colour is medium grey, caused by short creamy tips on the dark grey or brown-black hairs.
Underside, throat, and shanks creamy, grading into upper side; hands and feet black, hairs form a
creamy “bowl” around the face; tail nearly black above, lighter below.
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