DistributionRead full entry
Range DescriptionThe distribution limits of this species are unknown, reflecting ambiguity over what the name refers to, and how to identify taxa within the M. rooseveltorum complex. For a description of the range of this species-complex see M. rooseveltorum. The syntypes of M. truongsonensis were collected from four houses in three locations in Hien District, west Quang Nam Province, Viet Nam. The three locations are: Hien, the district capital, A Tin village, and A Plo village (1556'59''N, 10734'18''E) (P.M. Giao et al. 1998). Two skulls which share the distinctive mtDNA sequences presented by P.M. Giao et al. (1998) for M. truongsonensis were collected in the adjacent area of Lao PDR, on the Dakchung Plateau (Amato et al. 1999b, 2000; R.J. Timmins pers. comm. 2008). Published range descriptions for M. truongsonensis (e.g. Groves and Schaller 2000; Grubb 2005) are hypothetical. Specimens and camera-trap photographs of animals of the M. rooseveltorum complex, but morphologically dissimilar to the M. rooseveltorum holotype (see taxonomic note) occur from the type locality of M. truongsonensis north to at least the northern highlands of Lao PDR and Viet Nam and probably into adjacent areas of China (R.J. Timmins pers. comm. 2008). M. truongsonensis may be found to occur throughout the range of the M. rooseveltorum species-complex (dark-pelaged animals appear to be widespread), but equally it could be much more localised.
Circumstantial evidence from Myanmar presents a possibility of more than one taxon in the M. rooseveltorum species complex in that region (see 2008 Red List account for M. putaoensis), with potentially similar pelage and skull character variation as shown in Indochina. Amato et al. (1999a, 1999b, 2000) placed M. putaoensis as the sister taxon to M. truongsonensis on the basis of mtDNA, and the holotype of the former species shares with specimens speculated to be M. truongsonensis long premaxillae that contact the nasals; in fact skulls of these two taxa may be (nearly) impossible to diagnose apart (R.J. Timmins pers. comm. 2008). Some uncertainty exists over the pelage characteristics of M. putaoensis, although the assumption is that they are reddish animals (see 2008 Red List account for M. putaoensis). Contrary to the statements of Rabinowitz et al. (1999) and others, which have not taken into account the patchiness of suitable surveying, the small muntjacs comprising the M. rooseveltorum species-complex are not particularly restricted in range, but are rather widespread in montane areas of northern southeast Asia. The lack of evidence of the complex from many areas, giving an apparent disjunct distribution, is much more likely to reflect the paucity of suitable surveys than the genuine distribution pattern. Survey work in south-west and south-east China, much of Myanmar, the Himalayan region and northern and western Thailand have certainly been insufficient to conclude anything about the range of this species-complex in those regions.
Grubb (2005) suggested that various muntjac specimens recorded from China (in Sokolov 1957; Shou 1962) might be attributable to M. truongsonensis, without giving profound justification. It seems, on current knowledge, equally likely that they belong elsewhere in the M. rooseveltorum species-complex, or, as suggested by the original authors, that they refer to animals from the M. crinifrons species-complex (i.e. that species, M. feae and M. gongshanensis).