Propithecus deckenii, Peters, 1870

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Indriidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 142-175 : 169-170

11.

Decken’s Sitaka

Propithecus deckenii

French: Sifaka de der Decken / German: Von-der-Decken-Sifaka / Spanish: Sifaca de Decken

Other common names: Von der Decken’s Sifaka

Taxonomy. Propithecus deckenii Peters, 1870 ,

Madagascar, Kanatsy.

Some experts consider this species to be synonymous with P. coronatus . To the north in the coastal forests between the Mahavavy and Betsiboka rivers, the geographic separation between P. deckenii and P. coronatus appears clear, but in the upper reaches of the Mahavavy River, populations of the two species apparently hybridize, and there are individuals with intermediate coloration on islands in the middle of the Mahavavy. More confusing is the situation in the forests of the Bongolava Massif, far inland and to the south-east, where individuals with color patterns characteristic of both species have been observed. Furthermore, according to fairly recent surveys, populations representing both species can be found at a number ofsites. Needless to say, the taxonomic status of these two forms and their relationship to one another require further investigation, especially in the field. Monotypic.

Distribution. CW Madagascar, found mainly between the Manambolo and Mahavavy rivers, the S limit of its distribution does not extend to the Tsiribihina River (which marks the N limit of Verreaux’s Sifaka, P. verreauxi ). This species and the Crowned Sifaka (PF. coronatus ) are often found in the same areas, although the latter tends to be found further inland than the more coastal Decken’s Sifaka.

Descriptive notes. Head-body 42-48 cm, tail 50-60 cm; weight 2:6.2-9 kg. Decken’s Sifaka is a small species of Propithecus . The dorsal coat is creamy-white, often with faded silvery, golden, or pale brown tints on the neck, shoulders, back, and limbs. Some individuals have dark areas on the head and chest. The face is naked and black, although usually with a patch of white fur running across it. Bony pockets on either side of the muzzle give Decken’s Sifaka a rather blunt-nosed appearance, but not as extreme as in the Crowned Sifaka.

Habitat. Dry deciduous forest patches. Decken’s Sifaka seems to be fairly resilient to habitat degradation, and individuals have even been observed in Eucalyptus (Myrtaceae) trees in the middle of Soalala town.

Food and Feeding. There is no information available for this species.

Breeding. There is no information available for this species.

Activity patterns. There is no specific information available for this species, but Decken’s Sifaka is diurnal and mainly arboreal.

Movements, Home range and Social organization. There is no specific information available for this species, but it is believed to occur in groups of 2—10 individuals.

Status and Conservation. CITES Appendix I. Classified as Vulnerable on The IUCN Red List. However, at the IUCN/SSC Lemur Red-Listing Workshop in July 2012, P. decken was assessed as endangered. Forests in the distribution of Decken’s Sifaka are already highly fragmented, and continued habitat loss is the greatest threat to its survival. Habitat is burned to provide pasture for livestock and cut for charcoal production. Hunting is rare because Decken’s Sifaka is protected by a very strong taboo over much of its range, leading them to become very tame. Nevertheless, if the taboo were to break down for whatever reason, Decken’s Sifaka could disappear very rapidly. It occurs in three national parks (Baie de Baly, Tsingy de Bemaraha, and Tsingy de Namoroka), Tsingy de Bemaraha Strict Nature Reserve, and four special reserves (Ambohijanahary, Bemarivo, Kasijy, and Maningoza). It is also found in at least one classified forest (Tsiombikibo), which provides some degree of protection.

Bibliography. Curtis et al. (1998), Garbutt (2007), Hawkins et al. (1998), Mittermeier et al. (2010), Nicoll & Langrand (1989), Petter & Peyrieras (1972), Petter et al. (1977), Randrianarisoa, Rasamison & Rakotozafy (2000, 2001), Rumpler et al. (2011), Tattersall (1982, 1986a, 1986b), Thalmann & Rakotoarison (1994), Thalmann, Kimmerli & Zaramody (2002), Thalmann, Mller et al. (1999).

Figures

On following pages: 12. Crowned Sifaka (Propithecus coronatus); 13. Coquerel’s Sifaka (Propithecus coquerell); 14. Tattersall’s Sifaka (Propithecus tattersall); 15. Diademed Sifaka (Propithecus diadema); 16. Milne-Edwards's Sifaka (Propithecus edwardsi); 17. Silky Sifaka (Propithecus candidus); 18. Perrier’s Sifaka (Propithecus perrieri).

Distribution. CW Madagascar, found mainly between the Manambolo and Mahavavy rivers, the S limit of its distribution does not extend to the Tsiribihina River (which marks the N limit of Verreaux’s Sifaka, P. verreauxi ). This species and the Crowned Sifaka (PF. coronatus ) are often found in the same areas, although the latter tends to be found further inland than the more coastal Decken’s Sifaka.