Propithecus diadema, Bennett, 1832

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 : 171-172

15.

Diademed Sitaka

Propithecus diadema

French: Sifaka a diademe / German: Diademsifaka / Spanish: Sifaca de diadema

Other common names: Diademed Simpona

Taxonomy. Propithecus diadema Bennett, 1832 ,

Madagascar.

This species seems to form a clinal gradient with P. edwards: at the southern limit ofits range. A highly aberrant population, discovered in 1999 in the forests of Tsinjoarivo in south-central Madagascar, was originally believed to represent a different subspecies (marsh). It is somewhat smaller than typical P. diadema , with much longer canine teeth and different and quite variable markings (including at least one all-black individual), indicating that these animals may be a hybrid of P. diadema x P. edwards:. A preliminary genetic study did not find sufficient evidence to warrant its recognition as a new taxon, but a more recent study indicated that it is distinct. Recent molecular analysis as part of a study on the phylogenies of the Indriidae revealed two well-supported mtDNA clades in P. diadema , one of which is likely to be more closely related to P. edwards: than to the other P. diadema clade. Genetic distances between the two clades would warrant splitting the species into two taxa. Nevertheless, in the absence of data from nuclear genetic markers and with the two clades not showing any differences in their karyotypes, the authors of that study proposed male introgression as a possible cause for this paraphyly and did not delineate a new taxon. Monotypic.

Distribution. NE & E Madagascar from the Mananara River in the N to the Mangoro and Onive rivers in the S; although the precise distributional limits are unknown, the Diademed Sifaka is thought to be the most widely distributed of the sifakas, occurring throughout Madagascar’s E rainforests. Historically, its distribution extended farther N to just S of the Antainambalana River, but it has not been found in recent years during fairly extensive studies of that region.

Descriptive notes. Head—body 50-55 cm,tail 44-50 cm; weight 5.7-6.8 kg. The Diademed Sifaka is the largest of the sifakas, and it rivals the slightly larger Indri (/ndri indri ) for being the largest living prosimian. It is also one of the most colorful and attractive, with its characteristic long silky fur and prominent “diadem” fringe across the forehead. Pelage of the forehead, cheeks, and throat is white with silvery or golden tints. Shoulders and upper back are slate-gray, and the lower back lightens to silvergray. The ventral coat is typically white to pale gray. The crown is black, and this color sometimes extends to the nape. Arms and legs are orange to yellow-gold, hands and feet are black, and flanks and the tail are pale gray to white (the latter often with a golden-white base). The head is notably small and narrow. The muzzle is short, the bare face is dark gray to black, and eyes are reddish-brown. Males have a large reddishbrown cutaneous gland in the middle of their throat, and a perianal patch of similar color is also believed to be glandular. Juveniles resemble adults but they are paler, with a yellower frontal band and lighter yellow limbs.

Habitat. Primary highland rainforest at elevations of 200-1600 m, although elevations above 800 m are preferred. The Diademed Sifaka appears to require intact forest, but it can be found in small forest fragments.

Food and Feeding. Diets of the Diademed Sifaka consist mainly of ripe fruits, seeds, flowers, and young leaves; respective proportions of each vary according to seasonal abundance. Some bark also is consumed. The number ofplant species in the diet each day often reaches 25 or more, including fruits of two preferred plants whose seeds contain significant levels of alkaloids. The Diademed Sifaka eats higher energy foods compared with sympatric Indri . Individuals are reported to search and smell large areas of leaves on the forest floor to locate hidden flowers of the subterranean parasitic plants Langsdorffia (Balanophoraceae) and Cytinus (Cytinaceae) . This behavior is evidently learned by observing conspecifics.

Breeding. Females are sexually receptive for only one day per year, sometime in November—January. A single young is born in May-July, after gestation of 179 days. Infant mortality is high. Individuals may live up to 20 years in the wild.

Activity patterns. The Diademed Sifaka is diurnal and arboreal. In one study, individuals spent 49-4% of their time resting, 37-8% feeding, 2:4% in social behavior, 5-1% moving, and the remainder in other activities.

Movements, Home range and Social organization. The Diademed Sifaka has only been studied once for a significant period of time. It lives in female-dominated, multimale— multifemale groups of eight or more, consisting of 1-3 adult females and 1-2 adult males, with only one breeding pair in each group. Exclusive territories of 20-50 ha are maintained by scent marking, although there is little aggression over boundaries. Compared with the sympatric, similar-sized Indri , the Diademed Sifaka spends more time actively patrolling and defending its territories. Mean daily path of movementis 987-1629 m for the Diademed Sifaka compared to 774 m for the Indri . Males emigrate at age five to a neighboring group; females may either emigrate or remain in their natal group.

Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. However, at the IUCN/SSC Lemur Red-Listing Workshop in July 2012, P. diadema was assessed as critically endangered. The principal threat to the survival of the Diademed Sifaka is habitat loss from slash-and-burn agriculture, logging, and mining. Hunting for its meat and fur also has a very serious impact in many parts of its range, even within existing protected areas. As a result, it is now absent from many areas where it formerly occurred. It occurs in three national parks (Mananara-Nord, Mantadia, and Zahamena), two strict nature reserves (Betampona and Zahamena), three special reserves (Ambatovaky, Mangerivola, and Marotandrano), and Anjozorobe-Angavo Forest protected area. It has also been successfully reintroduced into the Analamazaotra Special Reserve at Andasibe (= Périnet), where it was extirpated 30-40 years ago. The reintroduction, carried out by E. Louis Jr. and a team of Malagasy researchers, took place in 2007 with individuals rescued from the nearby Ambatovy mine site. Additional populations have been identified in two classified forests (Andriantantely and Tsinjoarivo), Marokitay Forest Reserve, and unprotected forests of Anosibe an’ala, Didy, lofa, Maromiza, and Sandranantitra. Tsinjoarivo Classified Forest has already been recommended as a new protected area, based on the presence of the unusual population of Diademed Sifakas found there.

Bibliography. Andriaholinirina et al. (2004), Andriamasimanana et al. (2001), Britt et al. (1999), Garbutt (2007), Glander et al. (1992), Green & Sussman (1990), Groves (2001), Irwin (2006, 2007, 2008a, 2008b), Irwin & Ravelomanantsoa (2004), Irwin et al. (2007), Lehman & Wright (2000), Lehman et al. (2005), Mayor et al. (2004), Mittermeier, Konstant, Hawkins et al. (2006), Mittermeier, Konstant, Nicoll & Langrand (1992), Mittermeier, Langrand et al. (2010), Nicoll & Langrand (1989), Petter (1962), Petter & Petter-Rousseaux (1979), Petter et al. (1977), Powzyk (1997), Powzyk & Mowry (2003), Rumpler et al. (2011), Simons (1988), Smith & Jungers (1997), Tattersall (1982, 1986b).

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. NE & E Madagascar from the Mananara River in the N to the Mangoro and Onive rivers in the S; although the precise distributional limits are unknown, the Diademed Sifaka is thought to be the most widely distributed of the sifakas, occurring throughout Madagascar’s E rainforests. Historically, its distribution extended farther N to just S of the Antainambalana River, but it has not been found in recent years during fairly extensive studies of that region.