THE DIADEMED SIFAKA LEMURS

 

 The diademed sifaka (Propithecus diadema), or diademed simpona, is an endangered species of sifaka, one of the lemurs endemic to certain rainforests in eastern Madagascar. Along with the indri, this species is one of the two largest living lemurs, with an average weight of 6.5 kg^[4] and a total adult length of approximately 105 centimetres (41 inches),^[5] half of which is its tail. Russell Mittermeier, one of the contemporary authorities on lemurs, describes the diademed sifaka as "one of the most colorful and attractive of all the lemurs", having a long and silky coat.^[6] P. diadema is also known by the Malagasy names simpona, simpony and ankomba joby. The term "diademed sifaka" is also used as a group species designation formerly encompassing four distinct subspecies.

   The diademed sifaka is a member of the genus Propithecus. It is the titular member of the P. diadema group, which includes the three species of eastern rainforest sifakas and the eastern dry forest Perrier's sifaka (P. perrieri),^[7] to the exclusion of the five members of the

 P. verreauxi group of western sifakas.^[16] The diademed sifaka's somatic number is 2n = 42.^[7] The X chromosome and 18 of its autosomal chromosomes are metacentric, 14 are submetacentric, and eight chromosomes and the Y chromosome are acrocentric.^[15][17] One of its metacentric chromosomes could have formed from a Robertsonian translocation between two acrocentric chromosomes, resulting in a reduced somatic number compared to the 2n = 44 seen in Milne-Edwards's sifaka (P. edwardsi).^[17] Like other lemurs, the diademed sifaka evolved on Madagascar.^[18]

 

 

conservation. Geographically the range extends to at least the Mananara River in the north to the Onive and Mongoro Rivers in the south. One set of researchers has recorded a clinal variation between Propithecus diadema and Propithecus edwardsi in the extreme southern portion of the range.^[8] As with all Indriidae, this species and its entire genus have evolved on the island of Madagascar independent of other mainland African species.^{[citation needed]}
An anomalous outlier population of P. diadema has been discovered in south central Madagascar; the members of this population exhibit an array of different colour markings, including at least one observation of an all black lemur. DNA analyses have not resulted in consistent results as to whether this group of individuals should constitute a new species. Scientists have decided to classify this outlier group as P. diadema until further research warrants designation of a separate species.^{[citation needed]}
Specific locations for sighting the diademed sifaka are Mantadia National Park (approximately three hours in driving time from the capital city of Antananarivo) and in the forests of Tsinjoarivo.^[9]

 

The diademed sifaka forms groups typically of two to ten individuals, which may include multiple male and female adults. Each troop defends an exclusive home territory of 25 to 50 hectares (62 to 125 acres) using perimeter scentterritorial marking by both the males and females. Although the diademed 

sifaka defends the group's territory strongly against other members of their same species, it will share territory with other species such as the red-bellied lemur and the common brown lemur. P. diadema is thought to traverse the greatest daily path 

 

distance relative to other members of its family in its patrolling and foraging, attaining a typical travel distance in excess of 1.6 kilometres (one mile) per day. To accomplish this it consumes a diet high in energy content and diverse in plant content, each day consuming over 25 different vegetative species. This diurnal lemur 

 

further diversifies its diet by consuming not only fruits, but certain flowers, seeds and verdant leaves, in proportions that vary by season.^{[citation needed]}

 

 For a large lemur, the diademed sifaka is rather athletic, being capable of lateral aerial propulsion of up to 30 kilometers per hour, a result of muscular leg thrusting action pushing off from a vertical tree trunk. It is possible, although not proven, that its vigorous health characteristics are enhanced from high consumption of two plants which contain high concentrations of alkaloids. This species is arboreal, and only rarely are seen on the ground; moreover, it is a vertical clinger and lateral leaper.
The diademed sifaka makes a warning call resembling the sound "kiss-sneeze" when a terrestrial predator 

 

is perceived;^[10] the sole terrestrial predators of P. diadema are the fossa and Nile crocodile.^{[citation needed]}
Sexual maturity occurs after age two or three, with the male maturing somewhat more slowly than the female. Little is known of mating behaviour; however, it is believed that the female is receptive to mating only a few days per year. Being dominant, the female has the greatest input to mate selection. Copulation occurs in the summer (around December), and the expected number of births is one offspring per female per annum.^{[citation needed]}

 

Conservation issues

 

The diademed sifaka is classified as critically endangered on the IUCN Red List, and is listed in CITES Appendix I.^[2] As of the year 2002, population estimates for the species range between 6,000 and 10,000 individuals.^[11] The primary threat is habitat reduction due to shifting cultivation by native peoples. This threat is also present even within designated national parks, which are sufficiently distant from the center of government, that enforcement of existing national laws protecting P. diadema habitat is problematic. Pressures of overpopulation in central and eastern Madagascar are causing many of the rural poor to seek subsistence by seizing whatever forest lands are available and undertaking slash-and-burn tactics as their initial step in a shifting cultivation system. Returns from such land use are usually meager, yielding small amounts of charcoal, firewood or grass crop for grazing of zebu.^{[citation needed]}

 

The diademed sifaka and three other sifaka species form a tight species group within the genus Propithecus. The other three species are Milne-Edwards' sifaka (Propithecus edwardsi), Perrier's sifaka (P. perrieri), and the silky sifaka (P. candidus). All of these species have luxuriant silky coats and are powerful 

 

leapers. They share similar characteristics of gestation length (four months), age of sexual maturity, female dominance, life expectancy (18 years) and propensity for sunbathing while stretched out on a branch. They differ distinctly in colouration and markings, except for having universally totally black faces.^{[citation needed]}