One set of researchers has recorded a clinal variation between Propithecus diadema and Propithecus edwardsi in the extreme southern portion of the range. As with all Indriidae, this species and its entire genus have evolved on the island of Madagascar independent of other mainland African species. 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. 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. Behaviour 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 scent territorial 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. 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.