The golden-crowned sifaka or Tattersall's sifaka (Propithecus tattersalli) is a medium-sized lemur characterized by mostly white fur, prominent furry ears, and a golden-orange crown. It is one of the smallest sifakas (genus Propithecus), weighing around and measuring approximately from head to tail. Like all sifakas, it is a vertical clinger and leaper, and its diet includes mostly seeds and leaves. The golden-crowned sifaka is named after its discoverer, Ian Tattersall, who first spotted the species in 1974. However, it was not formally described until 1988, after a research team led by Elwyn L. Simons observed and captured some specimens for captive breeding. The golden-crowned sifaka most closely resembles the western forest sifakas of the P. verreauxi group, yet its karyotype suggests a closer relationship with the P. diadema group of eastern forest sifakas. Despite the similarities with both groups, more recent studies of its karyotype support its classification as a distinct species.
Found in gallery, deciduous, and semi-evergreen forest, its restricted range includes 44 forest fragments, totaling an area of , centered on the town of Daraina in northeast Madagascar. Its estimated population is between 4,000 and 5,000 individuals. It is primarily active during the day, although it also tends to be active at dawn and dusk during the rainy season. It sleeps in tall emergent trees and is preyed upon by the fossa. The golden-crowned sifaka lives in groups of around five to six individuals, containing a balanced number of adult males and females. Scent is used to mark territories, which are defended by growling, chasing, and ritualistic leaping displays. Reproduction is seasonal, with gestation lasting six months and lactation lasting five months. Infants are weaned during the wet season to ensure the best chances of survival.
The small range and fragmented populations of this species weigh heavily on its survival. Forest fragmentation, habitat destruction, poaching, slash-and-burn agriculture, and other human factors threaten its existence. The golden-crowned sifaka is listed by the IUCN Red List as Critically Endangered. Its range was originally not covered by any national parks or protected areas in Madagascar, but a new protected area, Loky-Manambato reserve, was established in 2005 to include a portion. Attempts have been made to keep the golden-crowned sifaka in captivity at the Duke Lemur Center in Durham, North Carolina. The small colony was maintained from 1988 to 2008. In Madagascar, lawlessness resulting from the 2009 political coup led to increased poaching of this species, and many were sold to local restaurants as a delicacy.
Taxonomy and phylogeny The golden-crowned or Tattersall's sifaka (Propithecus tattersalli), known locally as ankomba malandy (or akomba malandy, meaning "white lemur"), was discovered in 1974 north of Vohemar in northeast Madagascar by Ian Tattersall, who observed but did not capture the animal. Unsure of its classification, Tattersall provisionally considered it a variant of the silky sifaka in his 1982 book, The Primates of Madagascar, citing its mostly off-white to yellowish fur, but also noting its uncharacteristic orange crown patch and tufted ears. Driven by a report in 1986 that the forest where Tattersall had observed this unique sifaka was contracted to be clear-cut for charcoal production, a research team from the Duke Lemur Center, led by Elwyn L. Simons, obtained permits to capture specimens for a captive breeding program. Simons and his team were the first to capture and observe the golden-crowned sifaka, formally describing it as a new species in 1988 and naming it in honor of Tattersall. The specimens were found northeast of Daraina, a village in the northeast corner of Madagascar.
There have been conflicting studies regarding the taxonomic status of the golden-crowned sifaka. When described by Simons in 1988, size, vocalizations, and karyotypes (the number and appearance of chromosomes) were compared with the other sifakas. In terms of size, general morphology, and vocalizations, the golden-crowned sifaka is more comparable to the western forest sifakas (known as the P. verreauxi group) in that it is smaller in length and weight. Its karyotype, however, is more similar to that of the eastern forest sifakas (known as the P. diadema group). The golden-crowned sifaka has 42 chromosomes (2n=42), 16 of which are autosomal pairs (not sex chromosomes) that are meta- or submetacentric (where chromosome arms are equal or unequal in length, respectively). The remaining autosomal pairs are smaller and acrocentric (with the shorter chromosome arm difficult to observe). Its X chromosome is metacentric, which is comparable to that of the P. diadema group, not the P. verreauxi group. Given the conflicting information, its geographic isolation, as well as the unique long fur tufts on the ears—a trait not shared by any other sifaka—the golden-crowned sifaka was recognized as a distinct species.
In 1997, comparisons of repeated DNA sequences within the family Indriidae supported Simon's classification, placing the golden-crowned sifaka as a sister group to the other sifakas. In 2001, a study involving mitochondrial DNA suggested a very recent divergence between it and the Coquerel's sifaka, then considered a subspecies of the P. verreauxi group. If this were true, the golden-crowned sifaka would not merit species status and would form a subclade with the Coquerel's sifaka within the P. verreauxi group. In 2004, a comparative study of the karyotypes of the three traditional species of sifakas provided insight into the chromosomal arrangements of all three groups. This study found that the golden-crowned sifaka differs from P. verreauxi group and P. diadema group by 9 and 17 chromosomal rearrangements respectively, and conversely argued that the golden-crowned sifaka is indeed a separate species and is more closely related to the P. verreauxi group. More recently, in 2007 a craniodental (skull and tooth) study provided evidence for 9 or 10 distinct sifaka species, including the golden-crowned sifaka. It also placed the golden-crowned sifaka within the P. verreauxi group.
Anatomy and physiology The golden-crowned sifaka is one of the smallest sifaka species with a weight of , a head-body length of , a tail length of , and total length of . It is comparable in size to the sifakas inhabiting the southern and western dry forests, such as Coquerel's sifaka, the crowned sifaka, Von der Decken's sifaka, and Verreaux's sifaka. It has a coat of moderately long, creamy-white fur with a golden tint, dark black or chocolate-brown fur on its neck and throat, pale orange fur on the tops of its legs and forelimbs, a white tail and hindlimbs, and a characteristic bright orange-gold crown. It is the only sifaka with prominent tufts of white fur protruding from its ears, making its head appear somewhat triangular and distinctive in appearance. Its eyes are orange, and its face is black and mostly hairless, with dark gray-black fur with white hairs stretching from beneath the eyes to the cheeks. Its snout is blunt and rounded, and its broad nose helps to distinguish it from other sifakas. Occasionally the bridge of the nose will have a patch of white fur. Similar to other sifakas, this arboreal animal has long, strong legs that enable it to cling and leap between tree trunks and branches.
Geographic range and habitat
The golden-crowned sifaka lives in dry deciduous, gallery, and semi-evergreen forests and is found at altitudes up to , though it seems to prefer lower elevations. Surveys have shown it to be limited to highly fragmented forests surrounding the town of Daraina in an area encircled by the Manambato and Loky Rivers in northeastern Madagascar. The golden-crowned sifaka has one of the smallest geographic ranges of all indriid lemur species. Out of 75 forest fragments studied by researchers, its presence could be definitively reported in only 44, totaling . This study, published in 2002, also estimated the total species population and observed population densities. Home range size varied between per group. With an average group size of five individuals, the population density ranged between 17 and 28 individuals per km2. Another home range size estimate of has also been suggested with a population density range of 10 and 23 individuals per km2. The forested area available to the species within its desired elevation range was estimated at , yielding an estimated population of 6,120–10,080 and a breeding population between 2,520 and 3,960 individuals. However, a study published in 2010 using line transect data from 2006 and 2008 in five major forest fragments yielded an estimated population of 18,000 individuals.
The species is sympatric (coexists) with two other medium-sized lemurs: the Sanford's brown lemur (Eulemur sanfordii) and the crowned lemur (Eulemur coronatus).
Behavior
The golden-crowned sifaka is primarily active during the day (diurnal), but researchers have witnessed activity in the early morning and evening (crepuscular) during the rainy season (November through April). In captivity, it has been observed feeding at night, unlike captive Verreaux's sifakas. It travels between per day, an intermediate range compared to other sifakas of the eastern forests. The golden-crowned sifaka can be observed feeding and resting higher in the canopy during the dry season (May through October). It sleeps in the taller trees (the emergent layer) of the forest at night.
When stressed, the golden-crowned sifaka emits grunting vocalizations as well as repeated "churrs" that escalate into a high-amplitude "whinney." Its ground predator alarm call, which sounds like "shē-fäk", closely resembles that of Verreaux's sifaka. It also emits mobbing alarm calls in response to birds of prey.
Diet
The diet of the golden-crowned sifaka consists of a wide variety of plants—as many as 80 species—whose availability varies based on the season. It is a seed predator, making seeds a year-round staple in its diet when available. The golden-crowned sifaka also eats unripe fruits, flowers, and leaves. One study showed a diet composition of 37% unripe fruit and seeds, 22% immature leaves, 17% mature leaves, 13% flowers, and 9% fruit pulp. Individuals have also been observed consuming tree bark during the dry season. In general, approximately 60% of its diet consists of unripe fruits and seed, mainly from leguminous pods, and less than 50% consists of leaves. At Daraina, it has been observed feeding on the sakoa tree (Poupartia caffra) and on mango trees. Immature leaves and flowers are eaten when available, in the early wet season. Daily traveling distance tends to increase when immature leaves are available. Studies have also shown that when food distribution is patchy, feeding times are shorter and more time is spent traveling. Dietary diversity has been shown to be consistent between populations, suggesting that it is important for the lemur to get a varied mix of nutrients and to protect itself from high levels of specific plant toxins.
A study in 1993 showed variability and flexibility in feeding preferences between three research sites around Daraina. Plant species preferences (measured in feeding time) changed between wetter, intermediate, and drier forests: