Pygmy three-toed sloth

The dwarf sloth ( Bradypus pygmaeus ) is a species described in 2001 Faul from the family of three -toed sloths ( Bradypodidae ). The species is on the island of Escudo de Veraguas, which lies off the north coast of Panama in the province of Bocas del Toro, endemic. There she lives in the coastal mangrove forests, on the way of life is but little known. The existence of the dwarf sloth is considered threatened with extinction.

Features

Generally

The dwarf sloth is very similar to the brown -throated sloth ( Bradypus variegatus ), but is much smaller and therefore a typical case of Inselverzwergung. Reaching a total length of 48.5 to 53 cm, wherein the short tail thereby occupies from 4.5 to 6 cm, and a weight of 2.5 to 3.5 kg. With respect to the body weight is thus about 40 % smaller than the brown -throated sloth in relation to the body size about 15% smaller. The face is yellow- brown to brown and has a dark eyes ribbon to the skin appear slightly orange. The hair on the head and shoulders is long and shaggy, and forms a kind of hood to the short facial hair. The ears are small, more than 1 cm long, and not externally visible. The throat has a agoutifarbene to gray-brown tint. The back is mottled, but has a dark center strip. The coat is (hanging in the trees ), as in all sloths as an adaptation to their way of life parted from the belly away. Like all three-toed sloths also owns the dwarf sloth front and rear three-rayed feet, each with long claws. The hind foot reaches it from 9.4 to 11 cm in length.

Skull and dentition characteristics

The skull is delicately built, and from 6.7 to 7.2 cm long and at the zygomatic 3.8 to 4.6 cm behind the eyes but only a maximum of 2.2 cm wide. Typically, the zygomatic arch is not completely closed, but the front portion has a narrow, long extension that is directed downwardly. On the parietal parasagittal two weak backs are also trained. The rostrum is short and the front leg slightly swollen. In the upper jaw there are 5, 4 teeth in the lower jaw each half of the jaw, making a total of 18, the front are each smaller here and chisel- like shape, can partly be completely absent in the upper jaw, the posterior molars are similar. The upper row of teeth reached to almost 2.5 cm in length.

Dissemination

The species is endemic to the 4.3 km ² island of Escudo de Veraguas, which is about 17.6 km off the north coast of Panama in the province of Bocas del Toro. There the dwarf sloth is found exclusively in the Red Mangrove forests of the coastal zone. Outside the mangrove forests individual animals were observed only up to a maximum of 20 meters, in the forests of the interior of the island, the species is not yet proven. The entire inhabited area is given as 1.3 to 1.5 sq km, which corresponds to the spread of the Red Mangrove on Escudo de Veraguas, which actually covered by the mangrove area is 10.7 ha

Way of life

Little is known about the life of dwarf sloth. Like all three -toed sloths, it is likely to primarily feed on leaves and lead to compensate for the low nutritional value of its food energy-saving lifestyle. The type is both in the trees and on the ground go. The dwarf sloth is, as its large brother, a skilled swimmer. Reproductive behavior has not previously been investigated.

System

Vermilingua ( anteaters )

Choloepus (two -toed sloth )

Bradypus (three -toed sloths )

The dwarf sloth is a species in the genus of three -toed sloths ( Bradypus ), which belong to three other species. These in turn are part of today monotypic family of Bradypodidae, within the subordination of the sloth ( Folivora ) compared to all other groups sloth as a sister group. The next related still living group within the sloths is that of the two -toed sloth ( Choloepus ) from the family of Megalonychidae. The sloths in turn are more closely related to anteaters ( Vermilingua ) and together form the order of the tooth poor ( Pilosa ). The removal of the line of the sloth of the anteaters started by molecular genetic studies in the late Paleocene, about 58 million years ago. The two still living genera Bradypus and Choloepus parted, however, in the Lower Miocene epoch, about 22 million years ago.

Within the genus of three -toed sloths, the Brown -throated sloth is ( Bradypus variegatus ), the most closely related Art This is widespread in Central and South America and also occurs on some islands off the coast of Panama, so to Colón, Cayo Nancy and Bastimentos. The individuals of the different populations are somewhat similar in their coat patterns the dwarf sloth and are in their body size also significantly smaller than those of the populations on the mainland. The island of Escudo de Veraguas, however, lies much further from the mainland than the other islands. Due to rising sea water after the decay of the last ice age it was separated from the mainland about 8900 years ago. The Isla Colon, home of today's brown -throated sloth, arose in this way, however, until 5200 years ago - and at a much later date. The ancestors of the dwarf sloth were thus significantly longer separated from the other groups of the brown -throated sloth and so were subject to a stronger Inselverzwergung - estimated about 1500 generations until today - as the ancestors of the sloths is closer to the mainland islands. Despite the conspicuous smaller body proportions compared to Brown -throated sloths from the mainland, the sloth of the other islands off the coast of Panama are assigned to all of this kind. Thus, the distribution area of ​​Zergfaultiers is only limited to Escudo de Veraguas. Fossil finds of dwarf sloth are not available.

The dwarf was first described scientifically sloth 2001 by Robert P. Anderson and Charles Handley. The holotype ( specimen USNM Number 579 179 ) is an adult female with skin and skull that was collected by Handley and Penny Nelson on the island Escudo de Veraguas in March 1991. The holotype is preserved in the National Museum of Natural History in Washington, DC. The Latin species name paygmaeus here means as much as "dwarf".

Endangering

The dwarf sloth is due to its small distribution area - the home island is only about 4.3 square kilometers - in the IUCN Red List as " threatened with extinction " ( critically endangered ) listed and a new list even the hundred most endangered species counted. The size of the entire population is unknown, but is estimated to be less than 500 animals. During a three- week observation in 2011 a total of 79 animals were registered, mostly in mangrove trees, rarely in short distances would come to this. The island is home though uninhabited, but visiting fishermen, farmers and other people they temporarily and hunt the animals. Another danger is the development of the island for tourism, as expected, the presence of domestic cats have an impact on the stock. Currently, the dwarf sloth has received little attention from the public side. Originally unprotected Escudo de Veraguas is today a part of the nature reserve Comarca Indigenous Reserve dar.