Archaeoindris
Encyclopedia
Archaeoindris fontoynonti is an extinct species
of Malagasy
lemur
that was the largest primate
to evolve on Madagascar
. It weighed about 200 kg (440.9 lb) and measured around 1.5m in height, more than a silverback gorilla
. Archaeoindris is one of eight known members of the Palaeopropithecinae
subfamily. Archaeoindris belongs to a lineage of lemurs called "sloth lemurs" because they are built similarly to modern South America
n tree sloth
s. Initially, its large body size, and the anatomy of its femur
, suggested a similar mode of life to ground sloths, and Archaeoindris was believed to be almost exclusively terrestrial. As more fossil material came to light, however, it turned out that its arms and legs were better adapted for slow, ponderous climbing. Phalangeal curvature in primates is correlated with hand and foot function; highly suspensory forms such as the orangutan
possess the most curved phalanges. Sloth lemurs, of which Archaeoindris is one, are characterized by very curved proximal phalanges, approaching that of orangutans. However, the data presented in the reference does not include measurements from Archaeoindris, possibly because phalanges had not been recovered at that time.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of Malagasy
Malagasy fauna
The fauna of Madagascar is a part of the wildlife of Madagascar.Madagascar has been an isolated island for about 70 HI million years, breaking away from Africa around 165 million years ago, then from India nearly 100 million years later...
lemur
Lemur
Lemurs are a clade of strepsirrhine primates endemic to the island of Madagascar. They are named after the lemures of Roman mythology due to the ghostly vocalizations, reflective eyes, and the nocturnal habits of some species...
that was the largest primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
to evolve on Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. It weighed about 200 kg (440.9 lb) and measured around 1.5m in height, more than a silverback gorilla
Gorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...
. Archaeoindris is one of eight known members of the Palaeopropithecinae
Palaeopropithecinae
The sloth lemurs is an extinct clade of lemurs that includes four genera. Despite their common names, members of Palaeopropithecidae were not closely related to sloths but were closely related to the other lemur species....
subfamily. Archaeoindris belongs to a lineage of lemurs called "sloth lemurs" because they are built similarly to modern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n tree sloth
Sloth
Sloths are the six species of medium-sized mammals belonging to the families Megalonychidae and Bradypodidae , part of the order Pilosa and therefore related to armadillos and anteaters, which sport a similar set of specialized claws.They are arboreal residents of the jungles of Central and South...
s. Initially, its large body size, and the anatomy of its femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, suggested a similar mode of life to ground sloths, and Archaeoindris was believed to be almost exclusively terrestrial. As more fossil material came to light, however, it turned out that its arms and legs were better adapted for slow, ponderous climbing. Phalangeal curvature in primates is correlated with hand and foot function; highly suspensory forms such as the orangutan
Orangutan
Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...
possess the most curved phalanges. Sloth lemurs, of which Archaeoindris is one, are characterized by very curved proximal phalanges, approaching that of orangutans. However, the data presented in the reference does not include measurements from Archaeoindris, possibly because phalanges had not been recovered at that time.