Palorchestes
Encyclopedia
Palorchestes is an extinct genus
of terrestrial
herbivorous marsupial
of the family
Palorchestidae
. The genus was endemic to Australia
, living from the Late Miocene
subepoch through the Pleistocene
epoch (around 11.6 mya – 11,000 years ago), and thought to be in existence for approximately .
, being around 2.5 metres (8.2 ft) in length, and had four powerful legs. The appearance of the animal's nasal bones suggests that it possessed a short proboscis
, leading to the nickname of the "marsupial tapir". Since it is unrelated to tapir
s, this similarity in nose shape is an example of convergent evolution
. Palorchestes front legs bore large claw
s, similar to those of a koala
, which it probably used to pull down leaves and strip the bark from trees.
The long symphysis
at the lower jaw of all Palorchestes species indicates that the tongue was long and protrudible, like that of a giraffe.
.
, who first found what he thought was the fragmentary jaw of a prehistoric kangaroo. It was not until more postcranial elements were found did anyone realize that Palorchestes was actually a diprodontid, and not a kangaroo.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
herbivorous marsupial
Marsupial
Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Palorchestidae
Palorchestidae
The family Palorchestidae contains four genera with eight species described. All species are extinct.*Propalorchestes **P. novaculocephalus **P. painei *Ngapakaldia...
. The genus was endemic to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, living from the Late Miocene
Late Miocene
The Late Miocene is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch....
subepoch through the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
epoch (around 11.6 mya – 11,000 years ago), and thought to be in existence for approximately .
Description
One species, Palorchestes azael, was almost as large as a horseHorse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
, being around 2.5 metres (8.2 ft) in length, and had four powerful legs. The appearance of the animal's nasal bones suggests that it possessed a short proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
, leading to the nickname of the "marsupial tapir". Since it is unrelated to tapir
Tapir
A Tapir is a large browsing mammal, similar in shape to a pig, with a short, prehensile snout. Tapirs inhabit jungle and forest regions of South America, Central America, and Southeast Asia. There are four species of Tapirs: the Brazilian Tapir, the Malayan Tapir, Baird's Tapir and the Mountain...
s, this similarity in nose shape is an example of convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
. Palorchestes front legs bore large claw
Claw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...
s, similar to those of a koala
Koala
The koala is an arboreal herbivorous marsupial native to Australia, and the only extant representative of the family Phascolarctidae....
, which it probably used to pull down leaves and strip the bark from trees.
The long symphysis
Symphysis
A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint.1.A symphysis is an amphiarthrosis, a slightly movable joint.2.A growing together of parts or structures...
at the lower jaw of all Palorchestes species indicates that the tongue was long and protrudible, like that of a giraffe.
Discovery
Fossilized remains of Palorchestes azael have been found at the Naracoorte Caves fossil site in AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Etymology
The generic name was coined by Sir Richard OwenRichard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
, who first found what he thought was the fragmentary jaw of a prehistoric kangaroo. It was not until more postcranial elements were found did anyone realize that Palorchestes was actually a diprodontid, and not a kangaroo.
External links
- http://www.pacificislandbooks.com/kadil~1.jpg image
- Australia's Vanished Beasts - Palorchestid - Image and information