Mekosuchinae
Encyclopedia
Mekosuchinae was a subfamily of crocodile
s from Australia
and the South Pacific
that have now become extinct. They first appear in the fossil record in the Eocene
in Australia, and survived until the Pleistocene
in Australia and until the arrival of humans in the Pacific islands of Fiji
, New Caledonia
and Vanuatu
. There is however disagreement on whether or not Mekosuchinae is a subfamily within Crocodylidae, or a distinct family, Mekosuchidae, on its own within the superfamily Crocodyloidea.
Mekosuchine crocodiles were a diverse group. One of the last species, from Holocene
New Caledonia, called Mekosuchus inexpectatus
may have been arboreal. The early Miocene
species, Harpacochampsa
camfieldensis, may have resembled a false gharial
. Another mekosuchine fossil, currently undescribed, has been found in Miocene deposits from New Zealand
. One genus, Mekosuchus, managed to spread to the islands of the Pacific; it is believed to have island-hopped across the Coral Sea
, moving first to a now submerged island known as Greater Chesterfield Island, then New Caledonia and onwards.
In the Pleistocene
, the Quinkana
was one of the top terrestrial predators
of the Australian continent.
Mekosuchines became extinct in Australia after the arrival of crocodiles from the genus Crocodylus
, today represented by the Saltwater Crocodile
. The group survived on Vanuatu and New Caledonia until the arrival of people, who are presumed to have driven them to extinction.
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
s from 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...
and the South Pacific
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
that have now become extinct. They first appear in the fossil record in the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
in Australia, and survived until 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 ....
in Australia and until the arrival of humans in the Pacific islands of Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
, New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
and Vanuatu
Vanuatu
Vanuatu , officially the Republic of Vanuatu , is an island nation located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is some east of northern Australia, northeast of New Caledonia, west of Fiji, and southeast of the Solomon Islands, near New Guinea.Vanuatu was...
. There is however disagreement on whether or not Mekosuchinae is a subfamily within Crocodylidae, or a distinct family, Mekosuchidae, on its own within the superfamily Crocodyloidea.
Mekosuchine crocodiles were a diverse group. One of the last species, from Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
New Caledonia, called Mekosuchus inexpectatus
Mekosuchus
Mekosuchus is a genus of extinct Australasian crocodiles within the subfamily Mekosuchinae. They are believed to have been made extinct by the arrival of man on the South Pacific islands where they lived...
may have been arboreal. The early Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
species, Harpacochampsa
Harpacochampsa
Harpacochampsa camfieldensis is a poorly known Early Miocene crocodilian from the Bullock Creek lagerstatte of the Northern Territory. The current specimen consists of a partial skull and fragments of a slender snout reminiscent of that of a false gharial. It is tentatively placed within...
camfieldensis, may have resembled a false gharial
False gharial
The false gharial , also known as the Malayan gharial, false gavial, or Tomistoma is a freshwater crocodile of the Crocodylidae family with a very thin and elongated snout...
. Another mekosuchine fossil, currently undescribed, has been found in Miocene deposits from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. One genus, Mekosuchus, managed to spread to the islands of the Pacific; it is believed to have island-hopped across the Coral Sea
Coral Sea
The Coral Sea is a marginal sea off the northeast coast of Australia. It is bounded in the west by the east coast of Queensland, thereby including the Great Barrier Reef, in the east by Vanuatu and by New Caledonia, and in the north approximately by the southern extremity of the Solomon Islands...
, moving first to a now submerged island known as Greater Chesterfield Island, then New Caledonia and onwards.
In 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 ....
, the Quinkana
Quinkana
Quinkana is an extinct genus of mekosuchine crocodile that lived in Australia from ~24 million years ago to ~40,000 years ago. By the Pleistocene Quinkana had become one of the top terrestrial predators of Australia, possessing long legs and ziphodont teeth .Ziphodont teeth tend to arise in...
was one of the top terrestrial predators
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
of the Australian continent.
Mekosuchines became extinct in Australia after the arrival of crocodiles from the genus Crocodylus
Crocodylus
Crocodylus is one of three genera from the Crocodylinae subfamily extending from the Crocodylidae family.Established species include three extinct species:* † Crocodylus acer - probably represents a distinct genus....
, today represented by the Saltwater Crocodile
Saltwater Crocodile
The saltwater crocodile, also known as estuarine or Indo-Pacific crocodile, is the largest of all living reptiles...
. The group survived on Vanuatu and New Caledonia until the arrival of people, who are presumed to have driven them to extinction.