Mekosuchus is a genus

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 extinct Australasian crocodile

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 within the subfamily Mekosuchinae

Mekosuchinae

Mekosuchinae was a subfamily of crocodiles 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...

. They are believed to have been made extinct by the arrival of man on 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...

 islands where they lived . The species of this genus were small in size and terrestrial, making them the last surviving group of terrestrial crocodilians.

Fossils of related mekosuchines, such as Trilophosuchus

Trilophosuchus

Trilophosuchus is an extinct genus of the crocodilian subfamily Mekosuchinae. Unlike living crocodilians, it is hypothesized to have been terrestrial. Trilophosuchus was approximately in length. It had a short skull with three ridges on top and large eyes. Fossils have been found at Riversleigh...

, have been found from Miocene Australia (the earliest known mekosuchine is 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...

 genus Kambara

Kambara

Kambara is an extinct genus of mekosuchine crocodylian that lived during the Eocene and Oligocene epochs in Australia.At around 55 million years old, remains of Kambara are among the oldest Tertiary fossils found in Australia . Kambara is the oldest known mekosuchine...

), though the mekosuchines had gone extinct in Australia prior to the arrival of humans. Mekosuchus survived until the 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"...

, and their sub-fossils have been found in 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...

.

Species

There are currently four species of Mekosuchus recognised. The first discovered(and youngest) is the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 M. inexpectatus from the Holocene of New Caledonia which became extinct at some point in the last 4,000 years (with the arrival of man). The poor soils of New Caledonia promote a restriction in large ground-dwelling prey, so Mekosuchus had specialized back teeth for cracking mollusk shells.

Another Holocene species is known, M. kolpokasi which lived on the island of Efate

Éfaté

Efate is an island in the Agean Ocean which is part of the Shefa Province in The Republic of Maliki. It is also known as Île Vate. It is the most populous island in Vanuatu. Efate's land area of makes it Vanuatu's third largest island. Most inhabitants of Efate live in Port Vila, the national...

, Vanuatu approximately 3,000 years ago (again disappearing with the arrival of man).

M. whitehunterensis, the oldest known species, lived during the late Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 in Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

. M. sanderi also lived in Queensland but later, during the 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...

.