''Mekosuchus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

Australasian

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...

s within the subfamily

Mekosuchinae Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They first appear in the fossil record in the Eocene in Australia, and survived until the arrival of humans: in the Pleistocene in Australia and within the Holocene ...

. They are believed to have been made extinct by the arrival of humans on the South Pacific islands where they lived. The species of this genus were small in size, 2 m in maximum length, and

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

, making them the last surviving group of fully terrestrial crocodilians, leaving only semi-terrestrial species such as the

Cuban crocodile The Cuban crocodile (''Crocodylus rhombifer'') is a small-medium species of crocodile endemic to Cuba. Typical length is and typical weight . Large males can reach as much as in length and weigh more than . Despite its smaller size, it is a hig ...

and the dwarves ''

Osteolaemus ''Osteolaemus'' is a genus of crocodiles. They are small, secretive crocodiles that occur in wetlands of West and Middle Africa. They are commonly known as the African dwarf crocodiles. Unlike other crocodiles, ''Osteolaemus'' are strictly noct ...

'' and ''

Paleosuchus ''Paleosuchus'' is a South American genus of reptiles in the subfamily Caimaninae of the family Alligatoridae. They are the smallest members of the order Crocodilia in the Americas The Americas, which are sometimes collectively called ...

''. Fossils of related mekosuchines, such as ''

Trilophosuchus ''Trilophosuchus'' ("Triple Crest Crocodile") is an extinct genus of mekosuchine crocodilian from Australia. Unlike living crocodilians, it is hypothesized to have been terrestrial. ''Trilophosuchus'' was approximately in length. It had a shor ...

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

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

genus ''

Kambara ''Kambara'' is an extinct genus of mekosuchine crocodylian that lived during the Eocene epoch in Australia. Description At around 55 million years old, remains of ''Kambara'' are among the oldest Tertiary fossils found in Australia (although t ...

''), while ''

Quinkana ''Quinkana'' is an extinct genus of mekosuchine crocodylians that lived in Australia from about 28 million to about 10,000 years ago. Most attributed specimens have been found in Queensland. It is speculated to have been one of the top predator ...

'' survived until the arrival of humans.Roberts, R.G., Flannery, T.F., Ayliffe, L.K., Yoshida, H., Olley J.M., Prideaux, G.J., Laslett, G.M., Baynes, A., Smith, M.A., Jones, R., Smith, B.L. (2001). New Ages for the Last Australian Megafauna: Continent-Wide Extinction About 46,000 Years Ago. ''Science'' 292 (5523): 1888–1892
DOI: 10.1126/science.1060264
/ref> ''Mekosuchus'' survived until the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

, and their sub-fossils have been found in

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

and

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (french: link=no, République de Vanuatu; bi, Ripablik blong Vanuatu), is an island country located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of no ...

Species

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

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''M. inexpectatus'' from the Holocene of

which became extinct at some point in the last 4,000 years, most likely with the arrival of humans in the archipelago. ''Mekosuchus'' had specialized back teeth for cracking mollusk shells and arthropod carapaces, an adaptation in response to the lack of large ground-dwelling prey in

; although it was likely also an opportunistic hunter that went after lizards and various-sized birds when possible. Another

species is known, ''M. kalpokasi'' which lived on the island of

Éfaté Efate (french: Éfaté) is an island in the Pacific Ocean which is part of the Shefa Province in Vanuatu. It is also known as Île Vate. Geography It is the most populous (approx. 66,000) island in Vanuatu. Efate's land area of makes it Vanua ...

approximately 3,000 years ago and likewise disappeared with the arrival of humans. ''M. whitehunterensis'', the oldest known species, lived during the late

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

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

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

Phylogeny

A 2018

tip dating Tip dating is a technique used in molecular dating that allows the inference of time-calibrated phylogenetic trees. Its defining feature is that it uses the ages of the samples to provide time information for the analysis, in contrast with traditio ...

study by Lee & Yates simultaneously using morphological, molecular (

DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

), and

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

(

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

age) data established the inter-relationships within

Crocodylia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...

. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below shows the placement of ''Mekosuchus'' within

References

{{Taxonbar, from=Q604542, from2=Q371172, from3=Q1918871 Mekosuchinae Neogene crocodylomorphs Oligocene crocodylomorphs Miocene crocodylomorphs Terrestrial crocodylomorphs New Caledonia Holocene fauna Holocene extinctions Pliocene crocodylomorphs Pleistocene crocodylomorphs Taxa named by Jean-Christophe Balouet Prehistoric pseudosuchian genera

Species

Phylogeny

See also

References