Maclear's rat (''Rattus macleari'') is an extinct large rat

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an Australian external territory comprising the island of the same name. It is located in the Indian Ocean, around south of Java and Sumatra and around north-west of the ...

in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

. It was one of two species of rat native to Christmas Island, alongside the

bulldog rat The bulldog rat (''Rattus nativitatis'') is an extinct species of rat formerly endemic to Christmas Island in the Indian Ocean. It was one of two rats endemic to Christmas Island, alongside Maclear's rat. Description The head and body length ...

. Abundant, unfamiliar with and seemingly unafraid of humans, large numbers of the creatures emerged and foraged in all directions at night. Making querulous squeaks, the rats entered the ''Challenger'' expedition's

tent A tent () is a shelter consisting of sheets of fabric or other material draped over, attached to a frame of poles or a supporting rope. While smaller tents may be free-standing or attached to the ground, large tents are usually anchored using gu ...

s and shelters in 1886, ran over sleepers, and upset everything in the search and fight for food. Maclear's rat might have been responsible for keeping the population of the

Christmas Island red crab The Christmas Island red crab (''Gecarcoidea natalis'') is a species of land crab that is endemic to Christmas Island and Cocos (Keeling) Islands in the Indian Ocean. Although restricted to a relatively small area, an estimated 43.7 million adu ...

in check, as recent numbers of the crab are greater than in the past. It is thought that

black rat The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is n ...

s inadvertently introduced by the expedition infected the Maclear's rats with a disease (possibly a trypanosome), which in turn could have contributed to the species' decline. The last recorded sighting was in 1903, although it is possible that Maclear's rats

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

ized with black rats. A hard tick ('' Ixodes nitens''), described as an

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

of Maclear's rat, is also thought to be extinct. MaclearsRatSkull

Said to be related to ''

Rattus xanthurus The yellow-tailed rat (''Rattus xanthurus'') is a species of rodent in the family Muridae. It is found only in northeastern Sulawesi, Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania ...

'' of Sulawesi and '' R. everetti'' of the Philippines, this species was grizzled brown above and lighter on the underside. The lower back had prominent long and black hairs that projected above the shorter fur. The base of the tail was dark with the distal half being scaly white. MaclearsRat-PLoSOne

The rat is named after Captain

John Maclear John Fiot Lee Pearse Maclear (27 June 1838 in Cape Town – 17 July 1907 in Niagara) was an admiral in the Royal Navy, known for his leadership in hydrography. He is best known for being commander of during the ''Challenger'' Expedition (1 ...

(1838–1907) of the British survey-ship HMS ''Flying-Fish'', who collected the specimen from Christmas Island in 1886. It was described as a new species by

Oldfield Thomas Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist. Career Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and subspecies for the first time. He was appoin ...

the next year, although it was originally described under the genus '' Mus''. Maclear was earlier commander on HMS ''Challenger'' for the ''Challenger'' Expedition of 1872–1876 under its commission captain, Sir

George Nares Vice-Admiral Sir George Strong Nares (24 April 1831 – 15 January 1915) was a Royal Navy officer and Arctic explorer. He commanded the ''Challenger'' Expedition, and the British Arctic Expedition. He was highly thought of as a leader an ...

. A DNA study found Maclear's rat to be the sister species of

Hainald's rat Hainald's rat (''Rattus hainaldi'') is a species of rodent in the family Muridae. It is found only on Flores Island in Indonesia, including on Mount Ranaka. Part of its habitat is protected within the Kelimutu National Park Kelimutu National ...

native to the island of

Flores Flores is one of the Lesser Sunda Islands, a group of islands in the eastern half of Indonesia. Including the Komodo Islands off its west coast (but excluding the Solor Archipelago to the east of Flores), the land area is 15,530.58 km2, and th ...

, with the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

containing the two being sister to the clade containing ''

Nesokia ''Nesokia'' is a genus of rodent in the family Muridae endemic to West Asia and Central Asia known as the short-tailed bandicoot rats. Species Genus ''Nesokia'' - short-tailed bandicoot rats: * Short-tailed bandicoot rat (''Nesokia indica'') G ...

'' and ''

Bandicota ''Bandicota'' is a genus of rodents from Asia known as the bandicoot rats. Their common name and genus name are derived from the Telugu language word ''pandikokku'' (పందికొక్కు). DNA studies have found the group to be a mon ...

''; this clade, in turn, is sister to the Australasian ''

Rattus ''Rattus'' is a genus of muroid rodents, all typically called rats. However, the term rat can also be applied to rodent species outside of this genus. Species and description The best-known ''Rattus'' species are the black rat (''R. rattus'') ...

'' radiation, making ''Rattus'' as currently defined

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

References

Rattus Extinct rodents Rodent extinctions since 1500 Extinct animals of Australia Fauna of Christmas Island Mammals described in 1887 Taxa named by Oldfield Thomas Mammal extinctions since 1500 {{Rattus-stub

See also

References