Rattus nativitatis

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Synapsida
Cladus: Eupelycosauria
Cladus: Sphenacodontia
Cladus: Sphenacodontoidea
Cladus: Therapsida
Cladus: Theriodontia
Cladus: Cynodontia
Cladus: Eucynodontia
Cladus: Probainognathia
Cladus: Prozostrodontia
Cladus: Mammaliaformes
Classis: Mammalia
Subclassis: Trechnotheria
Infraclassis: Zatheria
Supercohors: Theria
Cohors: Eutheria
Infraclassis: Placentalia
Cladus: Boreoeutheria
Superordo: Euarchontoglires
Ordo: Rodentia
Subordo: Myomorpha
Superfamilia: Muroidea

Familia: Muridae
Subfamilia: Murinae
Genus: Rattus
Species: R. nativitatis
Vernacular names
References

Rattus nativitatis in Mammal Species of the World.
Wilson, Don E. & Reeder, DeeAnn M. (Editors) 2005. Mammal Species of the World – A Taxonomic and Geographic Reference. Third edition. ISBN 0-8018-8221-4.

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 was about 25 to 27 centimetres (9.8 to 10.6 in), considerably larger than black rats, and their backs were covered in a two-centimetre thick layer of fat. They have been estimated to weigh 250 to 300 grams (8.8 to 10.6 oz). They had short, thick tails estimated to be around 17.5 centimetres (6.9 in) long. Their hair was described as being thick, coarse and dark reddish-brown in colour, with a slightly lighter underside.[2] Despite being traditionally thought to be a part of the genus Rattus, the bulldog rat is now thought to be nested within Bunomys, a genus otherwise endemic to Sulawesi and the surrounding islands.[3]
Life history

The rats lived on the higher hills and denser forests of the island. They lived in small colonies, in burrows among the roots of trees or under hollow logs of sago palms in primary forest. They were sluggish and never climbed. Bulldog rats have been suggested to have been half-dazed in daylight and were strictly nocturnal.[2]
Extinction

The last record dates from 1903. They are suggested to have succumbed to a disease brought by black rats that had been inadvertently introduced by sailors, as mass die-offs are noted around 1902–1903, after which they were never seen again.[4]
Skulls of R. nativitatis and R. macleari
References

Lamoreux, J.; Burbidge, A.A.; Woinarski, J. (2016). "Rattus nativitatis". IUCN Red List of Threatened Species. 2016: e.T19351A22443478. doi:10.2305/IUCN.UK.2016-1.RLTS.T19351A22443478.en. Retrieved 11 November 2021.
"Rattus nativitatis — Bulldog Rat, Christmas Island Burrowing Rat". Species Profile and Threats Database www.environment.gov.au. Archived from the original on 2 June 2011. Retrieved 11 June 2020.
Ali, Jason R; Aitchison, Jonathan C; Meiri, Shai (5 May 2020). "Redrawing Wallace's Line based on the fauna of Christmas Island, eastern Indian Ocean". Biological Journal of the Linnean Society. 130 (1): 225–237. doi:10.1093/biolinnean/blaa018. ISSN 0024-4066.

Wyatt KB, Campos PF, Gilbert MT, Kolokotronis SO, Hynes WH, et al. (2008). "Historical mammal extinction on Christmas Island (Indian Ocean) correlates with introduced infectious disease". PLOS ONE. 3 (11): e3602. Bibcode:2008PLoSO...3.3602W. doi:10.1371/journal.pone.0003602. PMC 2572834. PMID 18985148.

Further reading
Flannery, Tim & Schouten, Peter (2001). A Gap in Nature: Discovering the World's Extinct Animals. Atlantic Monthly Press, New York. ISBN 978-0-87113-797-5.