The genus ''Chrotomys'' contain a unique group of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...

s found only in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, specifically the islands of

Luzon Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, ...

Mindoro Mindoro is the seventh largest and eighth-most populous island in the Philippines. With a total land area of 10,571 km2 ( 4,082 sq.mi ) and has a population of 1,408,454 as of 2020 census. It is located off the southwestern coast of Luz ...

, and Sibuyan. Instead of being predominantly

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

like other

murine The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. Members of this subfamily are called murines. In terms of species richness, this subfamily is larger than all mammal families ex ...

s, these rats feed predominantly on

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s although they do eat some vegetable matter. This vermivory is probably the result of a

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

-like animal moving into an

ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (fo ...

usually filled by shrews. Shrews and other insectivores are absent on these Philippine islands.

Taxonomy

Rickart et al. (2005) found that ''C. mindorensis'', ''C. whiteheadi'', and ''C. gonzalesi'' are closely related whereas ''C. silaceus'' and ''C. sibuyanensis'' represent earlier offshoots of the genus. Several authors place ''C. silaceus'' in the genus ''Celaenomys'', but Rickart et al. (2005) suggest that neither genetic nor morphometric distance warrant it. These rats are considered "old endemics" and are probably the result of one of the first colonisations of the Philippine islands. Other murines colonised the islands at a later time and are more closely related to mainland murines.

Species

Genus ''Chrotomys'' - Luzon striped rats * Luzon striped rat, ''Chrotomys whiteheadi'' * Mindoro striped rat, ''Chrotomys mindorensis'' * Isarog striped shrew-rat, ''Chrotomys gonzalesi'' * Blazed Luzon shrew-rat, ''Chrotomys silaceus'' * Sibuyan striped shrew-rat, ''Chrotomys sibuyanensis''

Relationships as inferred by cytochrome b

Relationships as inferred by morphology

References

*Nowak, R.M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London. *Rickart, E. A., L. R. Heaney, S. M. Goodman, and S. Jansa. 2005. Review of the Philippine genera ''Chrotomys'' and ''Celaenomys'' (Murinae) and description of a new species. Journal of Mammalogy, 86:415-428. {{Taxonbar, from=Q867078 Rodents of the Philippines Endemic fauna of the Philippines Fauna of Luzon Fauna of Mindoro Fauna of Romblon Rodent genera Taxa named by Oldfield Thomas