The genus Chrotomys contain a unique group of rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s found only in the Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

, specifically the islands of Luzon

Luzon

Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...

, Mindoro

Mindoro

Mindoro is the seventh-largest island in the Philippines. It is located off the coast of Luzon, and northeast of Palawan. The southern coast of Mindoro forms the northeastern extremum of the Sulu Sea.-History:...

, and Sibuyan. Instead of being predominantly herbivorous

Herbivore

Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

 or omnivorous

Omnivore

Omnivores are species that eat both plants and animals as their primary food source...

 like other murines, these rats feed predominantly on invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

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

Rat

Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...

-like animal moving into an ecological niche

Ecological niche

In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...

 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

Genetics

Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 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
  Luzon Striped Rat
  The Luzon Striped Rat is a species of rodent in the family Muridae.It is found only in the Philippines.Its natural habitat is subtropical or tropical dry forests.-References:...
  
  , Chrotomys whiteheadi
• Mindoro Striped Rat
  Mindoro Striped Rat
  The Mindoro Striped Rat is a species of rodent in the family Muridae.It is found only in the Philippines.-References:* Baillie, J. 1996. . Downloaded on 19 July 2007....
  
  , Chrotomys mindorensis
• Isarog Striped Shrew-Rat
  Isarog Striped Shrew-Rat
  The Isarog Striped Shrew-rat or Mt Isarog Striped Rat is a species of rodent in the family Muridae.It is found only in the Philippines.Its natural habitat is subtropical or tropical dry forests.-References:...
  
  , Chrotomys gonzalesi
• Blazed Luzon Shrew Rat
  Blazed Luzon Shrew Rat
  The Blazed Luzon Shrew Rat is a species of rodent in the family Muridae.It is found only in Philippines.Its natural habitat is subtropical or tropical dry forests.-References:...
  
  , Chrotomys silaceus
• Sibuyan Striped Shrew Rat, Chrotomys sibuyanensis

Relationships as inferred by cytochrome b

Cytochrome b

Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...

Relationships as inferred by morphology

Morphology (biology)

In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....