The genus ''Chrotomys'' contain a unique group of
rodent
Rodents (from Latin , 'to gnaw') are mammals of the 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 rodents. They are n ...
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, as ...
,
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
Sibuyan is a crescent-shaped island, the second largest in an archipelago comprising Romblon Province, Philippines. Located in the namesake Sibuyan Sea, it has an area of and has a total population of 62,815 as of 2020 census. The island has ...
. 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 mouthpar ...
or
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 chorda ...
s although they do eat some vegetable matter. This vermivory is probably the result of a
rat-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 (for ...
usually filled by
shrews
Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different ...
. 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
Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are c ...
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
Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes.
F ...
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