Shrewlike rat

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Shrewlike rat
Temporal range: Recent
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Celaenomys silaceus and Rhynchomys soricoides.jpg
Rhynchomys soricoides (lower animal)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Muridae
Tribe: Hydromyini
Genus: Rhynchomys
Thomas, 1895
Type species
R. soricoides
Species

Rhynchomys banahao
Rhynchomys isarogensis
Rhynchomys labo
Rhynchomys mingan
Rhynchomys soricoides
Rhynchomys tapulao

Contents

Distribution Rhynchomys.png
Distribution of shrewlike rats on Luzon Island. Orange = R. soricoides, red = R. tapulao, blue = R. banahao, and green = R. isarogensis.

The shrewlike rats, genus Rhynchomys, also known as the tweezer-beaked rats are a group of unusual Old World rats found only on the island of Luzon in the Philippines. They look a great deal like shrews and are an example of convergent evolution. Shrewlike rats evolved to be vermivores and insectivores feeding on soft-bodied invertebrates associated with leaf litter.

Characteristics

The snout and rostrum are very long. Eyes are small. Head and body is 18.8–21.5 cm with a tail 10.5–14.6 cm. [1] Only two molars are present on each side of the upper and lower jaws; these are small and peg-like. Incisors are described as needle-like and mandibles as delicate. [1] [2] Their characteristic method of locomotion has given rise to the epithet "hopping rats," describing their method of pouncing on an earthworm prey before it can slide back into its hole. [3]

Distribution

Shrewlike rats are found at elevations of 1,100 to 2,460 meters. [1] [2] They are restricted to moist, mossy highland regions with ample rainfall and large populations of earthworms. Populations appear to be very isolated, restricted to "sky islands" of Luzon. Specimens have been collected from Mt. Bali-it and Mt. Data of the Central Cordillera (R. soricoides), Mt. Tapulao of the Zambales Mountains (R. tapulao), [2] Mount Banahao (R. banahao), [2] Mount Isarog (R. isarogensis), Mt. Labo of the Bicol Peninsula (R. labo) [4] and Mt. Mingan of the Sierra Madre (R. mingan). [4]

Relationships

Rhynchomys is an old endemic of the Philippines. [5] The genus is distinct enough to give it its own group distinct from all other old endemics. [5] It was classified as part of the Chrotomys division along with Apomys , Archboldomys , and Chrotomys . [6] Within this division, Rhynchomys is most closely related to the other Philippine shrew-rats in the genera Archboldomys and Chrotomys. [7]

Species

From 1895 until 1981, Rhynchomys was only known from a few specimens taken from near the type locality of R. soricoides. In 1981, this was expanded by one species with the discovery and description of R. isarogensis. In 2007, two species, R. banahao and R. tapulao, were described from Mt. Banahao and Mt. Tapulao, respectively. [2] In 2019, two additional species were described, R. labo and R. mingan from Mt. Labo and Mt. Mingan, respectively. [8] [4]

Related Research Articles

<span class="mw-page-title-main">Murinae</span> Subfamily of rodents

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 except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the rodents.

<i>Chrotomys</i> Genus of rodents

The genus Chrotomys contain a unique group of rodents found only in the Philippines, specifically the islands of Luzon, Mindoro, and Sibuyan. Instead of being predominantly herbivorous or omnivorous like other murines, these rats feed predominantly on invertebrates although they do eat some vegetable matter. This vermivory is probably the result of a rat-like animal moving into an ecological niche usually filled by shrews. Shrews and other insectivores are absent on these Philippine islands.

<i>Apomys</i> Genus of rodents

Apomys, commonly known as earthworm mice, is a genus of rodent endemic to the Philippines. Mice belonging to this genus are generally called Philippine forest mice and can be found on most islands of the Philippines except in Palawan, the Sulu Archipelago, and the Batanes and Babuyan group of islands.

<i>Batomys</i> Genus of rodents

Batomys is a genus of rodent endemic to the Philippines. It has six extant described species.

<span class="mw-page-title-main">Cloud rat</span> Tribe of mammals

The cloud rats or cloudrunners are a tribe (Phloeomyini) of arboreal and nocturnal herbivorous rodents endemic to the cloud forests of the Philippines. They belong to the family Muridae and include five genera: Batomys, Carpomys, Crateromys, Musseromys, and Phloeomys. They range in size from as large as 50 cm (20 in) to as small as 74 mm (2.9 in). Cloud rats are threatened by habitat loss and illegal hunting. Several species are endangered or critically endangered.

<i>Archboldomys</i> Genus of rodents

Archboldomys, the shrew-mice, are a genus of rodents in the family Muridae. They are carnivores that feed on invertebrates much like shrews do. An apparently smaller relatives of the true shrew-rats Chrotomys and Rhynchomys, Archboldomys are somewhat convergent to the more distantly related Crunomys.

A shrew rat or shrew-rat is not a true rat but a rodent that resembles a shrew in physical form and, presumably, lifestyle. There are twelve known species distributed across seven known genera, all from island southeast Asia, specifically the Indonesian island of Sulawesi and several islands of the Philippines:

<span class="mw-page-title-main">Katanglad shrew-mouse</span> Species of rodent

The Katanglad shrew-mouse, also known as the Kitanglad shrew-mouse is a species of rodent in the family Muridae. It is known only from one specimen taken at 2250 m on Mount Kitanglad, Bukidnon Province, Philippines.

<span class="mw-page-title-main">Kalinga shrew mouse</span> Species of rodent

The Kalinga shrew mouse is a rodent of the genus Soricomys found in the northern province of Kalinga, island of Luzon, in the northern Philippines.

Musseromys is a genus of rodent, in the family Muridae, endemic to the Philippines. Four species are known, all from Luzon:

<span class="mw-page-title-main">Banahao shrew-rat</span> Species of rodent

The Banahao shrew-rat is a species of rodent in the genus Rhynchomys. It was described in 2007.

<span class="mw-page-title-main">Tapulao shrew-rat</span> Species of rodent

The Tapulao shrew-rat is a rodent in the subfamily Murinae. It was described in 2007.

<span class="mw-page-title-main">Sibuyan striped shrew-rat</span> Species of rodent

Sibuyan striped shrew-rat is a species of rodent in the family Muridae. The holotype was collected in 1992; however, it wasn't formally described until 2005.

Batomys uragon is a species of cloud rat endemic to the Philippines. It was first discovered in 1988, and the full description was published in 2015, in the Proceedings of the Biological Society of Washington. It is so far found only on Luzon, the largest island in the Philippines. The first specimen was collected from Mount Isarog at the southern side of the island. Other 14 specimens were later collected. It is the fourth species of mammal living only on that mountain. The new species was described by Danilo S. Balete, Eric A. Rickart, Lawrence R. Heaney, and Sharon A. Jansa. It was classified as new species based on DNA analyses and structural descriptions. It is different from its closest relative, the Luzon hairy-tailed rat, in its cytochrome b sequence, moderate body size, colour patterns, and skull structure.

<i>Soricomys</i> Genus of rodents

Soricomys, the shrew-mice, are a genus of rodents in the family Muridae. They are carnivores that feed on invertebrates much like shrews do. An apparently smaller relatives of the true shrew-rats Chrotomys and Rhynchomys, Soricomys are somewhat convergent to the more distantly related Crunomys.

The Labo shrew rat is a species of shrewlike rat in the subfamily Murinae. It was discovered at elevations above 1250 m on Mt. Labo of the Bicol Peninsula of Luzon in the Philippines and described in 2019.

The Mingan shrew rat is a species of shrewlike rat in the subfamily Murinae. It was discovered at elevations above 1450 m on Mt. Mingan of the central Sierra Madre of Luzon in the Philippines and described in 2019.

Danilo S. Balete, also known as Danny Balete, was a Filipino zoologist and biologist. His is known for his work on the Philippines' endemic mammal species. He pursued the question of what determines species diversity. The research by Balete and his team overturned previously held notions that diversity decreased in mountainous regions, showing that harsh environments could generate, rather than suppress, species diversity.

<span class="mw-page-title-main">Hydromyini</span> Tribe of rodents

Hydromyini is a very large, diverse tribe of muroid rodents in the subfamily Murinae. They are the dominant native rodents in Australasia and one of only two native rodent groups there, the other being the R. fuscipes group of the genus Rattus in the tribe Rattini. They are also found in parts of Southeast Asia.

The large Cordillera shrew-mouse is a species of rodent in the family Muridae found only in the Philippines.

References

  1. 1 2 3 Nowak, R. M.; Walker, E. P. (1999). Walker's Mammals of the World . JHU Press. ISBN   978-0801857898.
  2. 1 2 3 4 5 Balete, D. S.; Rickart, E. A.; Rosell-Ambal, R.G.B.; Jansa, S.; Heaney, L. R. (2007). "Descriptions of Two New Species of Rhynchomys Thomas (Rodentia: Muridae: Murinae) from Luzon Island, Philippines". Journal of Mammalogy. 88 (2): 287–301. doi:10.1644/06-MAMM-A-090R.1. JSTOR   4498659.
  3. "3 Questions with a Scientist: Hopping Rats". Field Museum of Natural History. June 6, 2019. Retrieved 4 December 2021.
  4. 1 2 3 Rickart, E. A; Balete, D. S; Timm, R. M; Alviola, P. A; Esselstyn, J. A; Heaney, L. R (2019). "Two new species of shrew-rats (Rhynchomys: Muridae: Rodentia) from Luzon Island, Philippines". Journal of Mammalogy. doi:10.1093/jmammal/gyz066. hdl: 1808/29417 .
  5. 1 2 Musser, G. G. & L. R. Heaney (2006). "Philippine rodents: Definitions of Tarsomys and Limnomys plus a preliminary assessment of phylogenetic patterns among native Philippine murines (Murinae, Muridae)". Bulletin of the American Museum of Natural History . 211: 1–138. hdl:2246/906.
  6. Musser, G.G.; Carleton, M.D. (2005). "Genus Rhynchomys". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 1497–1498. ISBN   978-0-8018-8221-0. OCLC   62265494.
  7. Jansa, S.; Barker, F. K.; Heaney, L. R. (2006). "The pattern and timing of diversification of Philippine endemic rodents: evidence from mitochondrial and nuclear gene sequences". Systematic Biology . 55 (1): 73–88. doi: 10.1080/10635150500431254 . PMID   16507525.
  8. Lanese, M. (6 June 2019). "Worms lure two new species of hopping rats out of obscurity". Science News . Retrieved 2016-06-09.