The shrewlike rats, genus ''Rhynchomys'', also known as the tweezer-beaked rats are a group of unusual
Old World rats
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 excep ...
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 (
worm-eaters) and
insectivore
A robber fly eating a hoverfly
An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects.
The first vertebrate insectivores wer ...
s 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.
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
Needle may refer to:
Crafting
* Crochet needle, a tool for making loops in thread or yarn
* Knitting needle, a tool for knitting, not as sharp as a sewing needle
* Sewing needle, a long slender tool with a pointed tip
* Trussing needle, a long sl ...
-like and
mandibles as delicate.
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.
Distribution
Shrewlike rats are found at elevations of 1,100 to 2,460 meters.
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''),
Mount Banahao
Mount is often used as part of the name of specific mountains, e.g. Mount Everest.
Mount or Mounts may also refer to:
Places
* Mount, Cornwall, a village in Warleggan parish, England
* Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, ...
(''R. banahao''),
(''R. isarogensis''),
Mt. Labo of the
Bicol Peninsula (''R. labo'')
and
Mt. Mingan of the
Sierra Madre (''R. mingan'').
Relationships
''Rhynchomys'' is an
old endemic of the Philippines.
The genus is distinct enough to give it its own group distinct from all other old endemics.
It was classified as part of the ''Chrotomys'' division along with ''
Apomys
''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 Su ...
'', ''
Archboldomys'', and ''
Chrotomys
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 predo ...
''.
Within this division, ''Rhynchomys'' is most closely related to the other Philippine shrew-rats in the genera ''Archboldomys'' and ''Chrotomys''.
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.
In 2019, two additional species were described, ''R. labo'' and ''R. mingan'' from
Mt. Labo and
Mt. Mingan, respectively.
*
Banahao shrew-rat
The Banahao shrew-rat (''Rhynchomys banahao'') is a species 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 ...
(''Rhynchomys banahao'')
Balete ''et al.'', 2007
*
Isarog shrew-rat, (''Rhynchomys isarogensis'')
Musser and Freeman, 1981
*
Labo shrew-rat
The Labo shrew rat (''Rhynchomys labo'') 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.
References
...
(''Rhynchomys labo'')
Rickart ''et al.'', 2019
*
Mingan shrew-rat
The Mingan shrew rat (''Rhynchomys mingan'') 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.
R ...
(''Rhynchomys mingan'')
Rickart ''et al.'', 2019
*
Mount Data shrew-rat
The Mount Data shrew-rat (''Rhynchomys soricoides'') is a species of rodent in the family Muridae.
It is found only in the Philippines.
References
*
Rhynchomys
Mammals described in 1895
Taxa named by Oldfield Thomas
Taxonomy articles ...
(''Rhynchomys soricoides'')
Thomas, 1895
*
Tapulao shrew-rat (''Rhynchomys tapulao'')
Balete ''et al.'', 2007
References
{{Taxonbar, from=Q1189626
Rats of Asia
Rhynchomys
Endemic fauna of the Philippines
Fauna of Luzon
Rodents of the Philippines
Taxa named by Oldfield Thomas