Nesomyines probably sense their environment through vision, hearing, touch, smell, and taste, as do most mammals. Many have large eyes and ears and long vibrissae, suggesting keen visual, auditory, and tactile abilities. Some nesomyine species live in small family groups and give alarm calls to warn their offspring when predators approach.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
This subfamily consists of endemic species with restricted ranges that are highly vulnerable to habitat loss. As a result, 8 of the 23 species in this group are on the IUCN's Red List of Threatened Species. Two of these species are critically endangered (Eliurus penicillatus and Macrotarsomys ingens), two are endangered (Eliurus majori and Hypogeomys antimena), one is vulnerable (Gymnuromys roberti), and three are lower risk (Brachyuromys betsileoensis, Brachyuromys ramirohitra, and Eliurus webbi). One species, the endangered Malagasy giant rat (Hypogeomys antimena), is being bred and studied in captivity at the Jersey Zoo by the Durrell Wildlife Conservation Trust.
The subfamily Nesomyinae is a diverse group of muroid rodents endemic to Madagascar. There are 23 nesomyine species in nine genera.
There are no known negative effects of nesomyines on humans.
There are no known positive effects of nesomyines on humans.
Nesomyines are primary consumers that provide food for upper level consumers such as carnivorous mammals and snakes. They are parasitized by nematodes and ticks.
Commensal/Parasitic Species:
These rodents are herbivores that feed on fruit, seeds, berries, roots, and stems. They are not known to cache their food.
Primary Diet: herbivore (Frugivore , Granivore )
Nesomyine rodents are only found on Madagascar.
Biogeographic Regions: ethiopian (Native )
Other Geographic Terms: island endemic
Nesomyines live in a wide variety of habitats, including grasslands, wet meadows, sandy coastal forests, dry scrublands, and wet or dry inland forests. They range from sea level to 2,400 meters in elevation.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest
Aquatic Biomes: coastal
The lifespan of nesomyines has not been reported.
Nesomyines are characterized by their morphological and ecological diversity. Typically they are medium to large gerbil-like, vole-like, or rat-like rodents. They measure 80 to 350 mm in head and body length and their tails range from 60 to 250 mm. Nesomyines weigh 21 to 1,500 grams. In some species, females weigh less than males, in other species, there is no sexual dimorphism. Nesomyine tails are short to long, naked to moderately furred, and sometimes tufted. Some have prehensile tails. The hind feet range from wide and short to narrow and long, and most have no hair on the soles. The pelage is long and soft or thick and woolly. It is sandy brown, reddish, or gray on the dorsum and yellowish white, white, or gray on the venter. Most nesomyines have large eyes and prominent ears and whiskers.
The nesomyine dental formula is 1/1, 0/0, 0/0, 3/3 = 16. The incisors are opisthodont. The molars are rooted, have a biserial cusp arrangement, and range from brachydont to hypsodont. In most species, the third molar is equal in size to the first two molars. Nesomyines have strong zygomatic arches with large jugals. Most species have ventrally constricted infraorbital foramina. There is a prominent interparietal bone. The bony palate is wide and smooth and bears one pair of posterior palatine foramina. The pterygoid fossae are flat and level with the bony palate. Most species have a large postglenoid foramen, and all species have an accessory tympanum and malleus of parallel construction. Nesomyines have 13 thoracic and 7 lumbar vertebrae. There are three circumvallate papillae on the tongue, and the stomach consists of a single chamber. The soft palate bears three premolar and five intermolar ridges.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; male larger
Nesomyines are preyed upon by snakes, raptors, and mammalian carnivores. Some species give alarm calls and quickly retreat into underground burrows when danger threatens.
Known Predators:
The mating system has not been studied for all nesomyine species, but at least one species, the Malagasy giant rat (Hypogeomys antimena), is known to be monogamous and mate for life.
Mating System: monogamous
The reproductive behavior of some nesomyine species is entirely unknown. Therefore, the following may or may not apply to the entire group. Nesomyines reproduce during the wet season, and some species have just a single litter per year. Gestation lasts up to 138 days and there are one to four young per litter. Sexual maturity is not reached until the age of two years in some species.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Female nesomyines nurse their offspring for up to six weeks in a sheltered spot such as a tree cavity or underground nest chamber. In monogamous species, males may risk predation themselves by keeping watch for danger and protecting their offspring. Also, in those species that live in family groups, such as Hypogeomys antimena, young females remain with their parents for more than a year, not dispersing until after their parents have a new litter.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male); pre-independence (Protecting: Male); post-independence association with parents
The Malagasy rodents are the sole members of the subfamily Nesomyinae.[1] These animals are the only native rodents of Madagascar, come in many shapes and sizes, and occupy a wide variety of ecological niches. There are nesomyines that resemble gerbils, rats, mice, voles, and even rabbits. There are arboreal, terrestrial, and semi-fossorial varieties.
These rodents are clearly most closely related to some muroid rodents found on the African mainland. Some molecular phylogeneticists consider this clade of Malagasy and African rodents to represent a distinct family, the Nesomyidae. Other researchers place the Nesomyinae into a large family, Muridae, along with all members of the superfamily Muroidea.
It has been reported that the Nesomyinae is not monophyletic,[2] but this has not been supported in other analyses. Additionally, there were problems with this particular study, notably the use of Calomyscus as an outgroup while more distantly related muroids (rhyzomyines) were included in the ingroup. It seems likely that all rodents in Madagascar are descendants from a single invasion of the island.
If monophyletic, the nesomyines represent one of only four colonization events of terrestrial mammals from mainland Africa. The other groups are tenrecs, lemurs and Malagasy carnivorans. Molecular clock analyses suggest that the ancestor of the nesomyines colonized Madagascar about 20-25 million years ago.[3] This is at approximately the same time as the Malagasy carnivorans, but is considerably more recent than the estimated colonization times of tenrecs and lemurs.
Nesomyinae contains 9 genera and 27 species.
Subfamily Nesomyinae - Malagasy rodents
The Malagasy rodents are the sole members of the subfamily Nesomyinae. These animals are the only native rodents of Madagascar, come in many shapes and sizes, and occupy a wide variety of ecological niches. There are nesomyines that resemble gerbils, rats, mice, voles, and even rabbits. There are arboreal, terrestrial, and semi-fossorial varieties.
These rodents are clearly most closely related to some muroid rodents found on the African mainland. Some molecular phylogeneticists consider this clade of Malagasy and African rodents to represent a distinct family, the Nesomyidae. Other researchers place the Nesomyinae into a large family, Muridae, along with all members of the superfamily Muroidea.
It has been reported that the Nesomyinae is not monophyletic, but this has not been supported in other analyses. Additionally, there were problems with this particular study, notably the use of Calomyscus as an outgroup while more distantly related muroids (rhyzomyines) were included in the ingroup. It seems likely that all rodents in Madagascar are descendants from a single invasion of the island.
If monophyletic, the nesomyines represent one of only four colonization events of terrestrial mammals from mainland Africa. The other groups are tenrecs, lemurs and Malagasy carnivorans. Molecular clock analyses suggest that the ancestor of the nesomyines colonized Madagascar about 20-25 million years ago. This is at approximately the same time as the Malagasy carnivorans, but is considerably more recent than the estimated colonization times of tenrecs and lemurs.
