Myers' grass mice are typical of the genus Akodon. They are small, stout-bodied, short-limbed mice with relatively short tails. head and body length averages 93 mm and tail lengh 58 mm (40% of head and body length). The hind foot averages 17 mm long, without the claw, and ear length averages 12 mm. Average weight is 23 grams. The pelage is soft and somewhat long (10 mm dorsally). The dorsal pelage has agouti at the hair tips and is grayish on the hair bases. The venter is creamy, with grey on the distal 2 mm of the hairs, giving the venter a grayish appearance. The feet are covered with whitish fur and the tail is well-furred and distinctly scaled. The upper incisors are slightly opisodont and orange pigmented. (Nowak, 1991; Pardiñas, et al., 2005)
Akodon species by the following characters: condyloincisive length less than 24 mm, zygomatic breadth less than 13 mm, maxillary toothrow length less than 24 mm, a short rostrum - with the incisive foramen length measuring 5.6 mm on average, short and wide nasals, narrow zygomatic plate, wide mesopterygoid fossa with a median palatine process on the anterior border, an interorbital constriction between 4.3 and 4.6 mm wide, medium-sized auditory bullae, a diploid number of 2n=36, and a number of molecular synapomorphies from the mitochondrial cytochrome b gene. (Pardiñas, et al., 2005)is distinguished from other
Very little is known about reproduction in this newly described species. Reproductive condition was recorded for 12 individuals captured. Of these, 10 were reproductively active at the end of the summer season (March). Pregnant females had 3 or fewer embryos. Other Akodon species seem to have two litters per year of 3 to 4 young from August to May, although breeding seasons may vary. Akodon azarae, a related species, reproduce seasonally, giving birth to an average of 4.6 young per litter after a gestation period of 22.7 days. Delayed implantation may occur in A. azarae and sexual maturity occurred usually at 2 months. (Nowak, 1991)
There is no specific evidence regarding parental investment in this species. As mammals, females nurse and care for their young until they are weaned. Other Akodon species wean their young at 14 to 15 days old. (Nowak, 1991; Pardiñas, et al., 2005)
Nothing is known about lifespan in (Pardiñas, et al., 2005). It is likely that these rodents have relatively short lives, from 12 to 18 months in the wild.
Communication and perception have not been studied in this recently described species. Like most small, sigmodontine rodents, they are likely to rely extensively on hearing and olfaction in navigating the environment and in communicating with conspecifics. Their nocturnal habits also suggest that these modes of perception may be especially important.
Tyto alba) pellets and was found to represent a major proportion of barn owl prey in Northern Campos grasslands. They represented 30.7% of 182 prey items in one locality and 23% of 149 prey items in another locality. Other predators of are unknown. Although specific anti-predator adaptations are unknown in these grass mice, it is likely that they use their cryptic coloration, secretive, nocturnal habits, and vigilance to decrease their risk of predation. (Pardiñas, et al., 2005)was discovered during analysis of barn owl (
There are no known positive effects of (Pardiñas, et al., 2005)for humans, aside from their role as members of healthy, natural ecosystems.
There are no known negative impacts of (Pardiñas, et al., 2005).
Pinus and Eucalyptus), and cattle grazing. Several, large mammalian species have already been extirpated in this region (Blastocerus dichotomus, Myrmecophaga tridactyla, Panthera onca, Ozotoceros bezoarticus, and Pteronura brasiliensis). Northern Campos grasslands represent an area where northern and southern faunas mix, elevating biodiversity in this region. All individuals were captured in Northern Campos grassland areas, suggesting that they do not inhabit areas in the region converted to agriculture. With only 0.4% of Northern Campos grasslands protected, may be especially vulnerable to the effects of additional habitat destruction. (Pardiñas, et al., 2005)is a recently described species and its conservation status has not been extensively reviewed. It is the only known mammalian endemic species of the Northern Campos grasslands. This rare habitat has been extensively converted to agriculture, especially yerba mate, tea, introduced tree plantations (
Tanya Dewey (author), Animal Diversity Web.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
Nowak, R. 1991. Walker's Mammals of the World. Baltimore, Maryland: The Johns Hopkins University Press.
Pardiñas, U., G. D'Elía, S. Cirignoli, P. Suarez. 2005. A new species of Akodon (Rodentia, Cricetidae) from the Northern Campos grasslands of Argentina. Journal of Mammalogy, 86: 462-474.