text: monticolomys monticolomys is a genus of rodents within the subfamily nesomyinae of the family nesomyidae , and is closely related to macrotarsomys . the only species , monticolomys koopmani , also known as the malagasy mountain mouse or koopman 's montane voalavo , is found in the highlands of eastern madagascar . a small mouse - like rodent , m. koopmani is dark brown on the upperparts and dark gray below . it has small , rounded , densely haired ears and broad feet with well - developed pads . the long tail lacks a tuft at the tip . the skull is delicate and lacks crests and ridges on its roof . first collected in 1929 , monticolomys koopmani was not formally described until 1996 , but it is now known to have a broad distribution . active during the night , it occurs in both montane forest and human - disturbed grasslands and feeds on fruits and seeds . a scansorial animal , it climbs trees but also lives on the ground . although habitat destruction may pose a threat , it is classified as " least concern " on the iucn red list . taxonomy a specimen of monticolomys koopmani was captured in 1929 during the mission zoologique franco - anglo - américaine to madagascar , but the rodents obtained by the expedition were never studied in detail . it was not until the 1970s that karl koopman and guy musser recognized that the animal — whose skin had landed at the american museum of natural history in new york , while the skull was at the muséum national d 'histoire naturelle in paris — represented an otherwise unknown species . however , they never published their results . in 1993 , steven goodman rediscovered the species on madagascar and in 1996 he and michael carleton finally published a formal description . they named the animal monticolomys koopmani , as the sole member of a new genus . the generic name monticolomys means " mountain - dwelling mouse " and refers to the animal 's montane habitat , and the specific name koopmani honors karl koopman for his many contributions to mammalian systematics . common names in use for the animal include " koopman 's montane voalavo " and " malagasy mountain mouse " . the indigenous rodents of madagascar , the nesomyinae , prior to the discovery of monticolomys comprised seven very distinctive genera — so distinct from each other that some have found it difficult to accept that they are closely related . monticolomys , however , does not follow this pattern , in that it is similar and closely related to the gerbil - like genus macrotarsomys of western madagascar . this relationship was originally proposed by goodman and carleton based on morphology , and was strongly supported by a dna sequence analysis ( based on the cytochrome b gene ) published in 1999 . while this study provided some weak support for a relationship between the macrotarsomys – monticolomys clade and the giant jumping rat , hypogeomys , a later study based on the irbp gene instead placed macrotarsomys – monticolomys sister to a clade containing four other nesomyine genera — eliurus , voalavo , gymnuromys , and brachytarsomys . description monticolomys koopmani is a small , mouse - like rodent , and quite different in appearance from most other nesomyines . it has a thick , soft fur , which appears dark brown on the upperparts . the cover hairs ( which comprise most of the fur ) are tricolored : for the basal two thirds of their length , they are plumbeous gray ; the middle is ochraceous ; and the tip is dark brown to black . the longer guard hairs , which are most common towards the middle of the back , are completely black . the fur of the underparts appears dark gray , and is not sharply demarcated from the upperparts . there , the hairs are also plumbeous at the bases , but the tips range from white to yellowish - brown . the mystacial vibrissae — whiskers above the mouth — are medium - sized . the short , rounded ears are densely covered with grayish hairs . monticolomys has broad hindfeet bearing prominent pads and long outer digits . there are white hairs on the upper sides of the metapodials and digits , and long ungual tufts — tufts of hair surrounding the bases of the claws — are present . the thumb of the forefeet bears a nail , but claws are present on the other digits . the long tail is covered with small scales and light brown hairs . the tail lacks a distinct tuft at the tip , as is present in eliurus and macrotarsomys . females have six mammae . head and body length is 84 to 101 mm ( 3 . 3 to 4 . 0 in ) , tail length is 116 to 143 mm ( 4 . 6 to 5 . 6 in ) , hindfoot length is 23 to 25 mm ( 0 . 91 to 0 . 98 in ) , ear length is 15 to 20 mm ( 0 . 59 to 0 . 79 in ) , and body mass is 18 . 5 to 27 . 5 g ( 0 . 65 to 0 . 97 oz ) . the skull is small and delicate . the front part , the rostrum , is narrow and relatively long . the nasal bones are rounded at the front , but blunt at the back . the zygomatic plate — a bony plate at the side of the skull — is narrow and extends back to the front margin of the first upper molar ( m1 ) . the jugal bones constitute much of the thin zygomatic arches ( cheekbones ) . the interorbital region , between the eyes , is narrow and hourglass - shaped . there are no crests or ridges on the interorbital region or on the braincase . the incisive foramina , openings in the front part of the palate , extend back to a point between the front roots of the m1s . the bony palate itself is broad and lacks many indentations and protuberances present in other species . its posterior margin is at the level of the upper third molars ( m3s ) . there is no alisphenoid strut , so that the masticatory - buccinator foramen and the foramen ovale accessorium , two openings on the underside of the skull , are fused . there are 13 thoracic ( chest ) , 7 lumbar ( abdomen ) , 4 sacral ( hip ) , and 38 caudal ( tail ) vertebrae . the upper incisors have orange enamel and are opisthodont , with the cutting edge of the tooth inclined backwards . the root of the lower incisors extends though the mandible ( lower jaw ) to a low capsular process at the back of the jawbone . the molars are brachyodont ( low - crowned ) and bear distinct cusps . the second molars , although decidedly smaller than the first , are similar in their crown morphology , but the much smaller third molars are reduced and more distinct from the first molars in morphology . the molars lack accessory crests and other features . each of the upper molars is three - rooted , whereas the lowers have two roots . the molars are quite similar to those of macrotarsomys , and differ only in minor details . distribution and ecology the range of monticolomys is now known to extend across the mountain ranges of eastern madagascar from the tsaratanana massif south to andohahela , at 800 to 2 , 200 m ( 2 , 600 to 7 , 200 ft ) above sea level . it occurs in montane forest , but also in degraded grassland , where it is among the first species to return after fires . at ankaratra , where the species was recorded in 1929 , it occurred in such grassland , where the nesomyine brachyuromys was also found . the animal was again recorded at ankaratra in 1996 , this time in a heavily disturbed forest , where it occurred with eliurus minor and the introduced black rat ( rattus rattus ) . at andringitra , the animal was recorded in high montane forest together with six other nesomyines — brachyuromys , eliurus minor , eliurus , eliurus webbi , gymnuromys roberti , and nesomys rufus — as well as the black rat . at andohahela , monticolomys was found at an altitude of 1 , 875 m ( 6 , 152 ft ) in sclerophyllous forest . its distribution corresponds to the high mountain domain , a region defined on the basis of plant distributions . this region is now discontinuous , but the high mountain domain habitat was continuous from mountain to mountain as recently as the early holocene . subfossil remains of monticolomys have been found in mahajanga province ( northwestern madagascar ) . monticolomys koopmani is morphologically uniform across its wide distribution . monticolomys is nocturnal and solitary and produces litters of up to three offspring . it is scansorial , spending time on the ground but also climbing in vegetation . in andringitra , two specimens were captured on a liana 2 m ( 6 . 6 ft ) over the ground , and a third was caught on the ground together with two shrew tenrecs ( microgale ) . all five specimens from andohahela were trapped on the ground , as was the specimen caught in ankaratra in 1996 . its diet includes fruits and seeds ; in captivity , it eats fruits . conservation status as monticolomys koopmani is now known to be a widespread , common species occurring in at least one protected area ( andringitra national park ; it may also occur in ankarana special reserve ) , it is listed on the iucn red list as " least concern " . however , fires pose a threat in montane forest and , at lower elevations , its habitat is being converted into agricultural land .