 Nesomys narindaensis is known from a damaged skull , missing part of the back , a mandible ( lower jaw ) with the first two molars ( m1 and m2 ) , and four isolated molars ( one first upper molar , M1 , one third upper molar , M3 , and two m2 ) . It is larger than each of the three living species , and the known material additionally differs from those in a few details that may not hold in larger samples . Total skull length is 61 @.@ 3 mm , longer than in the largest living species , N. lambertoni ( 50 @.@ 3 – 53 @.@ 8 mm ) . The width of the palate between the M1 is 8 @.@ 7 mm ( 7 @.@ 2 – 7 @.@ 9 mm in N. lambertoni ) and the length of the upper toothrow is 9 @.@ 04 and 9 @.@ 16 mm on the two sides of the skull ( 7 @.@ 2 – 7 @.@ 9 mm in N. lambertoni ) . 
