Apodemus uralensis cimrmani, also known as Cimrman Ural field mouse, is a rare subspecies of Ural field mouse found only in the town of Žatec situated in the Ústí nad Labem Region, Czech Republic. It is the only endemic vertebrate species of the Czech Republic.[1]
Named after fictional Czech polymath Jára Cimrman, the remains of a distinct small species of mouse were found between 1974 and 1981 based on these findings, the mouse was described in 2002 as a new subspecies. It is considered as an isolated population of the more prevalent Ural field mouse both species are almost identical but the Cimrman mouse's skull is smaller in size due to biological adaptions. Distinguishing the two species is a difficult task even for experts.[2]
The population's distribution was confined to 25 localities of Žatec with considerable vegetation due to agriculture all within an area of 25x20km.