Order Rodentia - Family Sciuridae Author Wilson, Don E. Author Reeder, DeeAnn text 2005 The Johns Hopkins University Press Baltimore Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 2 754 818 book chapter 0-8018-8221-4 10.5281/zenodo.7316535 Spermophilus (Spermophilus) pygmaeus subsp. mugosaricus Lichtenstein 1823 Synonyms: Spermophilus (Spermophilus) pygmaeus subsp. kazakstanicus (Goodwin 1935) ; Spermophilus (Spermophilus) pygmaeus subsp. nikolskii ( Heptner 1934 ) .