Examination of the subarticular tubercles in Ptychohyla reveals considerable intraspecific variation.
"A Review of the Middle American Tree Frogs of the Genus Ptychohyla"
William E. Duellman
intraspecific variation in the subgenus Neotamias is slight, consisting of differences in size.
"Genera and Subgenera of Chipmunks"
John A. White
11210 is not extreme and does not exceed the range of intraspecific variation that could be expected for this element of the dentition.
"Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan"
William A. Clemens