Supplementary Table 1. Detailed data for specimens included in this study. All specimens are lower fourth premolars (p4s) from the collections of the University of California Museum of Paleontology (UCMP). Locality and specimen numbers are UCMP numbers.

Genus / species / NALMA / Spec. # / Loc. # / Formation / County / State
Mesodma / formosa / Lancian / 47025 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 47011 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 45795 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 45726 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 46407 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 45722 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 47208 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 45724 / V5620 / Lance / Niobrara / WY
Mesodma / formosa / Lancian / 115931 / V73087 / Hell Creek / Garfield / MT
Mesodma / formosa / Lancian / 187938 / V99220 / Hell Creek / Garfield / MT
Mesodma / formosa / Lancian / 187898 / V99220 / Hell Creek / Garfield / MT
Mesodma / formosa / Puercan 1 / 150117 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150116 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150121 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150120 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150119 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150118 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150124 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150123 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150122 / V65127 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150111 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150110 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150109 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150108 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150115 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150114 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150113 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150112 / V71203 / Tullock / McCone / MT
Mesodma / formosa / Puercan 1 / 150104 / V72210 / Tullock / Garfield / MT
Genus / species / NALMA / Spec. # / Loc. # / Formation / County / State
Mesodma / formosa / Puercan 1 / 150103 / V72210 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 150102 / V72210 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 116875 / V74110 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 150107 / V74111 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 150106 / V74111 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 116636 / V74111 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 116626 / V74111 / Tullock / Garfield / MT
Mesodma / formosa / Puercan 1 / 187532 / V96268 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 150086 / V65127 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150085 / V65127 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150079 / V65127 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150088 / V70199 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150087 / V70199 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150092 / V70201 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150091 / V70201 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150090 / V70201 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150089 / V70201 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150097 / V71203 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150096 / V71203 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150095 / V71203 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150094 / V71203 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150093 / V71203 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 150098 / V71203 / Tullock / McCone / MT
Mesodma / garfieldensis / Puercan 1 / 116621 / V74111 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 150099 / V74111 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 150100 / V74111 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 116635 / V74111 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 116622 / V74111 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 150101 / V77087 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 187529 / V96268 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 187512 / V96268 / Tullock / Garfield / MT
Mesodma / garfieldensis / Puercan 1 / 186794 / V96268 / Tullock / Garfield / MT
Genus / species / NALMA / Spec. # / Loc. # / Formation / County / State
Mesodma / garfieldensis / Puercan 1 / 186796 / V96268 / Tullock / Garfield / MT
Mesodma / hensleighi / Lancian / 51461 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 47191 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 51746 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 51856 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 45727 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 51749 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 47202 / V5620 / Lance / Niobrara / WY
Mesodma / hensleighi / Lancian / 185868 / V73087 / Hell Creek / Garfield / MT
Mesodma / hensleighi / Lancian / 115930 / V73087 / Hell Creek / Garfield / MT
Mesodma / hensleighi / Lancian / 174209 / V75162 / Hell Creek / Garfield / MT
Mesodma / hensleighi / Lancian / 153522 / V84130 / Hell Creek / Garfield / MT
Mesodma / hensleighi / Lancian / 187723 / V99230 / Hell Creek / Garfield / MT
Mesodma / hensleighi / Puercan 1 / 150084 / V77087 / Tullock / Garfield / MT
Mesodma / thompsoni / Lancian / 47217 / V5620 / Lance / Niobrara / WY
Mesodma / thompsoni / Lancian / 108053 / V72212 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 116604 / V73087 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 116605 / V74116 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 174275 / V75178 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 187559 / V75178 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 137546 / V75178 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 153516 / V77130 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 168712 / V77130 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 168710 / V77130 / Hell Creek / Garfield / MT
Mesodma / thompsoni / Lancian / 156129 / V80092 / Hell Creek / Garfield / MT