On a diverse tetrapod ichnofauna from early Permian red beds in San Miguel County, north-central New Mexico
— S. Voigt and S. G. Lucas

Late Paleozoic red beds of the Sangre de Cristo Formation and overlying Yeso Group in San Miguel County in north-central New Mexico are locally rich in fossil tetrapod footprints. The largest public collection houses about 200 specimens with tetrapod footprints from 16 different localities within the study area. The assemblage includes tracks of Batrachichnus (Woodworth, 1900), Limnopus (Marsh, 1894), Ichniotherium (Pohlig, 1892), Tambachichnium (Müller, 1954), Dimetropus (Romer and Price, 1940), and Dromopus (Marsh, 1894). Less well recorded are tracks that are compared with Matthewichnus (Haubold, 1970), Notalacerta (Butts, 1891), and Hyloidichnus (Gilmore, 1927). This diverse ichnofauna is referred to as microsaur, temnospondyl, diadectomorph, eupelycosaur, non-diapsid eureptile (‘captorhinomorph’) and parareptile or diapsid eureptile trackmakers. In most cases, the track-trackmaker correlation is well supported by tetrapod body fossil remains from closely associated beds of the Sangre de Cristo Formation. Based on vertebrate tracks, the upper part of the Sangre de Cristo Formation in the study area is suggested to be of late Early Permian (late Artinskian/late Wolfcampian) age.