HISTORY OF STUDY AND PERMIAN FOSSIL COLLECTIONS FROM PREHISTORIC TRACKWAYS NATIONAL MONUMENT, ROBLEDO MOUNTAINS, DOÑA ANA COUNTY, NEW MEXICO

The Robledo Mountains of southern New Mexico contain some of the world’s richest Permian fossil footprint localities. This fossil deposit, located on BLM land, has increased in global significance since one of us (JPM) made the initial discoveries of large in situ trackways in 1987. Continued exploration by JPM over the next 23 years has resulted in the discovery of more than 100 additional fossiliferous exposures of importance that in total represent one of the most complete Paleozoic trace fossil Lagerstätten known. The Robledo Mountains fossil deposit provides a unique look into the entire process of discovery, from the initial finds to the subsequent declaration in 2009 of the area as a National Monument, the Prehistoric Trackways National Monument (PTNM). The ichnologic fossil collection from the PTNM is now housed at the New Mexico Museum of Natural History and Science, Albuquerque. It preserves over 1000 cataloged specimens, from 14 localities, ranging in preservation from singleton tracks to trackways composed of dozens of individual footfalls. The breadth of ichnotaxa preserved is extensive, including both vertebrates (Batrachichnus salamandroides, Limnopus isp., Hyloidichnus bifurcatus, Dromopus agilis, Gilmoreichnus hermitanus, Dimetropus nicolasi and D. leisnerianus) and invertebrates (Augerinoichnus helicoidalis, Cochlichnus anguineus, Dendroidichnites irregulare, Diplichnites isp., Diplopodichnus biformis, Kouphichnium?, Lithographus hieroglyphicus, cf. Lockeia, Octopodichnus cf. O. didactylus, Palmichnium macdonaldi [holotype], P. palmatum, P. pottsae, Rotterodichnium major, Selenichnites belosis [holotype], cf. Spirorhaphe azteca, Stiallia pilosa, Stiaria intermedia, Striatichnium biflabellis, Tonganoxichnus apacheensis, T. buildexensis, T. robledoensis [holotype], Treptichnus bifurcus, Serpentichnus sigmoidalis [holotype] and taxa described in open nomenclature. The designation of the Robledo Mountains as a National Monument has stimulated renewed research interest in the area and its trace fossils.