Selachian fauna from the Upper Cretaceous Dalton Sandstone, middle Rio Puerco Valley, New Mexico
— Sally C. Johnson and Spencer G. Lucas

Three localities in the Coniacian Dalton Sandstone along the Rio Puerco in Bernalillo County, New Mexico, yield numerous
teeth of selachians in addition to other vertebrate fossils. The selachian fauna is composed of Scapanorhynchus raphiodon, Squalicorax kaupi, Pseudohypolophus mcnultyi, Ptychotrygon triangularis, Ischyriza mira, Cantioscyllium decipiens, Squatina sp., Hybodus cf. H. butleri and Ptychodus mortoni. Pseudohypolophus and Scapanorhynchus are the dominant selachian taxa from these localities. Taxonomic composition does not vary between the Dalton selachian localities, but the percentages of taxa present do vary. These differences are most likely due to hydraulic sorting by currents and by storm action.