Discovery of Upper Ladinian ammonoids at the type locality of the Lower Carnian Desatoyense Zone (South Canyon, New Pass Range, Nevada)

South Canyon, located in the New Pass Range in central Nevada (Fig. 1), is one of the most important localities for Upper Triassic marine invertebrates in North America. This site yields very rich ammonoid faunas, as well as cnidarians (Muller, 1936; Stanley, 1979; Roniewicz and Stanley, 1998), foraminifers (Gazdzicki and Stanley, 1983), bivalves (Waller and Stanley, 1998, 2005; Hopkin and McRoberts, 2003), and brachiopods.