Late Furongian trilobites from the Quebrada Oblicua, San Isidro area, Mendoza, Argentina

Abstract

The trilobites from the “Hungaia puelchana Zone” (=Saukia Zone) of the San Isidro area (Mendoza, western Argentina) were briefly described by Carlos Rusconi in the 1950s, and since then they have been cited frequently in the literature but not fully revised. Large numbers of specimens from late Cambrian allochthonous carbonate blocks (La Cruz Olistolith) of the Quebrada Oblicua are available in the Ángel Borrello collections of the Museum of Natural Sciences of La Plata, Argentina. On the basis of this material, Micragnostus pehuenchensis (Rusconi), Hungaia puelchana Rusconi and Rasettia crucensis (Rusconi) are redescribed herein. In addition, Phoreotropis Raymond and Tatonaspis Kobayashi are reported from the Argentine Precordillera for the first time. The fauna studied has a clear Laurentian aspect and is assigned to the Upper Sunwaptan (upper Furongian).