ALBIAN AMMONITE FAUNAS FROM PERU: THE GENUS NEODESHAYESITES CASEY, 1964

Abstract

Our understanding of the Cretaceous ammonite succession of Peru is mainly based on the reference work of Benavides Caceres (1956) that updates the descriptive paleontological papers by Gabb (1877), Sommermeier (1910), and Knechtel et al. (1947), among others. New fossil collections made in the course 1995 and 1999 in northern and central Peru provide the basis for a revision of the Albian ammonite faunas of this country. In contrast to our predecessors, our collections are based on sections that have been sampled bed by bed. The present study concentrates on the Early Albian ammonites from the Inca Formation of northern Peru. These forms were previously described as Parahoplites nicholsoni Benavides Caceres, 1956, P. inti Benavides Caceres, 1956, and P. quilla Benavides Caceres, 1956. Comparison of the Peruvian specimens with material from Colombia has convinced us that these taxa should be placed in Neodeshayesites Casey, 1964. As interpreted herein, Neodeshayesites is a representative of Acanthohoplitinae that also includes species from Texas previously assigned to Hypacanthoplites Spath, 1923 and Parahoplites Anthula, 1899 (Scott, 1940; Young, 1974). The paleogeographic distribution of the genus is restricted to the New World and includes Colombia, Venezuela, Texas, and Peru. The newly collected Neodeshayesites come from the Banos del Inca and Tamberia Oeste sections in the department of Cajamarca in northern Peru. The first section is situated north of Banos del Inca, 10 km east of the city of Cajamarca, in the direction of Quebrada Otuzco. The second lies northwest of Algodon, near the Hacienda Tamberia, 20 km west of Aguas Calientes and near the junction of the Cajamarca and Crisnejas rivers (Fig. 1). Figure 1 —Map of geographic positions of the Banos del Inca and Tamberia Oeste localities. Details extracted from the 1/250,000 Topographic Map of …