Original paper
Comparison of Upper Triassic and Lower Jurassic gastropods from the Peruvian Andes (Pucará Group) and the Alps (Cassian Formation)
Bandel, Klaus
Palaeontographica Abteilung A Band 233 Lieferung 1-6 (1994), p. 127 - 160
56 references
published: Nov 22, 1994
Abstract
The gastropod fauna of the Late Triassic to Jurassic Pucará Group contains fewer taxa than that of the Upper Ladinian to Karnian Cassian Formation. While only a few species are closely related to each other, in both assemblages the general character of groups (genera and families) is similar and both Upper Triassic faunas differ from Paleozoic and later Mesozoic faunal assemblages. The Peruvian species with a slit in the shell are few in number and usually poorly preserved, while there are many species in the Alps. While Peruvian Trochomorpha differ from those of the Alps, the Neritimorpha show closer relationships to each other. The same systematic groups (i. e. families) of Caenogastropoda are presented by different genera and species in both faunal assemblages. Among the Heterostropha, mathildids and cylindrobullinids are closely related while other groups show little in common. The following new species from the Pucará Group are described: Cassianastraea stanleya, Cryptaulax variformatum, Ladinula peruviana, Rhynchocerithium peruvianum, and several species are revised. The continuity of a number of Triassic groups into the Jurassic is demonstrated. Upper Triassic faunas of Peru and northern Italy belong to two different faunal provinces which during Triassic time had very little direct connection to each other. Some species of the Pucará, in contrast, have relationships with the Jurassic of Europe. During Jurassic time faunal provinces had more contact with each other.
Keywords
gastropods • Upper Ladinian • faunal assemblages • Pucará Group • Peru • Cassian Formation • Alps • Italy