Zulma Brandoni de Gasparini

Marta S. Fernandez

Academic paper

Paludicila

5

4

230-241

The South American record of Jurassic marine reptiles complements the northern hemisphere record both geographically and stratigraphically. Middle Jurassic marine reptiles fill a gap from the Aalenian to the early Callovian, when the records are scarce or absent elsewhere. Early Bajocian ichthyosaurs from the Neuquén Basin document the co-occurrence of nonophthalmosaurids and ophthalmosaurids and include the oldest record of Ophthalmosauridae. Similarly, the record of South American metriorhynchids is older than that of Europe. The oldest Metriohrynchus in Chile is early Bajocian, whereas in Europe, it is early Callovian. Metriohrynchus aff. M. brachyrhynchus in northwestern Patagonia is late Bathonian whereas the oldest M. brachyrhynchus in Europe is early Callovian. Early-Middle Jurassic plesiosaurs are extremely scarce worldwide, and Maresaurus from the early Bajocian represents almost the only plesiosaur of this age. The highest abundance and taxonomic diversity, however, occurs in the Late Jurassic (Tithonian) of the Neuquén Basin and includes pleurodiran and cryptodiran turtles (Notomemys laticentralis and Neusticemys neuquina), ophthalmosaurid ichthyosaurs (Caypullisaurus bonapartei, Ophthalmosaurus sp. and Aegirosaurus sp.), pliosaurs (Pliosaurus sp., Liopleurodon sp.) and metriorhynchids (Metriorhynchus sp., Geosaurus araucanensis and Dakosaurus andiniensis). Jurassic marine reptile faunas from the Southeastern Pacific are closely related to Western Tethyan faunas. These close similarities can be explained in terms of a marine connection (Caribbean seaway) between both areas. The Caribbean seaway (�Hispanic Corridor�) played an important role for dispersion of marine reptile since the Middle Jurassic, or even before. Toward the end of the Jurassic in the European Tethys, mass extinctions diminished the diversity of marine reptiles. However, in the Southeastern Pacific (Argentina and Chile) no evidence suggests massive extinctions, at least in the record of marine reptiles.

English