Upper Jurassic (Tithonian) belemnites from the Neuqu´en Basin, Argentina

Abstract

Belemnites were a group of Mesozoic coleoids with a global distribution from the Early Jurassic to the Late Cretaceous. During the Late Jurassic–Early Cretaceous, Gondwana’s marine shelves were dominated by Belem­ nopsis and Hibolithes populations. In contrast to the Austral Basin, where both genera are quite common, their record in the Neuqu´en Basin (Argentina) is rather scarce and poor, probably due to a combination of locally unfavorable environmental conditions and predation pressure. Here we describe a new belemnite association from the Tithonian of the Vaca Muerta Formation from southern Mendoza and northern Neuqu´en provinces. Belemnite’s findings are assignable to the Tithonian Windhauseniceras internispinosum and Corongoceras alternans Andean ammonoid Biozones. The studied rostra are identified as Belemnopsis cf. B. patagoniensis, Belemnopsis cf. B. launceloti, and Hibolithes argentinus? Affinities of the Neuqu´ en Basin belemnite fauna are referred to the Madagascan-Eastern Africa associations (Ethiopian Subprovince, Tethyan Province), adding evidence to an established Trans-Gondwana seaway enabling the connection between those areas from the Tithonian onwards.