Late Cretaceous (Maastrichtian) Chondrichthyes and Osteichthyes from northeastern Iberia

- A diverse ichthyofauna inhabited the coastal and fluvial settings of the southern Pyrenees throughout the Maastrichtian.
- The oldest records for Osteoglossidae and Perciformes in Europe are reported.
- The oldest evidence of Cypriniformes worldwide is reported.
- The southern Pyrenees record may represent a good example of the ichthyofaunal turnover during the Late Cretaceous.
- The Maastrichtian icthyofauna from the southern Pyrenees reveals Asian and North American biogeographical affinities.

Intensive sampling for vertebrate microfossils has yielded abundant fish remains in the Maastrichtian units of the Tremp Formation (southern Pyrenees, Catalonia, Spain). Samples were taken from eight new sites representing different palaeoenvironments including coastal wetlands and floodplains, in order to assess the fish diversity and to gain a better understanding of the last dinosaur-dominated ecosystems of northeastern Spain. The results suggest that a diverse ichthyofauna inhabited these transitional to inland fluvial settings throughout the Maastrichtian, comprising both marine and freshwater taxa. Three different chondrichthyans, eight basal neopterygians and at least seven teleostean species were found, the latter being more diverse than in other Maastrichtian localities in Europe. Fossil evidence from the studied late Maastrichtian assemblages suggests that teleosteans were present in all the trophic guilds. In addition, the oldest records for osteoglossids and perciforms in Europe, as well as for cypriniforms worldwide, are reported here. The findings from the southern Pyrenees also reveal ichthyofaunal turnover during the Late Cretaceous, with 'holosteans' being replaced by teleosteans. Moreover, Maastrichtian ichthyofaunas from the southern Pyrenees show Asian and North American biogeographical affinities.