Search

Notosuchians are a crocodyliform clade with a rich Gondwanan fossil record, especially in Cretaceous South American deposits. More than half of all described species come from South America and, around one quarter, have been discovered in the Adamantina Formation (Bauru Group, Brazil). The large amount of notosuchian remains from this formation, along with its chronostratigraphic uncertainty, may be distorting notosuchian palaeodiversity estimates. In order to analyse how these factors could be biasing our interpretations, palaeodiversity estimates were performed excluding and including the Adamantina Formation occurrence data, as well as assigning them to the main age ranges that have been proposed for the formation (Turonian-Santonian and Campanian-Maastrichtian). Furthermore, as other factors might be influencing palaeodiversity fluctuations, a modelling approach was performed to assess which abiotic factors, sampling artefacts, or a combination of them, could be driving these palaeodiversity dynamics. The results showed that the Adamantina Formation is causing a Lagerstätte effect that is distorting palaeodiversity estimates and, depending on the age assigned to that formation, the tempo and magnitude of the maximum palaeodiversity reached during the Late Cretaceous substantially changes. The results also suggest that the temporal bias might affect palaeobiological reconstructions not only in notosuchians but also in other groups. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous outcrops of Armuña (Segovia Province, Spain) yielded relatively abundant material of vertebrates during prospection and excavation in the second half of the 1980s. However, little has been published on these remains. A new analysis of the specimens from this upper Campanian site reveals the presence of some clades in the site for the first time (e.g., Dortokidae, Anguimorpha, Mosasauroidea). Furthermore, the material of the clades previously recognized there has been reviewed and described in more detail, with some previous systematic attributions confirmed and others refuted. Consequently, a relatively high local diversity has been identified. New taxa (i.e., a member of Anguimorpha and a eusuchian crocodyliform) are identified in Armuña, coexisting with other taxa previously described in other sites from the Iberoarmorican Realm. The vertebrates from Armuña confirm that the fauna from the Upper Cretaceous of the Iberian Peninsula is composed of a mixture of European endemic clades and lineages shared with other continents such as North America (e.g., anguimorphs) and Africa (e.g., bothremydids). [ABSTRACT FROM AUTHOR]

The palaeontological area of Algora (Guadalajara Province, central Spain) provides the largest concentration of vertebrate macroremains for the Cenomanian of south-western Europe. The available faunal list for Algora, based on the analysis of scarce remains collected in geological surveys carried out more than thirty years ago, was never updated. Therefore, and despite the great potential of this site to reveal novel information about the composition of the vertebrate fauna from the base of the Upper Cretaceous in the continent, the previous determination of many of the taxa recognized there is identified here as inaccurate or erroneous (e.g., the identification of two actinopterygian fishes, a single crocodyliform, the helochelydrid turtle Helochelys danubina and carcharodontosaurid dinosaurs). Recent fieldwork campaigns have provided numerous remains, including those of clades poorly represented so far, as well as others hitherto unknown at this site. The new faunal list proposed here included the lepisosteoid Obaichthys africanus , the helochelydrid aff. Plastremys lata , the pleurodiran Algorachelus peregrina , an indeterminate elasmosaurid, a non-eusuchian neosuchian and a eusuchian crocodyliform, a likely abelisaurid theropod and a lithostrotian sauropod. The study of these taxa provides new information about the palaeobiogeography and temporal distributions of some lineages, and increases knowledge about the poorly-known transition between the Lower and the Upper Cretaceous faunas in Europe. This faunal replacement, in which several well-represented lineages in the uppermost Cretaceous were established, is recognized as strongly conditioned by climate changes that took place between the end of the Early Cretaceous and the beginning of the Late Cretaceous. • The largest European Cenomanian concentration of macrovertebrates comes from Algora. • Recent fieldwork campaigns in Algora have provided numerous remains. • The faunal list of the site is updated here. • Information about the Early to Late Cretaceous faunal transition is provided. • This replacement is recognized as strongly conditioned by climate changes. [ABSTRACT FROM AUTHOR]