Upper Cretaceous European theropod palaeobiodiversity, palaeobiogeography and the intra‐Maastrichtian faunal turnover: new contributions from the Iberian fossil site of Laño

Abstract

A total of 227 theropod teeth have so far been recovered from the upper Campanian Laño site (northern Iberian Peninsula). The teeth were studied for their qualitative and quantitative features. From the theropod sample found at Laño, seven morphotypes attributed to five taxa are identified: a medium to large abelisaurid (Arcovenator sp.) and four small coelurosaurians (Dromaeosauridae indet., Paraves indet., cf. Paronychodon sp. and cf. Richardoestesia sp.) Together with the ground bird Gargantuavis and a possible ornithomimosaur, the theropod fauna of Laño might be composed of two medium–large‐sized non‐avian theropods, four small‐bodied non‐avian theropods and a large terrestrial bird. This makes the Laño site the richest and most diverse latest Cretaceous theropod site in Europe. Furthermore, the Laño site and the Upper Cretaceous localities of Europe that have yielded theropod remains suggest that the medium–large‐sized theropods were abelisaurids or indeterminate theropods. The small theropods are more abundant, diverse and represented by different dromaeosaurids, Paronychodon, Richardoestesia or related forms, troodontids and, probably, by other paravians. Of the birds, enantiornithines, gargantuaviids and ornithurines are also common in the European Upper Cretaceous sites. The theropod assemblage of Laño, together with the taxa of other Upper Cretaceous sites, supports the idea that several theropod dispersal events took place during the Cretaceous. This resulted in a mixture of European endemic, Asiamerican and Gondwanan forms. This study also supports the hypothesis that the intra‐Maastrichtian faunal turnover that occurred in the Ibero‐Armorican landmass seems to have had no apparent effect on theropods.

14th Symposium on Mesozoic Terrestrial Ecosystems and Biota

“…Dental material previously described as "hadrosaurid" compares well to the hadrosauromorphs Jeyawati and Bactrosaurus, and the early diverging hadrosaurid Eotrachodon. Theropod teeth include indeterminate dromaeosaurs and tyrannosaurs as well as an unusual paravian crown remarkably similar to remains from the Campanian of Spain (Isasmendi et al, 2022). Teeth from both members attributable to the enigmatic paravian morphotaxon "Richardoestesia" are exceptionally numerous in the collection.…”

An Eudromaeosaurian Theropod from Lo Hueco (Upper Cretaceous. Central Spain)

“…and Dromaeosauridae indet. [18,74]. Some small-sized tooth crowns from this locality were first tentatively attributed to cf.…”

“…An abundant and diverse fossil record of continental vertebrates has been described in different Campanian-Maastrichtian localities from Spain, particularly in the Basque-Cantabrian and Iberian basins, in the north and center-east regions respectively (e.g., [18,22,37,44,72,73]). The paleontological locality of Chera, in Valencia (middle-upper Campanian), yielded a relatively abundant and diverse assemblage of vertebrates (e.g., [18,[73][74][75]). However, theropod dinosaurs are represented by scarce isolated teeth that were interpreted as belonging to Theropoda indet., Neoceratosauria indet.…”

“…Some small-sized tooth crowns from this locality were first tentatively attributed to cf. Pyroraptor [74], but they were more recently reinterpreted as belonging to an indeterminate dromaeosaurid [18]. Another Spanish paleontological locality, Armuña, in Segovia (upper Campanian) also provided abundant remains of different vertebrate groups, including a collection of materials attributed to theropod dinosaurs that are represented by some pedal phalanges, including two unguals, assigned to Theropoda indet.…”

“…The European Upper Cretaceous deposits have yielded an abundant record of dinosaurs and other continental vertebrates with a great number of sites discovered in the last decades (e.g., [1][2][3][4][5][6][7][8]). In this context, particularly relevant are the sedimentary units of the Ibero-Armorican domain, mainly distributed in the Lusitanian (Portugal), Iberian (central Spain), Pyrenees (north-eastern Spain and southern France), and Provence (southeastern France) basins, together with correlative sequences from Transylvanian landmasses, mainly in the Haţeg and Rusca Montană basins of Romania and scanter assemblages from equivalent successions of the Netherlands, Belgium, southern Germany, Slovenia, Bulgaria, Ukraine, and European Russia (e.g., [1,2,[9][10][11][12][13][14][15][16][17][18]). Unfortunately, the record of theropod dinosaurs in these levels is relatively scarce and mostly composed of fragmentary materials, challenging our interpretation about the evolutionary history of these faunas during the latest part of the Mesozoic in the European archipelago.…”