2026-01-05
Christophe Hendrickx, Matías Soto Núñez, Ricardo Araújo, Jorge Gustavo Meso, Simone Maganuco, Adé Ben-Salahuddin
Abelisauridae were medium to large-bodied carnivorous dinosaurs with short, ornamented skulls, poorly recurved ziphodont teeth, and reduced forelimbs. They were the dominant terrestrial carnivores in many Gondwanan ecosystems during the Cretaceous. Their Jurassic origin, primarily based on the putative abelisaurid Eoabelisaurus from the Early Jurassic of Patagonia, remains debated, with many authors considering Abelisauridae as a strictly Cretaceous theropod radiation. Here, we describe several historically and stratigraphically important isolated theropod teeth from Gondwana, identified as belonging to abelisaurids using new cladistic and machine learning methods. Dental evolution in Abelisauridae was additionally explored using an updated version of a dentition-based data matrix focused on ceratosaurs. Results of this study show that the evolution of the dentition in abelisaurids was marked by a decrease in size of the mesialmost dentary teeth and the displacement of the tallest crowns towards the middle part of the maxilla. Two isolated abelisaurid teeth from the Late Cretaceous of India and Patagonia were also identified as the earliest published record of a non-avian theropod in Asia and an abelisaurid in Argentina, respectively. More importantly, isolated theropod teeth confidently referred to Abelisauridae from the Middle Jurassic of Madagascar provide additional support for the emergence of this clade in Gondwana before the Late Jurassic and reveal that the acquisition of abelisaurid dental traits occurred early in the evolutionary history of one of the most successful radiations of non-avian theropods from Europe and the Southern Hemisphere.
2026-01-05
Chris Barker, Darren Naish, Neil Gostling
The recent description of putative spinosaurid teeth from the latest Cretaceous (Campanian–Maastrichtian) of Peru by Olmedo- Romaña et al . (2025) has interesting implications for our understanding of these atypical dinosaur predators. Such a late occurrence of the clade would require a temporal range extension of some 15 million years, suggesting they survived the currently enigmatic faunal turnover events experienced during the “mid”-Cretaceous and persisted for some time beyond the Cenomanian. This commentary reviews the taxonomic affinities of these specimens. We demonstrate that their morphology is inconsistent with spinosaurid dentition and that they lack key characters exhibited by the clade, with our revised interpretation instead favouring crocodylomorph affinities for these specimens. Accordingly, we urge caution in the interpretation of conidont tooth morphologies given that multiple semi-aquatic and aquatic amniote lineages independently converged on this dental morphotype. Spinosaurids did not, therefore, survive into the latest Cretaceous and instead appear to go extinct around the Cenomanian–Turonian boundary, the drivers of which remain unclear.
2026-01-05
Erik Isasmendi, Elisabete Malafaia
Abelisaurids were medium- to large-bodied theropods that inhabited Gondwana and Europe, even becoming the apex predators in the latest Cretaceous ecosystems of many of these areas. European abelisaurids remain elusive, but their remains are becoming increasingly abundant in the Upper Cretaceous Ibero-Armorica. In this work, systematic, morphometric, and cladistic analyses of tooth samples from the Campanian–Maastrichian deposits of three localities (Chera 2, Montrebei and Viso) from the Iberian Peninsula have allowed these elements to be reassigned to abelisaurids. The specimen from Chera 2 is assigned to Arcovenator sp. whereas teeth from Montrebei and Viso are classified as Abelisauridae indet. The latter represents the first confirmed abelisaurid remain from the Cretaceous of Portugal. The axial remains identified as belonging to Rhabdodon from Laño are here attributed to cf. Arcovenator . These findings indicate that abelisaurids were the only apex terrestrial predators and among the most abundant theropods in the Upper Cretaceous of the Ibero-Armorican landmass. The reclassification of mid- to large-sized isolated teeth from Ibero-Armorica as abelisaurids, rather than carcharodontosaurids or closely related forms, suggests that Abelisauridae had already become the dominant apex theropod lineage by the Cenomanian. The abelisauroid fossil record in Ibero-Armorica spans from the Albian to the latest Maastrichtian, indicating a complex and temporally extensive presence. Despite most of the specimens being fragmentary, the available evidence supports the persistence and diversification of abelisaurids across Ibero-Armorica, with multiple lineages arising either from a possible Albian stock or resulting from successive dispersals, followed by insular diversification throughout the Late Cretaceous.
2026-01-05
Harold Jiménez, Martín Ezcurra, Martín Hechenleitner, Giorgio Basilici, Agustín Martinelli, Lucas Fiorelli
Abelisauridae is a group of ceratosaurian theropods that thrived mainly in Gondwana during the Cretaceous. Their fossil record is currently represented by more than 25 species, and their most complete and abundant records are from the Argentinean Patagonia. Outside Patagonia, the record of named Argentinean ceratosaurians has been limited to the Cretaceous of the Salta Province, with the noasaurid Noasaurus –represented by a fragmentary skeleton–and the brachyrostran abelisaurid Guemesia –represented by a nearly complete braincase and partial skull roof–. Here, we report a new abelisaurid theropod specimen (CRILAR-Pv 506) from the Late Cretaceous of La Rioja Province, northwestern Argentina. It was found at the Tama locality, in outcrops of the Campanian Los Llanos Formation, and associated with titanosaurian sauropod remains. The new abelisaurid specimen is represented by a first dorsal centrum, a second dorsal vertebra, a partial sacrum, left ilium, pubis and ischium, and other indeterminate elements. A unique combination of character states led us to propose the new genus and species Vitosaura colozacani . Phylogenetic analyses found Vitosaura either as a non-brachyrostran abelisaurid, closely related to Indo-Malagasy species in some trees, or a non-carnotaurinin furileusaurian. However, the interrelationships among abelisaurids are poorly supported. Our comparisons confirm the presence of abelisaurids in the Los Llanos Formation and this is the first named theropod taxon in the Cretaceous of La Rioja Province.