Abelisauridae cranial ornamentation evolution (free pdf)
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Ben Creisler
Jun 24, 2026, 2:16:12 PM (2 days ago) Jun 24
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Ben Creisler
A new paper:
Free pdf:
Enzo Emanuel Seculi Pereyra, Ignacio Maria Soto & Damian Eduardo Perez (2026)
Beyond species recognition hypothesis: evolutionary trends in Abelisauridae cranial ornamentation
Paleobiology (advance online publication)
DOI: https://doi.org/10.1017/pab.2026.10099
https://www.cambridge.org/core/journals/paleobiology/article/beyond-species-recognition-hypothesis-evolutionary-trends-in-abelisauridae-cranial-ornamentation/A46ECEF6FC6E83CED8BEE4277B57BBD8
Abstract
Abelisaurid dinosaurs display a remarkable diversity in cranial ornamentation, which includes several features such as rugosities, pits and grooves on the rostrum and orbital regions, midline knobs, and paired plus sculptured structures across the skull roof. To investigate macroevolutionary patterns that underlie this diversity, we tested the “species recognition” hypothesis using phylogenetic comparative methods. Our results indicate directional and ordered evolutionary patterns in cranial ornamentation that are more consistent with expectations of sexual selection than with the stochastic patterns predicted under the species recognition hypothesis. Moreover, sympatric species exhibited highly divergent ornamentation, and the degree of surface texturing and the development of certain structures (e.g., knobs) increased through ontogeny. These findings suggest that cranial ornamentation in Abelisaurids was influenced by mechanisms of sexual selection, sexual dimorphism, or mutual selection. Evolutionary modeling combined with evidence from the fossil record and phylogenetic correlation analysis reveals that the ornamentation of the rostrum and orbital regions was evolutionarily coupled and became canalized during the Early Cretaceous. In contrast, phylogenetic correlation analyses demonstrated that skull roof ornaments and rostral and orbital ornaments evolved decoupled. Neither discrete ornament traits nor the accumulation of traits over time showed significant associations with body size, indicating that ornament diversification in Abelisauridae was not constrained by allometric trends. During the Late Cretaceous, after refined ecological specialization, the subclades Carnotaurini and Majungasaurinae underwent further elaboration, acquiring features such as a prominent midline knobs, paired structures, and reinforced occipital and cervical regions. These derived morphologies may have facilitated more complex sociosexual behaviors.
Non-technical Summary
Abelisaurid dinosaurs were a group of theropod carnivores that primarily inhabited the Southern Hemisphere during the Cretaceous Period. One of their most remarkable features is a striking variety of cranial ornaments, which included roughened areas on the snout and around the eyes, midline knobs, and paired structures such as the horn-like projections of Carnotaurus. However, the evolution of these features over time has remained largely unexplored. In this study, we investigated the evolution of these ornaments and what they might reveal about the social and sexual behaviors of abelisaurids. Our results indicate that ornamentation did not evolve randomly but followed specific directional patterns, with certain structures becoming fixed early in abelisaurid history. Surprisingly, body size and ornamentation evolved independently; larger species were not necessarily more ornamented. Later, during the Late Cretaceous, groups such as Carnotaurini and Majungasaurinae developed even more elaborate features, including bony knobs, paired projections, and reinforced skull regions, which may have been used for visual display or social interactions. Overall, our findings suggest that abelisaurid skull ornaments were shaped primarily by sexual selection, highlighting the significance of visual signaling in the evolution of these remarkable predators.
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Free pdf:
Enzo Emanuel Seculi Pereyra, Ignacio Maria Soto & Damian Eduardo Perez (2026)
Beyond species recognition hypothesis: evolutionary trends in Abelisauridae cranial ornamentation
Paleobiology (advance online publication)
DOI: https://doi.org/10.1017/pab.2026.10099
https://www.cambridge.org/core/journals/paleobiology/article/beyond-species-recognition-hypothesis-evolutionary-trends-in-abelisauridae-cranial-ornamentation/A46ECEF6FC6E83CED8BEE4277B57BBD8
Abstract
Abelisaurid dinosaurs display a remarkable diversity in cranial ornamentation, which includes several features such as rugosities, pits and grooves on the rostrum and orbital regions, midline knobs, and paired plus sculptured structures across the skull roof. To investigate macroevolutionary patterns that underlie this diversity, we tested the “species recognition” hypothesis using phylogenetic comparative methods. Our results indicate directional and ordered evolutionary patterns in cranial ornamentation that are more consistent with expectations of sexual selection than with the stochastic patterns predicted under the species recognition hypothesis. Moreover, sympatric species exhibited highly divergent ornamentation, and the degree of surface texturing and the development of certain structures (e.g., knobs) increased through ontogeny. These findings suggest that cranial ornamentation in Abelisaurids was influenced by mechanisms of sexual selection, sexual dimorphism, or mutual selection. Evolutionary modeling combined with evidence from the fossil record and phylogenetic correlation analysis reveals that the ornamentation of the rostrum and orbital regions was evolutionarily coupled and became canalized during the Early Cretaceous. In contrast, phylogenetic correlation analyses demonstrated that skull roof ornaments and rostral and orbital ornaments evolved decoupled. Neither discrete ornament traits nor the accumulation of traits over time showed significant associations with body size, indicating that ornament diversification in Abelisauridae was not constrained by allometric trends. During the Late Cretaceous, after refined ecological specialization, the subclades Carnotaurini and Majungasaurinae underwent further elaboration, acquiring features such as a prominent midline knobs, paired structures, and reinforced occipital and cervical regions. These derived morphologies may have facilitated more complex sociosexual behaviors.
Non-technical Summary
Abelisaurid dinosaurs were a group of theropod carnivores that primarily inhabited the Southern Hemisphere during the Cretaceous Period. One of their most remarkable features is a striking variety of cranial ornaments, which included roughened areas on the snout and around the eyes, midline knobs, and paired structures such as the horn-like projections of Carnotaurus. However, the evolution of these features over time has remained largely unexplored. In this study, we investigated the evolution of these ornaments and what they might reveal about the social and sexual behaviors of abelisaurids. Our results indicate that ornamentation did not evolve randomly but followed specific directional patterns, with certain structures becoming fixed early in abelisaurid history. Surprisingly, body size and ornamentation evolved independently; larger species were not necessarily more ornamented. Later, during the Late Cretaceous, groups such as Carnotaurini and Majungasaurinae developed even more elaborate features, including bony knobs, paired projections, and reinforced skull regions, which may have been used for visual display or social interactions. Overall, our findings suggest that abelisaurid skull ornaments were shaped primarily by sexual selection, highlighting the significance of visual signaling in the evolution of these remarkable predators.
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