2025/01/30 by Kevin L. Gomez, Diego Pol, Martín D. Ezcurra +1 · 1 voice · 1 citation
Earth and Planetary Sciences · #Paleontology and Evolutionary Biology #Evolution and Paleontology Studies #Paleontology and Stratigraphy of Fossils
paper · doi:10.1111/cla.12607
openalex publication_date 2025/01/30 · openalex created_date 2025/02/01 · openalex updated_date 2026/07/31
Since their origin, sauropodomorphs have undergone numerous anatomical changes from small and bipedal early sauropodomorphs towards massive-bodied and quadrupedal sauropods. However, the timing of these changes in the evolution of the group is unclear. Here, we describe the appendicular skeleton of the early diverging eusauropod Bagualia alba from the late Early Jurassic of Patagonia, Argentina, and conduct a morphological disparity analysis based on a phylogenetic dataset of Sauropoda. The results reveal a change in morphospace occupation between the pre-Toarcian and Toarcian-Middle Jurassic sauropodomorphs and between the latter and Late Jurassic forms. The first shift corresponds with the extinction of non-sauropodan sauropodomorphs and the diversification of sauropods, while the second corresponds with the diversification of Neosauropoda and closely related eusauropods (mamenchisaurids, turiasaurians) in the Late Jurassic, leading to a substantial shift and increase in morphological disparity. Finally, we found that body mass is significantly correlated with the first principal coordinate axis of the morphospace in two-thirds of a random sample of optimal trees, which suggests that body size played a role in shaping the evolution of sauropod morphology. In this context, Bagualia provides insights into the evolution of Sauropoda, particularly regarding changes that occurred during the Early to Middle Jurassic.