New remains of the armored dinosaur Patagopelta cristata Riguetti et al. 2022 (Ornithischia, Parankylosauria) from the Late Cretaceous of Patagonia, Argentina

The fossil record of Southern Hemisphere thyreophorans has expanded significantly in recent years. Among notable discoveries is the armoured dinosaur Patagopelta cristata, from Maastrichtian beds in northeastern Patagonia. This taxon was described from disarticulated elements collected at ‘Salitral Moreno’ (Río Negro, Argentina), with a cervical half-ring designated as the holotype and additional materials from multiple individuals referred to it. However, the precise geographical provenance of these remains within the area is unknown. This contribution describes newly collected armoured dinosaur material from Salitral Moreno that provides key anatomical and phylogenetic information. The new material, comprising cranial elements, partial limbs, vertebrae, sacrum, pelvis, and osteoderms, is assigned to Patagopelta. These remains reveal a relatively plesiomorphic pelvis and an armoured tail resembling that of the parankylosaur Stegouros. Incorporation of these data into a comprehensive phylogenetic analysis places Patagopelta within Parankylosauria, closer to Antarctopelta and Kunbarrasaurus than to Stegouros. These findings support the interpretation of parankylosaurs as a distinct Southern Hemisphere radiation of thyreophorans, exhibiting greater body size, morphological, and likely ecological diversity than previously recognised.