A new small-bodied ankylosaurian dinosaur from the Upper Cretaceous of North Patagonia (Río Negro Province, Argentina)
Bibliographic record
Abstract
The most representative ankylosaurian remains from Argentina have been found in sediments of the Allen Formation (Campanian–Maastrichtian) in Salitral Moreno, Río Negro Province. Several authors have discussed the identity and history of these remains. In this study, we review all published material along with some new remains in order to summarize all the knowledge about these ankylosaurs. Previously published material includes a tooth, dorsal and anterior caudal vertebrae, a femur and several osteoderms. The new remains include synsacral and caudal elements, a partial femur and osteoderms. The anatomy of the tooth, the synsacrum, the mid-caudal vertebra, the femur and the osteoderms, and the histology of the post-cervical osteoderms, support a nodosaurid identification, as proposed in previous descriptions of the Salitral Moreno material. Patagopelta cristata gen. et sp. nov. is a new nodosaurid ankylosaur characterized by the presence of unique cervical half-ring and femoral anatomies, including high-crested lateral osteoderms in the half rings and a strongly developed muscular crest in the anterior surface of the femur. The ∼2 m body length estimated for Patagopelta is very small for an ankylosaur, comparable with the dwarf nodosaurid Struthiosaurus. We recovered Patagopelta within Nodosaurinae, related to nodosaurids from the ‘mid’-Cretaceous of North America, contrasting the previous topologies that related this material with Panoplosaurini (Late Cretaceous North American nodosaurids). These results support a palaeobiogeographical context in which the nodosaurids from Salitral Moreno, Argentina, are part of the allochthonous fauna that migrated into South America during the late Campanian as part of the First American Biotic Interchange.https://zoobank.org/urn:lsid:zoobank.org:pub:FBA24443-F365-49FD-A959-10D2848C2400
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".