Ontogenetic dietary shifts in North American hadrosaurids (Dinosauria: Ornithischia)
Bibliographic record
Abstract
Ontogenetic niche shifts, the phenomenon whereby animals change their resource use with growth, were probably widespread in dinosaurs, but most studies of duck-billed dinosaur ontogeny have so far focused mainly on the development of the cranial ornamentation. Here, we quantify allometry of 13 ecomorphological variables of the skull and examine tooth microwear in a sample of North American hadrosaurids to better understand their ecological functioning with growth. Our results indicate that, consistent with the Jarman-Bell principle relating body size to fibre intake and feeding selectivity, juvenile hadrosaurids were relatively more selective than their adult counterparts and subsisted on softer, low-growing browse cropped using lateral rotations of the neck. Chewing movements of the jaw probably did not differ greatly between growth stages. Our findings invite further investigation relating to cranial ontogenetic allometry in hadrosauromorphs more broadly, and to the possible role of ontogenetic niche shifts in the size structuring of Late Cretaceous herbivore communities.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".