Xenarthran dental microstructure and dental microwear analyses, with new data for<i>Megatherium americanum</i>(Megatheriidae)
Bibliographic record
Abstract
Xenarthran teeth are rootless and continuously growing. They lack an outer enamel layer and consist instead of a combination of 2 generally different varieties of dentine with or without an outer collar of cementum. This dental make-up is unique among mammals. In the last decade, xenarthran teeth have been subject to a number of studies regarding microscopic features, including analyses of microstructure and microwear patterns. Here, we present a review of the present knowledge in these 2 fields together with new results on feeding adaptations in the giant ground sloth, Megatherium americanum. Microwear patterns suggest that M. americanum fed mainly on plants with low to moderate intrinsic toughness, although we observe a trend that microwear patterns in extinct sloths may reflect habitat (i.e., feeding in open habitats with higher amounts of grit versus closed habitats with lower amounts of grit) as much as, if not more than, the texture of ingested food. Los dientes Xenarthran no tienen raíz y permanecen en continuo crecimiento. Carecen de la capa de esmalte exterior y consisten en una combinación de dos variedades generalmente diferentes de dentina con o sin un collar exterior de cemento. Este patrón dental es único entre los mamíferos. En la última década, los dientes xenarthran han sido objeto de estudio en relación a las características microscópicas, incluyendo análisis de los patrones de microestructura y microdesgaste. A continuación presentamos una revisión de los conocimientos actuales en estos 2 campos, y nuevos resultados sobre adaptaciones de alimentación en el perezoso gigante, Megatherium americanum. Los patrones de microdesgaste encontrados sugieren que M. americanum se alimentaba principalmente de plantas con baja a moderada dureza intrínseca, aunque se observa una tendencia a que los patrones de microdesgaste en perezosos extintos siempre son un reflejo del hábitat (es decir, que se alimentan en hábitats abiertos, con una mayor cantidad de grano en comparación con los hábitats cerrados con cantidades más bajas de grano) tanto o más que la textura de los alimentos ingeridos.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".