Reconstructing the Evolution of North American Gomphotheres (Mammalia, Proboscidea) through Craniomandibular Characters
Bibliographic record
Abstract
The family Gomphotheriidae is the “waste basket” of proboscidean groups. Widely accepted as paraphyletic, gomphotheres are characterized by bunolophodont molars and extreme morphological variability. In this thesis, I attempt to resolve the phylogenetic relationships among gomphotheres and other proboscidean lineages by employing a craniomandibular character matrix that excludes characters pertaining to the most variable part of proboscidean skulls, their teeth. Using a combined-evidence Fossilized Birth-Death model, I use morphological, molecular, and stratigraphic range data to generate a phylogenetic hypothesis of proboscidean evolutionary history. The resulting tree topology largely agrees with the results of craniodental trees on the organization of proboscidean families, including the paraphyletic nature of the Gomphotheriidae. I also find evidence that the “shovel tusked” Amebelodontidae may be polyphyletic and that some of the morphological variability attributed to the species Gomphotherium productum is the result of misidentification and ignorance of independent North American lineages.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".