A review of the taxonomy and fossil record of non-Protostegidae sea turtles from Cretaceous
Bibliographic record
Abstract
Fossil records of sea turtles from Cretaceous are found mainly in the clade Pan- Chelonioidea, but it also refers to a few species without a definitive phylogenetic relationship, currently considered Eucryptodira Indeterminate. The oldest record of Pan-Chelonioidea dates from the Aptian (Early Cretaceous) from Germany, which challenges the current hypothesis of the American origin for Americhelydia (Pan- Chelonioidea+ Chelydroidea) during the Campanian (Late Cretaceous). The records of Cretaceous marine turtles from the Old Word are scarce, but the distribution of stem Chelonioidea in North America were very abundant, following the coast of the Western Interior Seaway from Canada to south USA. All species of Pan-Chelonioidea from Cretaceous possessed limbs modified into paddles as adaptation for the marine environment, which allowed them to colonize small and large bodies of water. Their diet was variable, and the jaw specializations to shear and crush the food are present since the Late Campanian in stem Chelonioidea. Among the 45 named non- Protostegidae marine turtles from Cretaceous, 21 are nomina valida of Pan- Chelonioidea, 8 are nomina valida of Eucryptodira, 12 are nomina invalida, 5 are nomina nuda, 6 are nomina dubia, and 1 are nomen vanum.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.008 | 0.010 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".