Appendicular morphology of <i>Mesenosaurus efremovi</i> and the earliest occurrence of a calcaneal tuberosity
Bibliographic record
Abstract
The Richards Spur locality in Oklahoma, U.S.A. is renowned for its diverse assemblage of early Permian terrestrial tetrapods, including the varanopid Mesenosaurus efremovi. Recent quarrying operations yielded numerous skeletal remains attributed to this taxon, including partially articulated cranial and postcranial remains with the latter being especially important given the comparatively minimal description in previous studies. The specimens used in this study, including a superbly preserved hindfoot, all represent approximately the same growth stage, and collectively reveal the morphology of the entire pelvis and hindlimb in unprecedented detail. CT data, analysed using the segmentation software Avizo, was utilised to examine the hindfoot specimen. As in other varanopids, the limb proportions of this predator are gracile, the bones being more slender than in the similarly well-known taxon Varanops. In addition, M. efremovi exhibits unique ankle morphologies including a highly robust astragalus with a massive transverse ridge and a medially oriented tibial articular surface, a pronounced lateral calcaneal tuberosity and an enlarged fourth tarsal. These likely diagnostic features of Mesenosaurus point to specialised lower limb design for rapid locomotion, and further confirms its close relationship to the middle Permian M. romeri from Russia and consequent temporal longevity of this varanopid genus.
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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 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 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".