The first skull of<i>Sivameryx africanus</i>(Anthracotheriidae, Bothriodontinae) from the early Miocene of East Africa
Bibliographic record
Abstract
Here we describe the first known skull and associated postcrania of the small bothriodontine anthracotheriid Sivameryx africanus, which fills an important gap in the current knowledge of morphological diversity within the Anthracotheriidae of Africa. The skull was recovered from the latest early Miocene sediments of the Kalodirr Member in the Turkana Basin of Northern Kenya, and the age is well constrained between two tephra dated to 17.5 ± 0.2 and 16.8 ± 0.2 Ma. A partial mandible of Sivameryx from Kalodirr is also described because it may belong to the same individual. The new anatomical data were incorporated into a genus-level phylogenetic analysis of Bothriodontinae that reveals that Sivameryx is the sister taxon to Hemimeryx and belongs to a clade of advanced bothriodontine anthracotheriids alongside the genera Merycopotamus, Libycosaurus, and Afromeryx. The new material of Sivameryx from Kalodirr greatly expands our knowledge of the cranial anatomy of the genus, because the skull of Sivameryx does not reveal any specializations for aquatic habitats, such as those seen in Libycosaurus. Here we suggest, based on the preserved cranial and postcranial evidence, that Sivameryx may have been a small browser that inhabited denser stands of vegetation at Kalodirr based on evidence from its narrow snout and well-developed labial musculature. However, its masticatory muscles were also relatively well developed, suggesting repetitive loading of the jaw when chewing tough vegetation.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".