Vampyravus orientalis Schlosser (Chiroptera) from the Early Oligocene (Rupelian), Fayum, Egypt — Body Mass, Humeral Morphology and Affinities
Bibliographic record
Abstract
Vampyravus orientalis, from the Oligocene of Fayum, Egypt was the first fossil bat described from Africa. It is represented by a single, relatively large humerus from an unknown horizon in the Jebel Qatrani Formation. Based on regression analyses of skeletal proportions of modern bats, we developed a set of equations to estimate body mass of fossil bats from known skeletal elements in order to test the hypothesis that Vampyravus could have been within the body size range of other Fayum bats, including several recently described taxa from the Jebel Qatrani and underlying Birket Qarun Formations. Our findings indicate that only Witwatia could have had a body mass similar to Vampyravus. Witwatia is known only from Quarry BQ-2 (Late Eocene, Priabonian) in the Birket Qarun Formation. Therefore Vampyravus is between 2 and 7 million years younger, depending on where within the Jebel Qatrani Formation it was found. Also, a recently discovered distal humerus of Witwatia from BQ-2 demonstrates that this taxon differs substantially from Vampyravus in comparable morphology. Vampyravus is distinct from all other Fayum fossil bats. Vampyravus shares characteristics of the proximal and distal humerus with several extant bat groups including phyllostomids, some rhinolophoids, natalids, emballonurids, and rhinopomatids. The latter two families are represented by fossil forms in the Fayum. Although Vampyravus is much larger than either the Fayum emballonurid or rhinopomatid, relatively large size typifies many taxa representing modern bat groups in the Fayum, making it all the more conceivable that Vampyravus could belong to one of these families.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".