Basisphenoid and basioccipital pits in microchiropteran bats
Bibliographic record
Abstract
We examined 686 skulls of 420 species of microchiropteran bats in 16 families to assess variation in pits in the basisphenoid and basioccipital bones. A total of 26 measurements were used to describe variation in pits, and patterns in the distribution of pits were examined across the families. Pits were absent from 154 species and present in 266 species. While some species had as many as four basisphenoid pits, basioccipital pits, when present, always occurred as a single pair. No species had more than four pits (basisphenoid or basioccipital and basisphenoid) in total. In some families all species either had pits (e.g. Emballonuridae) or none had pits (e.g. Rhinolophidae), but the incidence of pits usually was variable within families. The results of a cluster analysis of families based on the incidence of pits and morphological features of pits bore little resemblance to a recent phylogeny of Microchiroptera. A discriminant function analysis of features of pits of Emballonuridae, Phyllostomidae, Vespertilionidae and Molossidae correctly classified 66% of species to family revealing some continuity in pit structure among related species. There was no evidence of significant sexual dimorphism in the incidence or features of pits. Basisphenoid and basioccipital pits tended to increase in size with skull size. Neither the incidence nor the morphology of basisphenoid nor basioccipital pits was consistently associated with echolocation, diet or foraging behaviour. Pits were present or absent from species using either high-intensity or low-intensity echolocation calls, and the same was true of bats using high or low duty cycle modes of echolocation. Furthermore, the presence or absence of pits did not correspond to the presence or absence of harmonics in echolocation calls. We propose that basisphenoid and basioccipital pits are oscillators in the vocal tract and contribute to the production of non-linear phenomena in vocalizations made by bats.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".