The homology, form, and function of the microraptorine lateral pubic tubercle
Bibliographic record
Abstract
Microraptorine dromaeosaurids are characterized by a lateral pubic tubercle or process on the midshaft of the pubis. Initially proposed as a tubercle for muscle attachment, this structure has since received little attention beyond identifying its presence or absence in theropods. Examination of this tubercle reveals inconsistencies in texture and topology with attachment sites for pelvic musculature. However, its unevaluated homology precludes meaningful utilization in comparative or paleobiological studies. Here, the homology, form, and function of the lateral pubic tubercle are explored in the context of the extant phylogenetic bracket. This framework, combined with dissection of extant relatives and direct observation of osteological correlates in extant and extinct archosaurs, permits assessment of various tissues that are potentially associated with the microraptorine lateral pubic tubercles. Consideration of pelvic soft tissues reveals that these tubercles are most parsimoniously interpreted as an osteological correlate for pubogastralial ligaments, which anchor the most posterior row of gastralia to the hip in extant crocodylians. Homologous structures that are correlates for pubogastralial ligaments vary widely in morphology across archosaurs. A series of alterations occurred in paravian theropods while undergoing pubic retroversion and ventilatory changes. The relationship between the lateral pubic tubercles and the pubic apron also imposed functional consequences on surrounding tissues, most notably locomotory musculature arising from the pubic apron. This elucidates why the lateral pubic tubercle is only expressed in Microraptorinae.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".