Quantification of leg mobility in the Burgess Shale Olenoides serratus indicates functional differences between trilobite and xiphosuran appendages
Bibliographic record
Abstract
BACKGROUND: Euarthropod appendages are specialized for diverse roles including feeding, walking, and mating, which require precise morphologies and ranges of motion. Cambrian fossils preserve exceptional details of extinct euarthropod appendages that can illuminate their anatomy and ecology. However, fossils are typically restricted by small sample sizes or incomplete preservation, and thus functional studies of the appendages usually rely on idealized reconstructions. The Burgess Shale Olenoides serratus is unique among trilobites owing to the availability of numerous specimens with soft tissue preservation that allow us to quantify its appendages' functional morphology. RESULTS: We measured the range of motion of the legs in Olenoides serratus and the extant horseshoe crab Limulus polyphemus. Despite repeated ecological comparisons between trilobites and xiphosurans, we find significant differences in the appendages' mobility between these taxa, with Limulus showing greater flexibility between the podomeres. CONCLUSIONS: O. serratus legs have a more restricted range of motion relative to L. polyphemus, particularly in their distal region. Flexure between the protopodite played a critical role in allowing the endopodite to create known trilobite trace fossils and bring food toward the ventral groove.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".