Deep-sea Ordovician lingulide brachiopods and their associated burrows suggest an early colonization of proximal turbidite systems
Bibliographic record
Abstract
Trace fossils from Ordovician deep-marine environments are typically produced by a shallow endobenthos adapted to live under conditions of food scarcity by means of specialized grazing, farming, and trapping strategies, preserved in low-energy intermediate to distal zones of turbidite systems. High-energy proximal zones have been considered essentially barren in the early Paleozoic. We report here the first trace and body fossils of lingulide brachiopods in deep-marine environments from an Upper Ordovician turbidite channel-overbank complex in Asturias, Spain. Body and trace fossils are directly associated, supporting the interpretation of a lingulide tracemaker. Ellipsoidal cross-section, cone-in-cone spreite, and spade morphologies suggest the specimens belong to Lingulichnus verticalis. The oblique orientation in both trace and body fossils is the result of tectonic deformation. The organisms were suspension feeders showing escape, dwelling, and equilibrium behaviours controlled by sedimentation rates associated with turbidite deposition. These trace fossils and their in situ producers represent the oldest evidence of widespread endobenthos colonization in high-energy, proximal areas of turbidite systems, expanding the bathymetric range of Lingulichnus and the variety of behaviours and feeding styles in early Paleozoic deep-marine environments.
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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 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".