The ichnotaxonomy of vertically oriented, bivalve-generated equilibrichnia
Bibliographic record
Abstract
Bivalves have pursued an infaunal lifestyle since early in their history. Trace fossils that have been attributed to the infaunal activity of bivalves include Hillichnus, Lockeia (= Pelecypodichnus ), Lophoctenium, Protovirgularia, Ptychoplasma , Siphonichnus and Scalichnus . Re-evaluation of the ichnogenera Siphonichnus and Scalichnus supports consolidation into a single ichnogenus, Siphonichnus , which has taxonomic precedence. Siphonichnus , as redefined herein, presently includes four ichnospecies. Siphonichnus eccaensis Stanistreet et al. is an unlined vertical tube characterized by concave downward laminae penetrated by a single central shaft and is interpreted to reflect downward burrowing in response to net erosion during the life span of the animal. Siphonichnus phiale (Hanken et al., 2001) is characterized by concave upwards laminae and reflects equilibrichnial behavior by the tracemaker. Siphonichnus lepusaures n. isp. is characterized by concave upwards laminae with a pair of vertically oriented, unlined tubes at the top and is interpreted as the dwelling trace of a bivalve with paired siphons responding to sediment aggradation. Siphonichnus sursumdeorsum n. isp. is characterized by concave upwards laminae in its basal third and convex upwards laminae in its upper third and is interpreted as the dwelling trace of a bivalve exhibiting equilibrichnial behavior in a dynamic depositional setting. Consolidation of these ichnotaxa into a single ichnogenus simplifies the ichnotaxonomy and provides a means of assessing the sedimentological significance of bivalve-generated dwelling/equilibrium/escape structures.
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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 | 0.000 | 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) | 0.002 | 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 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".