COPROLITES IN THE RAVENS THROAT RIVER LAGERSTÄTTE OF NORTHWESTERN CANADA: IMPLICATIONS FOR THE MIDDLE CAMBRIAN FOOD WEB
Bibliographic record
Abstract
ABSTRACT The Rockslide Formation (middle Cambrian, Drumian, Bolaspidella Zone) of the Mackenzie Mountains, northwestern Canada, hosts the Ravens Throat River Lagerstätte, which consists of two, 1-m thick intervals of greenish, thinly laminated, locally burrowed, slightly calcareous mudstone yielding a low-diversity and low-abundance fauna of bivalved arthropods, ‘worms', hyoliths, and trilobites. Also present are flattened, circular, black carbonaceous objects averaging 15 mm in diameter, interpreted as coprolites preserved in either dorsal or ventral view. Many consist of aggregates of ovate carbonaceous flakes 0.5–2 mm long, which are probably compacted fecal pellets. Two-thirds contain a variably disarticulated pair of arthropod valves, and many also contain coiled to fragmented, corrugated ‘worm' cuticle, either alone or together with valves. A few contain an enrolled agnostoid. In rare cases a ptychoparioid cranidium, agnostoid shield, bradoriid valve, or hyolith conch or operculum is present; these are taken to be due to capture and ingestion of bioclasts from the adjacent seafloor. Many of the coprolites are associated with semi-circular spreiten produced by movement of the worm-like predator while it occupied a vertical burrow. Its identity is unknown but it clearly exhibited prey selectivity. Many coprolites contain one or more articulated hyoliths, ptychoparioid trilobites, or outstretched agnostoid arthropods oriented dorsal side up. These are interpreted as opportunistic coprovores drawn to the organic-rich fecal mass while it was lodged near the entrance to the burrow. This argues that hyoliths were mobile detritivores, and agnostoids were mainly nektobenthic or benthic, like the ptychoparioid trilobites. Fecal matter was probably an important source of nutrition in the Cambrian food web.
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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) | 0.000 | 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".