Paleoecology of the oldest known animal communities: Ediacaran assemblages at Mistaken Point, Newfoundland
Bibliographic record
Abstract
Ediacaran fossils at Mistaken Point, southeastern Newfoundland (terminal Neoproterozoic; 565–575 Ma) represent the oldest known animal communities. In contrast to most Phanerozoic fossil assemblages, in which postmortem transportation, bioturbation, and the accumulation of hardparts obscure community relationships, all fossils in the Mistaken Point assemblages were sessile, soft-bodied organisms that show no evidence of mobility in life or transportation after death. Mistaken Point assemblages are spectacularly preserved on large bedding planes as in situ census populations of hundreds to thousands of fossils, recording the living soft-bodied benthic community at the moment it was smothered by volcanic ash. This unique preservation style allows ecological tests routinely conducted in modern communities (e.g., species richness, abundance, “biomass,” diversity, and evenness, as well as statistical tests of nearest-neighbor interactions) to be applied to the fossil communities. Observed patterns of community variability are consistent with the theory that Mistaken Point fossil surfaces are “snapshots” recording different stages of ecological succession, progressing from communities of low-level feeders (e.g., pectinates and spindles) to frond-dominated communities with complex tiering and spatial structure. The presence of diverse slope communities at Mistaken Point suggests that the deep sea was colonized rapidly during the evolution of complex organisms. Species richness, abundance, and diversity values, as well as levels of intraspecific interaction, all fall within the typical range observed in modern slope communities. These structural similarities imply that ecological processes present in Ediacaran communities at Mistaken Point were strikingly similar to the processes that operate in modern deep-sea animal communities.
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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 | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".