An unexpected fossil lagerstätte under the Early Triassic hyperthermal event showing a modern-type marine ecosystem
Bibliographic record
Abstract
Following the most severe mass extinction event during the Phanerozoic, the Permian-Triassic mass extinction (PTME, ~251.9 Ma), Early Triassic marine fossil communities were thought to be depauperate, poorly diversified, and dominated by abundant and cosmopolitan disaster or opportunistic taxa. Full re-establishment of complex marine ecosystems was thought to have not occurred until, ~8 million years after the PTME, being represented by the Luoping Biota. The highly suppressed Early Triassic marine ecosystem has been thought to be a consequence of recurrent environmental stresses, including high sea surface temperature, episodes of oceanic acidification, and anoxic/euxinic events mainly occurring during the Permian-Triassic transition, the late Dienerian and late Smithian. Alternatively, it can also result from preservation and sampling biases, which are often neglected in many previous works. Here, we report an exceptionally preserved Early Triassic fossil assemblage, the Guiyang Biota, from the Daye Formation near Guiyang, South China. The Guiyang Biota comprises at least 12 classes and 19 orders, including diverse fish fauna and malacostracans, revealing a trophically-complex marine ecosystem. High-precision U-Pb dating shows that the age of the Guiyang Biota is 250.83 +0.07/-0.06 million years ago. This is only 1.08 ± 0.08 million years after the severe Permian-Triassic mass extinction, and this assemblage therefore represents the oldest known Mesozoic lagerstätte so far. The Guiyang Biota indicates the rapid rise of modern-type marine ecosystems after the Permian-Triassic mass extinction.
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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".