A review of the enigmatic microalga <i>Tetranguladinium</i> Yu et al. 1983 ex Chen et al. 1988; palaeoecology, stratigraphy and palaeogeographical distribution
Bibliographic record
Abstract
The probable zygnematacean zygospore Tetranguladinium is recorded in Mesozoic strata from southern Scandinavia for the first time. Tetranguladinium, which exhibits morphological similarities to the extant filamentous green alga Mougeotia, occurs in Jurassic–Cretaceous (J/K) boundary (latest Tithonian–Early Berriasian) assemblages from the Vomb Trough, southern Sweden and on the Danish island of Bornholm. The J/K boundary strata of southern Scandinavia were deposited in marginal marine settings, varying from freshwater marshes, lakes and flood plains, to lagoons, shoreface, and shallow marine to fully marine environments. The assemblages containing Tetranguladinium are diverse, consisting of spores and pollen, the colonial green alga Botryococcus, various other zygnematacean zygospores e.g. Ovoidites, Schizosporis and Tetraporina, and rare marine dinoflagellate cysts. A review of published fossil occurrences of Tetranguladinium reveals that its stratigraphical range extends at least from the Late Guadalupian (Mid Permian) to the Holocene. It has been recorded from Africa (Tanzania), Asia (China, Korea), Australia, northwest Europe (Denmark, Great Britain, Sweden), North America (Canada, USA), and South America (Argentina). Depositional and palaeoclimatological data for the known localities of Tetranguladinium confirm a preference for freshwater settings in a humid warm temperate to subtropical–tropical climate, often with a pronounced dry season. The palaeogeographical positions of all the known Tetranguladinium localities indicate that it is has stayed restricted within narrow belts between 30–40 south and 30–60 north of the palaeoequator since the Late Jurassic.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.005 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.003 |
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".