Organic-walled microphytoplankton assemblage of the Middle Devonian (Givetian) Arkona, Hungry Hollow and Widder formations, Ontario, Canada: biostratigraphic and palaeogeographic significance
Bibliographic record
Abstract
A diverse and abundant organic-walled microphytoplankton assemblage, consisting of 49 species of acritarchs, prasinophyte phycomata and chitinozoans, was recovered from a 13.3 m-section of the Middle Devonian (Givetian) Arkona, Hungry Hollow and Widder formations at Hungry Hollow, Ontario, Canada. Close similarity exists between this assemblage and others described previously from the Givetian of North America. Marine palynofloras of comparable age from elsewhere in North America share between 59–96% of the species identified in the present assemblage, thus testifying to its stratigraphic-correlative applicability in a regional context. Species widely occurring in North America and typically Givetian (although not restricted therein) include: Arkonites bilixus, Cymatiosphaera canadense, Diexallophasis simplex, Duvernaysphaera angelae, D. tenuicingulata, Estiastra rhytidoa, Exochoderma arca, Gorgonisphaeridium inflatum, Hapsidopalla chela, Leiofusa pyrena, Muraticavea munifica, Oppilatala sparsa, Palacanthus ledanoisii, Polyedryxium ambitum, Staplinium cuboides, Tyligmasoma alargada, Uncinisphaera acantha, Veryhachium pastoris, Villosacapsula compta and V. rosendae. Palaeogeographically, Middle Devonian organic-walled microphytoplankton taxa display a conspicuous degree of cosmopolitanism, with many species shared with Laurasia (Laurentia, Avalonia, Baltica), Gondwana (principally Argentina, Ghana, Libya, Algerian Sahara, Western Australia) and Kazakhstan (northwestern China).
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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 | 0.000 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".