<i>Drumhellera kurmanniae</i> Serbet and Stockey: Reconstructing a Sequoioid Conifer (Cupressaceae) from the Late Cretaceous (Campanian–Maastrichtian) of Western Canada
Bibliographic record
Abstract
Premise of research. Late Cretaceous fossil floras from the badlands around Drumheller, Alberta, Canada, are represented by both permineralized and compressed specimens at multiple stratigraphic levels. Thousands of specimens for several species of conifer plants have been isolated from the assemblages, thus facilitating the development of organismal concepts for such species. Stems, leafy shoots, pollen cones borne on shoots, seed cones, and seeds provide the basis for developing an organismal concept for the sequoioid species Drumhellera kurmanniae Serbet and Stockey. Methodology. Permineralized specimens were extracted from ironstone nodules, photographed, and sectioned using the cellulose acetate peel technique. Compressed specimens were photographed with reflected light. Pivotal results. The concept of D. kurmanniae is expanded to include vegetative shoots and seed cones, as well as pollen cones with subtending shoots, to characterize a species of Late Cretaceous sequoioid conifer plants. An evaluation of the structural features of D. kurmanniae emphasizes that taxonomic characters of extinct sequoioid conifers are both extremely cryptic and variable within the same species and that there is a wide range of overlap for individual characters of different species. Conclusions. Drumhellera kurmanniae has characteristic features of the family Cupressaceae, subfamily Sequoioideae, but also displays a diagnostic suite of characters not found in similar extinct and extant genera. Evaluation of taxonomically informative characters confirms that large collections of multiorgan fossils from the same material source are required to clearly identify and differentiate among species of the Sequoioideae. This realization calls to question the identification of many Late Cretaceous fossils that have been identified from only a small number of specimens from each material source. The abundance of specimens that represent D. kurmanniae and several other conifers in the Drumheller assemblages clarifies the nature of mixed conifer forest canopies during the Campanian and Maastrichtian of Alberta, Canada, thus enhancing our understanding of plant community complexity in Late Cretaceous landscapes of western North America.
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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".