Revisiting the identification of Syllipsimopodi bideni and timing of the decabrachian-octobrachian divergence
Bibliographic record
Abstract
Recently, on the basis of a single specimen (ROMIP 64897) from the Royal Ontario Museum (Canada), Whalen and Landman 1 described the new coleoid taxon with a fairly completely preserved frontal part as Syllipsimopodi bideni . The specimen, recovered from the Bear Gulch Limestone, Heath Formation in Fergus County, Montana, USA, is of Serpukhovian age 2 . Based on the suggested presence of a gladius, ten arms, and fins, as well as the supposed absence of a phragmocone, the authors interpreted the “remarkably well-preserved” specimen as “the oldest definitive vampyropod and crown coleoid” 1 . We herein test if the fidelity of preserved characters in S. bideni affects the interpretation of this organism—particularly by comparing these characters to other soft bodied cephalopod fossils from Bear Gulch. We provide evidence for the likely synonymy of S. bideni and Gordoniconus beargulchensis . Our interpretation casts doubt on the phylogeny proposed by Whalen and Landman 1 , who suggested S. bideni as the oldest vamyropod. Vampyropoda ( = Octobrachia or Octopodiformes) is considered to be the sister group of all ten-armed cephalopods (Decabrachia) 3 , 4 , 5 , which is also supported by recent molecular analyses 6 , 7 , 8 .
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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 | 0.001 | 0.001 |
| 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 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".