Morphology and reconstruction of the retiolitines: Silurian graptolites of the Paraplectograptus lineage (Graptolithina)
Bibliographic record
Abstract
The long ranging Silurian retiolitines belonging to the Paraplectograptus lineage (Spirograptus turriculatus to Cyrtograptus/lundgreni Biozone), represented by the genera Paraplectograptus Bouček & Münch, 1952 and Pseudoplectograptus Obut & Zaslavskaya, 1983 are described in detail based on well preserved, three-dimensional material from the Canadian Arctic and Poland. For the first time, reconstructions of their structure are attempted, and comparisons are made with the related genera, Stomatograptus Tullberg, 1883 and Retiolites Barrande, 1850. Ultrastructural details vary somewhat between the genera: the bandaging on the Paraplectograptus lineage and Pseudoplectograptus has a characteristic pustulose ornament, while that of Retiolites and Stomatograptus shows a surface of longitudinal striations. Prosicular preservation is generally incomplete, represented merely by the prosicular apex and prosicular rim. The thecal part of the Paraplectograptus and Pseudoplectograptus tubaria (rhabdosomes) possesses transverse rods, connecting rods, lateral apertural rods and lips. The ancora sleeve lists are variably developed but lack a dorsal/zigzag list, which is present in Stomatograptus and Retiolites. The Paraplectograptus lineage appears to mark an intermediate stage in the evolution of the retiolitines, from the early Silurian forms, with strong thecal and ancora sleeve frameworks (e.g. Retiolites, Stomatograptus), to late Silurian descendants with strong ancora sleeves, minimal thecal frameworks and pustular ornament, with no transverse rods.
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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 | 0.000 | 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) | 0.002 | 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".