Morphology and phylogeny of some early Silurian (Mid-Rhuddanian) monograptid graptolites from the South Urals of Russia
Bibliographic record
Abstract
An unusually well-preserved fauna of isolated monograptid graptolites has been recovered from the Sakmara Formation, in the Orenburg District of the South Urals of Russia. Seven different taxa belonging to three genera can be distinguished in these collections, including four new species, Pribylograptus orskensis n. sp., Monoclimacis ? galeritus n. sp., Monoclimacis ? orenburgensis n. sp., and Monoclimacis ? oscitatus n. sp. Study of these new species using infrared video microscopy reveals two features never previously identified in monograptid graptolites on the three species of Monoclimacis ?: thecal hoods constructed from both apertural and genicular fuselli; and, a resorption porus that shows some outward inflation or bulging as well as slight fusellar deflection. These two features may both represent stages of morphologic transition to the more “advanced” primary porus and apertural hoods and hooks seen in later monograptids. Phylogenetic analysis of these and some other Rhuddanian taxa suggests that species with “monoclimacid”” thecae arose once in the Rhuddanian from a Huttagraptus ancestor and these species later gave rise to the various groups of biform and uniform monograptids with apertural-hooded and hooked thecae. Those biform taxa with “monoclimacid” or hooked proximal thecae and lappeted (“pribylograptid”) distal thecae appear to have arisen from within this group independently of the lineage leading to Pribylograptus sensu stricto.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".