PALEOECOLOGIC AND TAXONOMIC IMPLICATIONS OF SPHENOTHALLUS AND SPHENOTHALLUS-LIKE SPECIMENS FROM OHIO AND AREAS ADJACENT TO OHIO
Bibliographic record
Abstract
Abstract Sphenothallus and fossils similar to Sphenothallus are found in Ordovician, Devonian, and Mississippian rock units in Ohio and adjacent states and provinces. Although the Ordovician of Québec, Ontario, and Indiana has yielded parts of tubes, Ordovician specimens from southwest Ohio and nearby areas consist almost entirely of holdfasts on hardgrounds and shelly fossils. Sphenothallus is abundant in the Chagrin Shale (Famennian) of northeast Ohio where it is found in about four percent of concretions that contain identifiable fossils. The Chagrin specimens, usually parts of tubes, are occasionally preserved three-dimensionally. The rate of distal expansion of Chagrin Sphenothallus tubes varies intraspecifically; thus, this rate cannot be used to distinguish species. Some Chagrin specimens are attached to larger, conspecific specimens and to articulate brachiopods. Brachiopods have also been found attached to Chagrin Sphenothallus. Bedford-Berea sequence (Famennian) specimens from northern Kentucky and Meadville Member (Kinderhookian or Osagian) specimens from the Cuyahoga Formation of northeast Ohio are usually preserved as flattened tubes. In both occurrences tubes are similar in width, indicating that individuals in each assemblage are probably the same age. Meadville tubes possess characteristics diagnostic of Sphenothallus, but Bedford-Berea specimens, which lack longitudinal thickenings and exhibit little tube tapering, cannot be assigned to Sphenothallus sensu strictu. Sphenothallus was a gregarious, opportunistic species, tolerant of dysaerobic conditions and able to colonize environments ranging from hardgrounds to soft, muddy sea bottoms. No distinct branching was observed among the Chagrin, Bedford-Berea, or Meadville specimens, suggesting that larval dispersal was the primary mode of reproduction for the genus.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 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".