A New Conulariid (Cnidaria, Scyphozoa) From the Terminal Ediacaran of Brazil
Bibliographic record
Abstract
Paraconularia ediacaran. sp., the oldest documented conulariid cnidarian, is described based on a compressed thin specimen from the terminal Ediacaran Tamengo Formation near Corumbá, Mato Grosso do Sul State, Brazil. The conulariid was collected from a laminated silty shale bed also containingCorumbella werneriand vendotaenid algae. The specimen consists of four partial faces, two of which are mostly covered, and one exposed corner sulcus. The two exposed faces exhibit 32 bell-curve-shaped, nodose transverse ribs, with some nodes preserving a short, adaperturally directed interspace ridge (spine). The transverse ribs bend adapertureward on the shoulders of the corner sulcus, within which the ribs terminate, with the end portions of the ribs from one face alternating with and slightly overlapping those from the adjoining face. This is the first Ediacaran body fossil showing compelling evidence of homology with a particular conulariid genus. However, unlike the periderm of Phanerozoic conulariids, the periderm ofP.ediacaralacks calcium phosphate, a difference which may be original or an artifact of diagenesis or weathering. The discovery ofP.ediacarain the Tamengo Formation corroborates the hypothesis, based in part on molecular clock studies, that cnidarians originated during mid-late Proterozoic times, and serves as a new internal calibration point, dating the split between scyphozoan and cubozoan cnidarians at no later than 542 Ma. Furthermore,P. ediacarareinforces the argument that the final phase of Ediacaran biotic evolution featured the advent of large-bodied eumetazoans, including, possibly, predators.
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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) | 0.001 | 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 | 0.001 | 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".