Bibliographic record
Abstract
Petraster rigidus (Billings, 1857) (Fig. 1A) Palasterina rigidus Billings, 1857: 291. Petraster rigidus – Billings 1858: 80, pl. 10, fig. 3. — Spencer 1914: 40. — Schuchert 1915: 141, pl. 27, fig. 5. — Spencer 1927: 359. — Spencer & Wright 1966: 43. — Blake 2018: 28, pl. 4, fig. 5. Palaeaster matutina – Hall 1868: 294. TYPE MATERIAL. — Holotype. Canada • GSC 1401 a, Palasterina rigidus Billings, 1857; an incomplete, weathered specimen, only the oral surface exposed. DIAGNOSIS. — Petraster species thought to exhibit two axillaries, one triangular and reaching the lateral margin, the second embedded; a single series of robust actinals well developed, it limited to disk. TYPE LOCALITY AND HORIZON. — Cobourg beds, Ottawa, 45°026’37”N, 75°026’9”W; Trenton Limestone, Sandbianearly Katian. DESCRIPTION Petraster in which arms are moderately elongate, R reaching at least c. 20 mm. Inferomarginals robust, rectangular, relatively wide on disk, more nearly equidimensional on arm; some ossicles appear to bear accessory pustules.Two available interbrachia of the holotype differ, one with a well-defined triangular axillary and a possible second small axillary enclosed on disk adjacent to MAO. Actinals on disk in well-defined single series. Second interbrachium, ossicular arrangement poorly preserved and ill-defined. Axillary, actinals not clearly defined. Adaxials rectangular, transversely elongate. REMARKS The poorly known type species is similar to other species assigned to the genus based on overall form and the limited data available on oral-surface expression, including inferomarginal shape, disk configuration, axillary, and actinal expressions. The diagnosis focuses on expression of the better-preserved interbrachium. The skeleton aboral to inferomarginals is almost unknown, the madreporite, axials, and MAO unknown. Posited presence of two axillaries serves to separate P. rigidus from other Petraster species except from P. kinahani, with specificities of expression differing between these two. The more lateral axillary is similar to the single axillary of P. crozonensis, the adjacent inferomarginals differ in outline. A few small elongate ossicles lateral to the inferomarginals of one arm appear unlike expressions among other species, although these ossicles as preserved appear dissimilar from traces exposed on other arms.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.041 | 0.011 |
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".