Cyclocystoids (Echinodermata) from the Upper Ordovician (early Katian) Kirkfield and Verulam formations of Ontario, Canada: implications for cyclocystoid skeletal homologies, anatomy, functional morphology, life mode, and systematics
Bibliographic record
Abstract
Abstract New discoveries prompt reinterpretations of one of the most enigmatic echinoderm classes, the Cyclocystoidea. Exceptionally well-preserved cyclocystoids have been discovered in the Upper Ordovician (Katian) Kirkfield and Verulam formations in the Lake Simcoe region of southern Ontario, Canada. Four different cyclocystoid taxa are present, including Cyclocystoides cf. C. scammaphoris , Nicholsodiscus cf. N. anticostiensis , Zygocycloides marstoni , and Brechincycloides stanhynei new genus new species. These specimens reveal that the central disk of cyclocystoids consists largely of perforate extraxial plates and that the ever-present sutural pores are epispires surrounded by annular plates that may or may not be in lateral contact with each other. The specimens of B. stanhynei n. gen. n. sp. are significant because they are the first cyclocystoid fossils to reveal that the hydropore/gonopore and periproct are positioned on the aboral side of the central disk. The suggestively complex marginal ring, previously of undetermined origin, represents articulated floor plates in a circular arrangement supporting a circumferential water vascular system. Furthermore, the marginal ring reveals growth zones that correspond to axes of pentaradial symmetry. In the new interpretation, cupules are tube foot basins, and channels through the marginal ossicles can be explained best in the context of the axial origin as floor plates accompanied by a cover plate system. Application of the Extraxial–Axial Theory (EAT) compels a revised understanding of key anatomies comparable with other early radial echinoderms. We document evidence for cyclocystoid orientation in life with epispires facing upward and the tube foot basins in the floor plates directed towards the substrate. The new family Brechincycloididae is proposed for all cyclocystoids whose apomorphy consists of a flat, attenuated shelf tapering away from the proximal side of each floor plate. UUID: http://zoobank.org/605fdf27-b38b-4d41-824b-d10b139f90f5
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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 | 0.000 | 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 | 0.000 |
| 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".