Cranial anatomy and systematics of <i>Dendrerpeton</i> cf. <i>helogenes</i> (Tetrapoda, Temnospondyli) from the Pennsylvanian of Joggins, revisited through micro‐CT scanning
Bibliographic record
Abstract
Abstract The Joggins Fossil Cliffs constitute an upper Carboniferous (Pennsylvanian) locality in Nova Scotia (Canada). This site, known for the rich record of fossils preserved in the palaeoenvironment in which they lived, sheds light on the late Carboniferous environment. More specifically, Joggins records one of the earliest Pennsylvanian ecosystems and is unique in preserving a rich diversity of terrestrial fauna compared with other Pennsylvanian communities, which mostly preserve aquatic fauna. For vertebrate palaeontology, the significance of Joggins lies in the discovery of the earliest amniotes (Hylonomus lyelli Dawson, Protoclepsydrops haplous Carroll, and Asaphestera platyris (Steen)) and the second earliest temnospondyl, Dendrerpeton (only Balanerpeton woodi Milner & Sequeira occurs earlier). Computed tomography of the most complete tetrapod specimen found at Joggins, the temnospondyl amphibian currently referred to Dendrysekos helogenes Steen, made accessible the internal anatomy and revealed previously obscured anatomical structures, including the stapes, scleral plates, and partial sphenethmoid. These newly accessible features enabled a redescription of this specimen. The resulting anatomical comparisons and phylogenetic analyses suggest that the genus Dendrysekos is a junior synonym of Dendrerpeton; the diagnostic characters previously distinguishing the two genera are considered to be instead a combination of ontogenetic and preservational parameters, and the two genera were not resolved as discrete. Additionally, the phylogenetic analyses show that the interrelationships between the main early temnospondyl groups (Edopoidea, Dvinosauria, Eryopoidea and Dissorophoidea) are neither robust nor well supported, due to the low number of shared derived characters.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.003 | 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".