A new derived mosasaurine (Squamata: Mosasaurinae) from south-western Japan reveals unexpected postcranial diversity among hydropedal mosasaurs
Bibliographic record
Abstract
Reported herein is a largely complete mosasaurine mosasaur (Squamata: Mosasauridae) skeleton from Wakayama Prefecture, south-western Japan. It is represented by many skeletal elements including the skull, a complete cervical and dorsal vertebral series with more than 40 vertebrae, paired ribs, right and left front flippers, and the left hind flipper. The specimen is from near the Campanian/Maastrichtian boundary (c. 72 Ma) within the Hasegawa Muddy Sandstone Member of the Toyajo Formation. We assign the specimen (WMNH-Ge-1140240002) to a new genus and species based on a unique combination of characters including: jaw bones gracile; premaxilla–maxilla suture terminating above or just posterior to fourth maxillary tooth; frontal median dorsal ridge robust; frontal alae broadly rounded; frontal descending processes extending parallel to each other; jugal process of postorbitofrontal extending laterally, constituting dorsal half of posterior orbital margin; anterior and posterior carinae on marginal teeth pinched out in cross-section; cervical centra compressed dorsoventrally; zygosphenes and zygantra present at least to the 19th (= posterior) dorsal vertebrae; neural spine orientation changing from procumbent to recumbent along posterior dorsal vertebrae; front and hind flippers longer than mandible; hind flipper longer than front flipper; and hyperphalangy of up to nine. The two sets of large, wing-shaped flippers were likely selected for fast manoeuvring, as seen in the humpback whale among extant mysticetes. The presence of a dorsal fin is suggested by the sweeping arrangement of the neural spines along the dorsal vertebrae, well posterior to the presumed centre of gravity. Finally, the pubis and the ilium articulate at an obtuse angle in anteroposterior view, allowing no bony contact between the latter and the axial skeleton.http://zoobank.org/urn:lsid:zoobank.org:pub:E36B7A31-BFCA-47B8-9E97-AB249AC9D79B
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 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".