Bibliographic record
Abstract
Albertosaurus and Gorgosaurus— Albertosaurus libratus is based on a nearly complete skeleton (NMC 2120) described by Lambe (1914a, b, 1917) as Gorgosaurus libratus. The holotype skull is crushed, but most of it is preserved. It hails from the Dinosaur Park Formation and is the best-sampled North American tyrannosaurid, with multiple well-preserved specimens having been collected since Lambe’s time. Albertosaurus sarcophagus Osborn, 1905 is based on a partial skeleton (NMC 5600) from the overlying Edmonton Formation of Alberta (Osborn, 1905). It is not as well preserved as the type of A. libratus. A partial skeleton with no skull from the Edmonton was later described by Parks (1928) as Albertosaurus arctunguis', most authorities now regard A. arctunguis to be a junior synonym of A. sarcophagus (Molnar et al., 1990; Carpenter, 1992). Russell (1970) was the first to synonymize Gorgosaurus with Albertosaurus. I agree with Holtz (2001a) that the character states diagnosing a more inclusive Albertosaurus are plesiomorphic (and thus problematic), and the characters used by Russell (1970) to separate them as species rely on skull and limb proportions that might be subject to preservational or ontogenetic variation. Ongoing work by Philip Currie (P. Currie, pers. comm.) is clarifying the diagnoses of these fossils, but for purposes of this analysis, they will be considered species of Albertosaurus. Carpenter (1992) argued that the promaxillary fenestra lies close to the maxillary fenestra in A. libratus, but not in A. sarcophagus, and that the promaxillary fenestra of A. libratus is invisible in lateral view. In all mature A. libratus and A. sarcophagus maxillae available for this study, the morphology of the maxillary and promaxillary fenestrae was identical. The reconstruction of A. libratus figured by Carpenter (1992:fig. 2E) looks similar to that published by Russell (1970:fig. 1), but in Russell’s reconstruction, the lateral morphological details are based on FMNH PR308. In that specimen, the promaxillary fenestra is not preserved on either side. In fact, based on the number of dentary and maxillary alveoli, this specimen may pertain to Daspletosaurus, not Albertosaurus (Carr, 1999; Holtz, 2001a)—and the promaxillary fenestra is not visible in lateral view in Daspletosaurus, as implied by Carpenter (1992) for A. libratus.
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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 | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.017 | 0.003 |
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".