NEW SPECIMEN OF DELTATHEROIDES CRETACICUS (METATHERIA, DELTATHEROIDA) FROM THE LATE CRETACEOUS OF MONGOLIA
Bibliographic record
Abstract
The holotype and only known maxillary dentition of Deltatheroides cretacicus, collected in 1925 from the Upper Cretaceous Djadokhta Formation of Bayn Dzak, Mongolia, has teeth that are badly damaged and worn, obscuring many details of their structure. Reported is a new specimen of D. cretacicus collected in 2000 from the Red Rum (Kholbot) locality near Ukhaa Tolgod, Mongolia that preserves four molars. Although the teeth are worn and have suffered some damage, they preserve details missing from the holotype. Comparisons with other deltatheroidans reveal that D. cretacicus is most similar to Deltatheridium pretrituberculare, known from Bayn Dzak, Ukhaa Tolgod, and the younger Barun Goyot Formation. In 1998, we published the first broadscale phylogenetic analysis of basal metatherians and relevant outgroups. That analysis is updated here with amendments taken from the new specimen of Deltatheroides cretacicus as well as from relevant literature appearing since our publication. As in 1998, the consensus trees in the updated analyses identify deltatheroidans as a basal clade of Metatheria, and Deltatheroides and Deltatheridium as more closely related to each other than to Sulestes from the Coniacian of Uzbekistan. Two isolated upper molars from the Albian–Aptian of Oklahoma and the Oldman Formation of Alberta, Atokatheridium boreni and cf. Deltatheroides sp., respectively, fall at a tetrachotomy with Deltatheroides and Deltatheridium, supporting a North American occurrence for a clade generally held to be Asiatic.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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 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".