Primer registro de Xiphactinus Leidy, 1870 (Teleostei, Ichthyodectiformes) en el Cretácico Superior de América del Sur (Formación La Luna, Venezuela)
Bibliographic record
Abstract
This paper describes the fossil remains of an Ichthyodectiform fish collected in the Cenomanian limestones belonging to La Aguada Member, La Luna Formation, near Monay, Candelaria Municipality, Trujillo State, western Venezuela.This fossil consists of fragments of the nasal region of the skull, both jaws, and four vertebrae of the same individual.Despite the fragmentary condition of this fossil, its preserved characteristics show that it is a representative of the genus Xiphactinus Leidy.These characters are the occurrence of conic, caniniform teeth of irregular size set within deep alveolar cavities forming a single row in the maxilla, premaxilla, and dentary bones; hypertrophied premaxilla teeth; and a wide maxilla-premaxilla articulation that involves the entire height of both bones.Unfortunately, there are not enough characters preserved to determinate the specific identity of this fossil; nevertheless, this finding of Xiphactinus in a South American locality represents the first report of this genus from the marine domains of the Mesozoic Gondwana.This report extends the paleobiogeographic distribution of Xiphactinus that is well known through previous findings in Cretaceous (Albian-Maastrichthian) marine localities, within the Inland Sea of North America and the northern border of the Tethys Sea in Europe.
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 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 | 0.000 |
| 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 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".