A New Irvingtonian Water Shrew (Insectivora: Soricidae) from Nuckolls County, Nebraska: Systematics, Functional Morphology and Paleoecology
Bibliographic record
Abstract
Eight species of three genera of shrews were recovered from the Albert Ahrens Site, Nuckolls County, Nebraska. Based on dental morphology, biomechanics, and paleoecology, one of these is believed to represent a previously undescribed species of water shrew. It closely resembles the modern North American water shrews, Sorex palustris and Sorex bendirii, in overall morphology but differs from both by having a taller coronoid, more anteroposteriorly compressed unicuspids, less constricted snout, and a bite force index (BFI) that falls between S. palustris and S. bendirii. Twelve of 33 quantitative characters significantly distinguish S. sp. A as a new species. The BFI and I1 morphology, in addition to fish remains and an area of Sorex sympatry in central Canada, suggest a similar paleoecology of cool, moist boreal parkland habitat. The Albert Ahrens Site is important geologically and paleontologically because it lies stratigraphically higher than a nearby mid-Pleistocene ash bed and its fauna is similar to the Cudahy local fauna (I. f.), Meade County, Kansas. Ash clasts within the highly fossiliferous bone pebble matrix have been found to match exactly the nearby ash bed. Radiometric dating and mineralogic examination of samples of this ash reveals that the source is the 0.6 Ma Lava Creek B Ash, making the fossil site younger than the Cudahy l. f. This temporal relationship to the Cudahy I. f. is important to understanding the evolutionary development and paleoecology of certain long-tailed shrews (genus Sorex) in the Midwest.
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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".