Bivalved arthropods from the Middle Ordovician Winneshiek Lagerstätte, Iowa, USA
Bibliographic record
Abstract
Abstract The Middle Ordovician (Darriwilian) Winneshiek Lagerstätte of northeast Iowa is preserved in a meteorite crater. Besides conodonts, the fossils are dominated by arthropods, particularly eurypterids and phyllocarids. Here we describe the bivalved forms, which include at least seven different taxa. The small phyllocaridCeratiocaris winneshiekensis, new species, is the most abundant; it is the oldest representative of the Ceratiocarididae. A single incomplete abdomen and telson bearing furcal rami is reminiscent of notostracan branchiopods but its affinities are unknown.Decoracaris hildebrandi, new genus and species, is a rare form with a shield that extends anteriorly into a swollen horn and reaches lengths of 9 cm: it may represent a thylacocephalan crustacean but this cannot be confirmed without soft parts.Iosuperstes collisionis, new genus and species, is represented by suboval valves 10–25 mm long: its affinities are unknown. A probable leperditicopid, which ranges in length from 8 to 18 mm, is commonly preserved in a ‘butterflied’ configuration. It does not preserve the scars and sinuses characteristic of three-dimensionally preserved leperditicopids from elsewhere. Finally the fauna includes at least three ostracods, including a palaeocope with a granular surface and relief similar toLomatopisthia, and a smooth ?podocope. The Winneshiek fauna differs from those of other Ordovician Lagerstätten from restricted settings such as Airport Cove and William Lake in Manitoba (Katian) where, apart from ostracods, bivalved arthropods are absent, and Silurian examples such as Brandon Bridge (Telychian), which lacks eurypterids, and the Williamsville Member of the Bertie Formation (Pridoli) where conodont assemblages are absent.
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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".