Taxonomic Review of the Genus<i>Lyonsia</i>(Pelecypoda: Lyonsiidae) from East Coast of South America, with Description of a New Species and Notes on Other Western Atlantic Species
Bibliographic record
Abstract
The genus Lyonsia Turton, 1822 is represented in the southwestern Atlantic Ocean by three species: Lyonsia hyalina (Conrad, 1831), which is very common on the east coast of the U.S.A. and has a few isolated records from Brazil and Uruguay; Lyonsia malvinensis d'Orbigny, 1846, known only from the Falkland (Malvinas) Islands; and Lyonsia alvarezii d'Orbigny, 1846, restricted to southern Brazil, Uruguay and Argentina. Some authors consider L. alvarezii a synonym of L. hyalina. Study of material deposited in malacological collections (including types) allowed a redescription of L. alvarezii and its comparison with L. hyalina. Lyonsia alvarezii is characterized by markedly inequilateral valves, with the umbo well dislocated to the anterior region. It has considerable intraspecific variation, mainly in the ventral outline, from almost straight to sinoidal, and at the umbo, from pointed to slightly rounded. The arrangement of spinules on the outer surface of the shell is irregular, usually consisting of three to five radial rows between each pair of radial lines. Previous records of L. hyalina from southern Brazil and Uruguay were based on misidentifications of shells of L. alvarezii and of Lyonsia celeste n. sp. The latter is diagnosed by its elliptical shell, with the anterior, posterior and ventral outline rounded; its subequilateral valves; and the shell spinules restricted to the umbo region of the shell surface. Four species occur on the coast of Canada and the U.S.A: L. arenosa (Møller, 1842), L. granulifera Verrill and Bush, 1898, L. hyalina and L. floridana Conrad, 1849. Three are restricted to the southwestern Atlantic: Lyonsia alvarezii has a wide distribution, from shallow waters in northeastern (∼3°S) and southeastern Brazil (∼23°S) to Argentina (∼41°S); L. malvinensis is restricted to the Falkland Islands; and Lyonsia celeste n. sp. is known only from Uruguay and Argentina.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".