A 425-Million-Year-Old Silurian Pentastomid Parasitic on Ostracods
Bibliographic record
Abstract
Pentastomids (tongue worms) are worm-like arthropods known today from ∼140 species [1Christoffersen M.L. De Assis J.E. A systematic monograph of the Recent Pentastomida, with a compilation of their hosts.Zool. Meded. 2013; 87: 1-206Google Scholar]. All but four are parasitic on vertebrates. Their life cycle typically involves larval development in an intermediate host followed by maturation in the respiratory tract of a definitive terrestrial host. Fossil pentastomids are exceedingly rare and are known only from isolated juveniles [2Castellani C. Maas A. Waloszek D. Haug J.T. New pentastomids from the Late Cambrian of Sweden - deeper insight of the ontogeny of fossil tongue worms.Palaeontographica Abt. A. 2011; 293: 95-145Google Scholar, 3Andres D. Phosphatisierte Fossilien aus dem Unteren Ordoviz vin Südschweden.Berl. Geowissenschaftliche Abh. 1989; 6: 9-19Google Scholar, 4Walossek D. Muller K.J. Pentastomid parasites from the Lower Palaeozoic of Sweden.Trans. R. Soc. Edinb. Earth Sci. 1994; 85: 1-37Crossref Scopus (71) Google Scholar, 5Walossek D. Repetski J.E. Muller K.J. An exceptionally preserved parasitic arthropod, Heymonsicambria taylori n. sp. (Arthropoda incertae sedis: Pentastomida), from Cambrian-Ordovician boundary beds of Newfoundland.Can. J. Earth Sci. 1994; 31: 1664-1671Crossref Scopus (32) Google Scholar, 6Waloszek D. Repetski J.E. Maas A. A new Late Cambrian pentastomid and a review of the relationships of this parasitic group.Trans. R. Soc. Edinb. Earth Sci. 2006; 96: 163-176Crossref Google Scholar]. The identity of the possible hosts of fossil pentastomids and the origin of their lifestyle have generated much debate. A new, exceptionally preserved species, described based on adults from 425-million-year-old marine rocks, is the only known fossil pentastomid associated with a host, in this case a species of ostracod crustacean. The pentastomids are preserved near eggs within the ostracod and also, uniquely for any fossil or living pentastomid, are attached externally to the host. This discovery affirms the origin of pentastomids as ectoparasitic on marine invertebrates. The terrestrialization of pentastomids may have occurred in parallel with the vertebrate invasion of land.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.002 | 0.013 |
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; both teacher heads agree on what is shown here.
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".