Phylogeny of the Echinoderes coulli-group (Kinorhyncha : Cyclorhagida : Echinoderidae) – a cosmopolitan species group trapped in the intertidal
Bibliographic record
Abstract
Kinorhyncha is a phylum of microscopic, benthic marine invertebrates found throughout the world, from the Arctic to Antarctica and from the intertidal zone to the deep sea. Within the most species-rich genus, Echinoderes, we find a putatively monophyletic species group, the so-called Echinoderes coulli-group. The remarkable morphological similarities of the E. coulli-group species and the fact that the group has a global distribution even though most of the species are restricted to intertidal habitats, has led to the hypothesis that dispersal and speciation within the group has been driven by the process of continental drift. However, this has never been confirmed empirically. With morphology and two molecular loci, COI and 18S, we calculated phylogenetic trees by analysing datasets separately and in combination using Maximum Parsimony, Maximum Likelihood and Bayesian Inference. Using different models of evolution in combination with different statistical approaches, we show that two major clade divergences were consistent with historic drifting of continents, suggesting that vicariance has played an important role for the speciation within the E. coulli-group. Furthermore, we found that reconstructions of past tectonic drifting since the Devonian (416–359 million years ago) were able to explain present species distributions, and suggest that the group originated in a supposedly vast shallow marine environment in north-eastern Gondwana by the mid-late Silurian, 426–416 million years ago.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.001 | 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".