<i>CHIHARAEA AND YAMADAIA</i> (CORALLINALES, RHODOPHYTA) REPRESENT REDUCED AND RECENTLY DERIVED ARTICULATED CORALLINE MORPHOLOGIES<sup>1</sup>
Bibliographic record
Abstract
Phycologists have hypothesized that the diminutive fronds produced by species in the genera Chiharaea and Yamadaia, which are composed of comparatively few genicula and intergenicula, represent morphological intermediates in the evolution of articulated corallines from crustose ancestors. We test this "intermediate frond hypothesis" by comparing rbcL sequences from the generitype species Chiharaea bodegensis and Yamadaia melobesioides to sequences from other coralline genera. We demonstrate that Chiharaea includes two other NE Pacific species, Arthrocardia silvae and Yamadaia americana. Chiharaea species are characterized morphologically by inflated intergenicula and axial conceptacles with apical or acentric pores. Although relationships among the three species are unresolved, Chiharaea bodegensis, C. americana comb. nov., and C. silvae comb. nov. are distinguished from one another by DNA sequences, morphology, habitat, and biogeography. Chiharaea occurs together with Alatocladia, Bossiella, Calliarthron, and Serraticardia macmillanii in a strongly supported clade of nearly endemic north Pacific articulated coralline genera and species that have evolved relatively recently compared to other articulated corallines. In contrast, NW Pacific Yamadaia melobesioides belongs in a clade with Corallina officinalis, the generitype species of Corallina, and therefore we reduce Yamadia to a synonym of Corallina and propose Corallina melobesioides comb. nov. We reject the 'intermediate frond hypothesis' and conclude that Chiharaea and Yamadaia are recently derived taxa that evolved from articulated coralline ancestors and represent a reduction in the number of genicula and intergenicula.
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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 | 0.001 | 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) | 0.001 | 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 teacher head, 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".