Updating <i>Ceramium</i> (Rhodophyta, Ceramiales) biodiversity in the North Adriatic Sea (Mediterranean): <i>Ceramium rothianum</i> sp. nov. and rediscovery of three forgotten species
Bibliographic record
Abstract
The cosmopolitan genus Ceramium Roth (Ceramiaceae), with over 200 currently accepted species, is one of the largest in the Rhodophyta. The genus is characterized by cylindrical or slightly compressed thalli, with axial cells incompletely to completely covered by cortical cells, alternate to pseudo-dichotomous branching and straight to inrolled apices. Despite recent studies, the nomenclature and taxonomy of this genus are still very problematic, linked to the high degree of variation in morphological characters, small thallus sizes, epiphytic habit and the existence of cryptic species. The Mediterranean Sea is reported to have a particularly high diversity of Ceramium species: the North Adriatic Sea, in particular Venice and nearby coasts, was a favourite classical collecting area from where several species were described. In this study we characterize Ceramium sampled from transitional waters of the Venice Lagoon (Italy) by molecular and morphological approaches. Through phylogenetic analyses, using the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) as molecular marker, we identify six distinct taxonomic entities, of which four represent taxa not currently recognized in the Venice Lagoon or the wider Mediterranean Sea. One of these is the poorly known species Ceramium connivens Zanardini, which is non-spiny and fully corticated when mature with short naked internodes developing in older axes. Two entities with erect partially corticated thalli without spines, probably misidentified up to now as Ceramium diaphanum (Lightfoot) Roth, correspond to the new species Ceramium rothianum Wolf et al. and to the forgotten species Ceramium nodosum (Kützing) A.W. Griffiths & Harvey. The last entity, characterized by prostrate axes giving rise to narrow erect incompletely corticated, non-spiny axes, is identified as the rare, poorly known species Ceramium incospicuum Zanardini.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".