Species delimitation at a global scale reveals high species richness with complex biogeography and patterns of symbiont association in <i>Peltigera</i> section <i>Peltigera</i> (lichenized Ascomycota: Lecanoromycetes)
Bibliographic record
Abstract
Abstract This comprehensive phylogenetic revision of sections Peltigera and Retifoveatae of the cyanolichen genus Peltigera is based on DNA sequences from more than 500 specimens from five continents. We amplified five loci (nrITS, β‐tubulin and three intergenic spacers part of colinear orthologous regions [COR]) for the mycobiont, and the rbcLX locus for the cyanobacterial partner Nostoc . Phylogenetic inferences (RAxML, BEAST) and species delimitation methods (bGMYC, bPTP, bPP) suggest the presence of 88 species in section Peltigera , including 50 species new to science, hence uncovering a surprisingly high proportion of previously unnoticed biodiversity. The hypervariable region in ITS1 (ITS1‐HR) is a powerful marker to identify species within sections Peltigera and Retifoveatae . Most newly delimited species are restricted to a single biogeographic region, however, up to ten species have a nearly cosmopolitan distribution. The specificity of mycobionts in their association with Nostoc cyanobionts ranges from strict specialists (associate with only one Nostoc phylogroup) to broad generalists (up to eight Nostoc phylogroups uncovered), with widespread species recruiting a broader selection of Nostoc phylogroups than species with limited distributions. In contrast, species from the P. didactyla clade characterized by small thalli and asexual vegetative propagules (soredia) associate with fewer Nostoc phylogroups (i.e., are more specialized) despite their broad distributions, and show significantly higher rates of nucleotide substitutions.
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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 | 0.000 |
| 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".