Phylogenetic and biogeographical history of the Afro-Madagascan genera Delonix, Colvillea and Lemuropisum (Fabaceae: Caesalpinioideae)
Bibliographic record
Abstract
Our understanding of the taxonomic limits and biogeographical evolution of the Afro-Madagascan genus Delonix and the closely related monospecific Madagascan endemic genera Colvillea and Lemuropisum have been hampered by unresolved intergeneric and interspecific relationships. Here we study the phylogenetics of the group using nucleotide sequences from ribosomal ITS, four low-copy nuclear genes and four plastid regions. We find poorly resolved gene trees typical of closely related species, but most species are resolved as monophyletic, and we report conflicting phylogenetic placements only for D. brachycarpa and C. racemosa. A time-calibrated biogeographical analysis of the concatenated matrix of all nine loci suggests that the ancestral area of the Delonix, Lemuropisum and Colvillea clade was in south-western Madagascar c. 24–18 Ma. An out-of-Madagascar dispersal to Africa took place during the Miocene, most likely by vegetative rafting. Delonix is not monophyletic due to the robustly supported placement of L. edule in Delonix, warranting treatment of Lemuropisum as congeneric with Delonix and establishment of the new name combination Delonix edule, in line with the close morphological similarities between these two genera. In contrast, the phylogenetic position of C. racemosa is unstable occurring in the Delonix–Lemuropisum clade in the nuclear gene trees, but sister to this clade in the plastid gene tree. The status of Colvillea as a distinct genus, therefore, remains questionable, but it is here maintained based on a suite of morphological distinctions, pending further insights into the relationships of this elusive genus.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".