Three Unusual New Species of <i>Plukenetia</i> (Euphorbiaceae) from Madagascar: Species Radiation and Convergent Evolution in <i>P</i>. sect. <i>Madagascarienses</i>
Bibliographic record
Abstract
Abstract— We describe three unusual new species of Plukenetia sect. Madagascarienses from eastern Madagascar based on morphology, pollen, and molecular data. Plukenetia analameranensis is unusual in the genus and section for its flat androecium of sessile anthers on a flat receptacle and is most similar to P. ankaranensis sharing obovoid stylar columns. Plukenetia antilahimenae and P. randrianaivoi are distinct in sect. Madagascarienses and among palaeotropical species for their elliptic or obovate-elliptic, pinnately veined leaf blades. They differ primarily in indumentum characters, including stems and inflorescence axes pubescent versus glabrous, and stipule size. Pollen of the new species (unknown in P. randrianaivoi) have reticulate or finely reticulate exines, while that of P. ankaranensis has a rugulate exine; this pollen morphology contrasts with that of all other palaeotropical species, which have foveolate exines. Phylogenetic analysis of nuclear ribosomal ETS and ITS data show that P. randrianaivoi is firmly embedded in the sect. Madagascarienses clade and sister to P. ankaranensis (the other two new species could not be sequenced). Based on these molecular and pollen results, together with floral characters (most importantly completely connate styles), we suggest that the three new species and P. ankaranensis form a subclade, sister to the other two Malagasy species, P. decidua and P. madagascariensis. With the description of these three new species, sect. Madagascarienses (6 spp.) becomes substantially more diverse morphologically. This species radiation in Madagascar resulted in the independent evolution of several leaf and pollen characters that previously were thought to distinguish the two major clades of Plukenetia, specifically pinnately veined leaf blades and reticulate pollen that look remarkably similar to the leaves and pollen of the neotropical pinnately veined clade. An emended description of section Madagascarienses, a key to the species of sect. Madagascarienses, and an updated key to the sections of Plukenetia are provided.
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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 | 0.001 |
| 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".