Molecular Phylogeny of the Lizard Clade Leiosaurae Endemic to Southern South America
Bibliographic record
Abstract
The clade Leiosaurae currently includes 18 species in the genera Diplolaemus, Leiosaurus, and Pristidactylus. It is mainly distributed in Argentina from 30° latitude south in the northwestern region of the country, to 52° south in Patagonia, from 63° longitude in coastal areas to 73° along the Andean Cordillera, across multiple habitats and including a small area in Chile. Several morphological and molecular taxonomic studies on a subset of these species have been published, but no comprehensive phylogenetic hypothesis is available for the clade. The objective of this work is to present a molecular phylogenetic hypothesis for the majority of the described species in the clade. We sequenced two mitochondrial genes, five nuclear protein coding, and three anonymous nuclear loci, and implemented traditional concatenated analyses as well as a species-tree approach. All methods inferred very similar topologies. We found the genera Diplolaemus and Leiosaurus to be monophyletic, whereas P. torquatus was retrieved as a separate lineage from the other Pristidactylus species with strong statistical support. Within Diplolaemus, D. darwinii is a very distinct lineage with an estimated divergence time of ~14.74 million yr ago (mya). Based on an early Miocene Leiosaurae fossil mandible, we estimated the crown common ancestor of the genus Leiosaurus at ~9.24 mya, and L. bellii is the earliest divergent lineage within this genus. The Argentinean Pristidactylus species seem to have radiated relatively recently (4.02 mya). A combination of geological and climatic events during Middle and Late Miocene, and climatic changes associated with glaciations, most probably played a role in the divergence of the Leiosaurae clade. The diversification patterns of Diplolaemus and Leiosaurus seem to have followed a general south-to-north direction, while the Argentinean Pristidactylus may have diversified east-to-west and north-to-south. We suggest that morphological and thermo-physiological studies combined with palaeo-niche modeling analyses are needed to test these hypotheses and better understand the biogeographical history of this clade.
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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 | 0.000 | 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 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".