Climatic niche evolution in the viviparous Sceloporus torquatus group (Squamata: Phrynosomatidae).
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Abstract
The cold-climate hypothesis is the main and most supported explanation of the evolution of viviparity among reptiles. This hypothesis sustains that viviparity arose as a means to save eggs from an increased mortality in nests linked with low temperatures. In this sense, some authors have stated that viviparity could constitute an evolutionary constraint. However, the link between evolutionary constraints and the evolution of ecological niches has not been well studied. Here, we study the climatic niche evolution of a group of viviparous lizards from North America to test whether the diversification of the group is linked with Phylogenetic Niche Conservatism (PNC). We evaluated phylogenetic signals and trait evolution, besides a reconstruction of ancestral climate tolerances, and did not find PNC in the ecological niche of the species in the group. Surprisingly, we did not find conservatism in any bioclimatic variables associated with temperature; we only had evidence of conservatism in Precipitation Seasonality (Bio15) and Precipitation of Coldest Quarter (Bio19). Analysis of relative disparity through time (DTT) indicates high divergence around 4.0 MYA and 0.65 MYA that coincides with orogenic and glacial periods. There is no evidence that climatic niche differentiation was the main factor in the diversification of the studied group. Orogenic and glacial periods probably promote cycles of the availability of new territories and isolation, which could promote the rapid accumulation of ecological differences between the species of the group.
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2017. Climatic niche evolution in the viviparous Sceloporus torquatus group (Squamata: Phrynosomatidae). PeerJ Preprints 5:e3493v1 https://doi.org/10.7287/peerj.preprints.3493v1note This preprint is not peer-reviewed. You may wish to reference the subsequent peer-reviewed version of this article.
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This is a submission to PeerJ for review.
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Supplemental Information
Vouchers and GenBank accession numbers for the sequences used in phylogenetic reconstruction
Model parameters estimated for Brownian Motion (BM), Ornstein-Uhlenbeck (OU), Early Burst (EB) and, Pagel’s delta (δ) for each bioclimatic variable
Ecological niche models of the species of Sceloporus torquatus group
Models are based on MAXENT using a minimum training presence threshold and a clog log output.
Phylogenetic trees showing the position of adaptive shifts under reversible-jump Bayesian method implemented in the bayou
The diameter of the circles at branches is proportional to the posterior probability of shift.
Phylogenetic Principal Component Analysis (pPCA) with two global principal components (PC1/PC2) for the weighted means of PNOs of each bioclimatic variable
The arrows are the loadings that indicate the direction and strength of each environmental variable to the overall distribution. The percentages of variance explained by the first two PCs are in the axis labels. Species names consisting of the four letters of the species epithets, except for Sceloporus ornatus caeruleos (caeru).
Additional Information
Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Norberto Martínez-Méndez conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.
Omar Mejía contributed reagents/materials/analysis tools, prepared figures and/or tables, reviewed drafts of the paper.
Jorge Ortega contributed reagents/materials/analysis tools, prepared figures and/or tables, reviewed drafts of the paper.
Fausto R. Méndez-de la Cruz contributed reagents/materials/analysis tools, prepared figures and/or tables, reviewed drafts of the paper.
Data Deposition
The following information was supplied regarding data availability:
The raw data is included in the manuscript as supplementary files.
Funding
The authors received no funding for this work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
