TY - JOUR
T1 - Remarkably rapid, recent diversification of Cochemiea and Mammillaria in the Baja California, Mexico region
AU - Breslin, Peter B.
AU - Wojciechowski, Martin F.
AU - Majure, Lucas C.
N1 - Funding Information:
The lead author would like to acknowledge the Arizona State University College of Liberal Arts and Sciences, The Cactus and Succulent Society of America, The San Diego Cactus and Succulent Society, The Central Arizona Cactus and Succulent Society, and more than 70 individual donors to a crowd-funding effort at website www.experiment.com for funding. The authors thank the reviewers for their helpful and valuable comments and suggestions.
Publisher Copyright:
© 2022 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.
PY - 2022/9
Y1 - 2022/9
N2 - Premise: The Cactaceae of northwestern Mexico and the southwestern United States constitute a major component of the angiosperm biodiversity of the region. The Mammilloid clade, (Cactaceae, tribe Cacteae), composed of the genera Cochemiea, Coryphantha, Cumarinia, Mammillaria, and Pelecyphora is especially species rich. We sought to understand the timing, geographical and climate influences correlated with expansion of the Mammilloid clade, through the Sonoran Desert into Baja California. Methods: We reconstructed the historical biogeography of the Mammilloid clade, using Bayesian and maximum likelihood methods, based on a strongly supported molecular phylogeny. We also estimated divergence times, the timing of emergence of key characters, and diversification rates and rate shifts of the Mammilloid clade. Results: We found that the most recent common ancestor of Cochemiea arrived in the Cape region of Baja California from the Sonoran Desert region approximately 5 million years ago, coinciding with the timing of peninsular rifting from the mainland, suggesting dispersal and vicariance as causes of species richness and endemism. The diversification rate for Cochemiea is estimated to be approximately 12 times that of the mean background diversification rate for angiosperms. Divergence time estimation shows that many of the extant taxa in Cochemiea and Baja California Mammillaria emerged from common ancestors 1 million to 200,000 years ago, having a mid-Pleistocene origin. Conclusions: Cochemiea and Mammillaria of the Baja California region are examples of recent, rapid diversification. Geological and climatic forces at multiple spatial and temporal scales are correlated with the western distributions of the Mammilloid clade.
AB - Premise: The Cactaceae of northwestern Mexico and the southwestern United States constitute a major component of the angiosperm biodiversity of the region. The Mammilloid clade, (Cactaceae, tribe Cacteae), composed of the genera Cochemiea, Coryphantha, Cumarinia, Mammillaria, and Pelecyphora is especially species rich. We sought to understand the timing, geographical and climate influences correlated with expansion of the Mammilloid clade, through the Sonoran Desert into Baja California. Methods: We reconstructed the historical biogeography of the Mammilloid clade, using Bayesian and maximum likelihood methods, based on a strongly supported molecular phylogeny. We also estimated divergence times, the timing of emergence of key characters, and diversification rates and rate shifts of the Mammilloid clade. Results: We found that the most recent common ancestor of Cochemiea arrived in the Cape region of Baja California from the Sonoran Desert region approximately 5 million years ago, coinciding with the timing of peninsular rifting from the mainland, suggesting dispersal and vicariance as causes of species richness and endemism. The diversification rate for Cochemiea is estimated to be approximately 12 times that of the mean background diversification rate for angiosperms. Divergence time estimation shows that many of the extant taxa in Cochemiea and Baja California Mammillaria emerged from common ancestors 1 million to 200,000 years ago, having a mid-Pleistocene origin. Conclusions: Cochemiea and Mammillaria of the Baja California region are examples of recent, rapid diversification. Geological and climatic forces at multiple spatial and temporal scales are correlated with the western distributions of the Mammilloid clade.
KW - Baja California
KW - Cactaceae
KW - Mammilloid clade
KW - Sonoran Desert
KW - ancestral state reconstruction
KW - biogeography
KW - endemism
KW - evolution
KW - rapid diversification
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U2 - 10.1002/ajb2.16048
DO - 10.1002/ajb2.16048
M3 - Article
C2 - 35979551
AN - SCOPUS:85137606161
SN - 0002-9122
VL - 109
SP - 1472
EP - 1487
JO - American Journal of Botany
JF - American Journal of Botany
IS - 9
ER -