Out of the desert: Paleoclimatic changes drove the diversification of arid-adapted Ocymyrmex ants in southern Africa.

Autor: Mbanyana N; Research and Exhibitions Department, South African Museum, Iziko Museums of South Africa, P.O. Box 61, Cape Town, 8000, South Africa; Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7602, South Africa. Electronic address: nnhleko@iziko.org.za., Blaimer BB; Museum für Naturkunde, Leibniz-Institute for Evolution and Biodiversity Science, Center for Integrative Biodiversity Discovery, Invalidenstr. 43, Berlin, 10115, Germany., Le Roux JJ; School of Natural Sciences, Macquarie University, Sydney, 2113, New South Wales, Australia., van Noort S; Research and Exhibitions Department, South African Museum, Iziko Museums of South Africa, P.O. Box 61, Cape Town, 8000, South Africa; Department of Biological Sciences, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa., Brady SG; Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA., Wossler TC; Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7602, South Africa.
Jazyk: angličtina
Zdroj: Molecular phylogenetics and evolution [Mol Phylogenet Evol] 2024 Feb; Vol. 191, pp. 107977. Date of Electronic Publication: 2023 Nov 24.
DOI: 10.1016/j.ympev.2023.107977
Abstrakt: A highly endemic ant fauna is found in the arid regions of southern Africa, including species in the genus Ocymyrmex. This genus of ants has higher species richness in the western arid regions of southern Africa compared to tropical and subtropical parts of the continent. The processes that have produced these patterns of diversity and distribution of arid adapted ants in southern Africa have never been investigated. The diversification of many other taxa in the region has been associated with past climate fluctuations that occurred during the Miocene epoch. In this study, the nature and timing of historical processes that may have led to the diversification within Ocymyrmex were assessed. We hypothesized that past climate oscillations, characterized by long periods of aridification, have driven the current distribution of Ocymyrmex species that resulted in the highest species richness of the genus in the Deserts & xeric shrublands biome in southern Africa. Ninety-four Ocymyrmex worker specimens from Botswana, Kenya, Namibia, South Africa, Tanzania and Zimbabwe, representing 21 currently described species and six morphospecies, were included in a phylogenomic analysis. Phylogenies for the genus, based on next generation sequencing data from ultraconserved elements, were inferred using Maximum Likelihood, and a dating analysis was performed using secondary age estimates as calibration points. A distribution database of Ocymyrmex records was used to assign species ranges, which were then coded according to major biomes in southern Africa and used as input for biogeographical analysis. We explored the phylogenomic relationships of Ocymyrmex and analysed these within a biogeographical and paleoclimatic framework to disentangle the potential processes responsible for diversification in this group. Dating analyses estimated that the crown age of Ocymyrmex dates to the Oligocene, around 32 Ma. Diversification within this group occurred between the mid-Miocene (∼12.5 Ma) and Pleistocene (∼2 Ma). Our biogeographic analyses suggest that Ocymyrmex species originated in the south-western region of southern Africa, which is now part of the Deserts & xeric shrublands biome and diversified into eastern subtropical areas during the Pliocene. Paleoclimatic changes resulting in increased aridity during the Miocene likely drove the diversification of the genus Ocymyrmex. It is most likely that the diversification of grasslands, because of historical climate change, facilitated the diversification of these ants to the eastern parts of southern Africa when open grasslands replaced forests during the early Miocene.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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