Miocene extensional tectonics explain ancient patterns of diversification among turret‐building tarantulas (Aphonopelma mojave group) in the Mojave and Sonoran deserts. (4th March 2015)

• Record Type: Journal Article
• Authors: Graham, Matthew R.; Hendrixson, Brent E.; Hamilton, Chris A.; Bond, Jason E.; McGeoch, Melodie
• Is Part Of: Journal of biogeography. Volume 42:Number 6(2015:Jun.)
• Page Start: 1052
• Page End: 1065
• Publication Date: 2015-03-04
• Subjects: Biogeography -- Periodicals; 578.09
• DOI: 10.1111/jbi.12494
• Languages: English
• ISSNs: 0305-0270

Abstract

<abstract abstract-type="main" id="jbi12494-abs-0001"> <title>Abstract</title> <sec id="jbi12494-sec-0001" sec-type="section"> <title>Aim</title> <p>Phylogeographical studies in the Mojave and Sonoran deserts often find genetic discontinuities that pre‐date the Pleistocene. A recent synthesis of phylogeographical data, called the Mojave Assembly Model, provides a hypothesis for the historical assembly of these desert biotas but does not adequately capture the complexity of pre‐Pleistocene vicariance events. We tested this model and assessed pre‐Pleistocene divergences by exploring the phylogeography of the <italic>Aphonopelma mojave</italic> group, which is composed of turret‐building tarantula species from the Mojave and Sonoran deserts.</p> </sec> <sec id="jbi12494-sec-0002" sec-type="section"> <title>Location</title> <p>Mojave and Sonoran deserts, south‐western USA.</p> </sec> <sec id="jbi12494-sec-0003" sec-type="section"> <title>Methods</title> <p>We augmented the sampling from a previous study by sequencing mitochondrial DNA (<italic>COI</italic>) from new material of the <italic>A. mojave</italic> group. We used phylogenetic and network analyses to identify clades and a molecular clock and lineages‐through‐time plots (LTT plots) to explore the timing and tempo of diversification. We tested for demographic expansion using neutrality tests and mismatch distributions. Species distribution models (SDMs) were constructed to compare current suitable habitat to that at the Last Glacial Maximum (LGM).</p> </sec> <sec id="jbi12494-sec-0004" sec-type="section"> <title>Results</title> <p>Phylogenetic, network and molecular‐clock analyses identified six major clades that probably diverged during the late Miocene. The rate of diversification appears to have slowed during the Pliocene. Most clades exhibit signals of recent demographic expansion. SDMs predicted that suitable habitat shifted south and to lower elevations during the LGM.</p> </sec> <sec id="jbi12494-sec-0005" sec-type="section"> <title>Main conclusions</title> <p>Phylogeographical analyses suggest that the <italic>A. mojave</italic> group experienced a burst of diversification in the late Miocene, followed by population expansions during the Pleistocene. Six major clades with origins in the late Miocene cannot be adequately explained by the Mojave Assembly Model. We propose the novel hypothesis that Miocene extensional tectonics caused populations to diverge in allopatry by producing low‐elevation habitat barriers. Geological models, such as kinematic reconstructions, provide an ideal but underutilized framework for testing biogeographical hypotheses in these deserts and the wider Basin and Range Province.</p> </sec> </abstract>