Biol. Rev. (2016), 91, pp. 235–254. 235 doi: 10.1111/brv.12167 Zoogeography of the San Andreas Fault system: Great Pacific Fracture Zones correspond with spatially concordant phylogeographic boundaries in western North America Andrew D. Gottscho1,2,∗ 1Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, U.S.A. 2Department of Biology, University of California, Riverside, CA 92521, U.S.A. ABSTRACT The purpose of this article is to provide an ultimate tectonic explanation for several well-studied zoogeographic boundaries along the west coast of North America, specifically, along the boundary of the North American and Pacific plates (the San Andreas Fault system). By reviewing 177 references from the plate tectonics and zoogeography literature, I demonstrate that four Great Pacific Fracture Zones (GPFZs) in the Pacific plate correspond with distributional limits and spatially concordant phylogeographic breaks for a wide variety of marine and terrestrial animals, including invertebrates, fish, amphibians, reptiles, birds, and mammals. These boundaries are: (1) Cape Mendocino and the North Coast Divide, (2) Point Conception and the Transverse Ranges, (3) Punta Eugenia and the Vizcaíno Desert, and (4) Cabo Corrientes and the Sierra Transvolcanica. However, discussion of the GPFZs is mostly absent from the zoogeography and phylogeography literature likely due to a disconnect between biologists and geologists. I argue that the four zoogeographic boundaries reviewed here ultimately originated via the same geological process (triple junction evolution). Finally, I suggest how a comparative phylogeographic approach can be used to test the hypothesis presented here. Key words: fracture zones, historical biogeography, North America, Pacific Ocean, phylogeography, plate tectonics, San Andreas Fault. CONTENTS I. Introduction .............................................................................................. 236 II. The Great Pacific Fracture Zones and the San Andreas Fault system .................................... 237 III. The Mendocino Fracture Zone, Cape Mendocino, and the North Coast Divide ......................... 241 (1) Geology and geography .............................................................................. 241 (2) Marine zoogeography ................................................................................ 242 (3) Terrestrial zoogeography ............................................................................. 243 IV. The Murray Fracture Zone, Point Conception, and the Transverse Ranges ............................. 243 (1) Geology and geography .............................................................................. 243 (2) Marine zoogeography ................................................................................ 244 (3) Terrestrial zoogeography ............................................................................. 245 V. The Molokai and Shirley Fracture Zones, Punta Eugenia, and the Vizcaíno Desert ..................... 246 (1) Geology and geography .............................................................................. 246 (2) Marine zoogeography ................................................................................ 246 (3) Terrestrial zoogeography ............................................................................. 246 * Address for correspondence (Tel: +1 619 594 3621; E-mail: [email protected]). Biological Reviews 91 (2016) 235–254 © 2014 Cambridge Philosophical Society 236 Andrew D. Gottscho VI. The Clarion Fracture Zone, Cabo Corrientes, and the Sierra Transvolcanica ........................... 247 (1) Geology and geography .............................................................................. 247 (2) Marine zoogeography ................................................................................ 248 (3) Terrestrial zoogeography ............................................................................. 248 VII. Synthesis: Biological evolution recapitulates tectonic evolution ........................................... 248 VIII. Future directions ......................................................................................... 250 IX. Conclusions .............................................................................................. 250 X. Acknowledgements ....................................................................................... 251 XI. References ................................................................................................ 251 XII. Supporting Information .................................................................................. 254 I. INTRODUCTION system, which resulted from the late Cenozoic interaction of an oceanic spreading centre with a coastal subduction zone (Atwater, 1989), remains a challenge for interpretation. ‘One of the joys of science is that, on occasion, we see a pattern that The purpose of this synthesis is to describe a broad reveals the order in what initially seems chaotic.’ zoogeographic pattern along the SAF system and to propose – Shubin (2009, p. 82) a tectonic process that might explain it, relying on published biological and geological literature. The pattern concerns The theory of plate tectonics has undoubtedly enabled four Great Pacific Fracture Zones (GPFZs) in the Pacific historical biogeographers to explain many of the ultimate plate, each of which is aligned with a major zoogeographic processes driving global biogeographic patterns (Riddle boundary or ‘break’ along the SAF system. These include (1) & Hafner, 2010; Bagley & Johnson, 2014). For example, Cape Mendocino and the North Coast Divide in northern Wallace (1876, p. 389) noted that the fauna of Celebes California, (2) Point Conception and the Transverse Ranges (Sulawesi), an oceanic Indonesian island, ‘presents the most of southern California, (3) Punta Eugenia and the Vizcaíno puzzling relations, showing affinities to Java, to the Philip- Desert of Baja California, and (4) Cabo Corrientes and pines, to the Moluccas, to New Guinea, to continental India, the Sierra Transvolcanica of central Mexico´ (Fig. 1). The and even to Africa; so that it is almost impossible to decide GPFZs are straight, parallel, and evenly spaced, implying a whether to place it in the Oriental or the Australian region.’ common mechanism for their origin. Examining this pattern Unbeknownst to Wallace, Sulawesi was sutured from several on a map immediately raises questions of ultimate causation. palaeo-islands as the Australian and Asian plates converged Why are the GPFZs aligned with dominant physiographic (R. Hall, 2002), elegantly explaining the geographically structures of western North America, which in turn concordant genetic breaks observed in anurans, primates, correspond with well-known zoogeographic boundaries? and squamate reptiles (Evans et al., 2003; McGuire et al., In some cases, the proximate mechanisms promoting 2007a). Similarly, disjunct tropical lineages that occur in the divergence across these boundaries are well understood. southern cape region of Baja California, Mexico´ posed diffi- For example, Cape Mendocino, Point Conception, and culties before the discovery of plate tectonics. It was assumed Punta Eugenia divert the dominant California Current that the tropical taxa must have dispersed to the cape from offshore, establishing upwelling jets and warmer eddies mainland Mexico,´ either overland through the northern in their leeward waters, which act as filter barriers to Colorado Desert or by rafting across the Gulf of California planktonic larvae, promoting ecological and genetic diver- (Savage, 1960). Plate tectonic models subsequently revealed gence in nearshore communities (Kelly & Palumbi, 2010; that Baja California was attached to North America Haupt, 2011). In other cases, the proximate mechanisms 5–6 million years ago (Mya) and rifted apart from the promoting divergence are hotly debated, especially for ter- continent along the San Andreas Fault (SAF) system, restrial taxa spanning the Transverse Ranges (Chatzimanolis suggesting that vicariance was also important in structuring & Caterino, 2007) and the mid-peninsular break of Baja the disjunct tropical communities of the cape region (Moore California (Leache,´ Crews & Hickerson, 2007). However, the & Buffington, 1968; Stock & Hodges, 1989; Grismer, phylogeography literature largely has not addressed the rela- 2002). Likewise, the confusing array of locally endemic tionship between the GPFZs and biogeographic boundaries slender salamanders (Batrachoseps pacificus species complex) in North America (but see Cope, 2004; Reilly & Wake, 2014). in coastal California defied interpretation until molecular Here, I attempt to fill this void by explaining how phylogenetic analyses (Jockusch, Yanev & Wake, 2001) biological evolution has recapitulated tectonic evo- combined with palinspastic reconstructions of California lution throughout the SAF system, specifically, how during the late Cenozoic (C. A. Hall, 2002) revealed the migration of the Mendocino and Rivera triple that microplate capture and strike-slip displacement junctions and the positioning of the GPFZs shaped the along the SAF explains much of the historical biogeog- distribution of zoogeographic provinces along the west coast raphy of this group (Wake, 2006). Despite the broad of North America. Due to the voluminous geological and acceptance of plate tectonics, the globally unique SAF biological literature relevant to this region, this review is not