PMC

Panel (a). Upper panel: maps of the Baja peninsula and continental Sonora showing sampled Washingotnia populations. Each of the maps represents one hypothetical divergence scenario tested within AMOVA. The a priori defined regions are separated by three hypothesized phylogeographical breaks, including: (1) current taxonomy, (2) three major geographic regions and (3) each sierra as unique genetic entity. Arrows indicate species or sierras as follows: SL, Sierra Laguna; SM, Sierra Mechudo; SG, Sierra la Giganta; SSP, Sierra San Pedro; SLI + SSF, combined Sierra Libertad and Sierra San Francisco; Cat, Cataviña; SJ, Sierra Juarez; and Son, Sierra Aguaje. Lower left panel: results of analysis of molecular variance (AMOVA) comparison of three vicariance scenarios, based on nuclear and plastid markers. Lower right panel: picture of one of the sampling sites of W. robusta in Sierra Mechudo (SM). Panel (b). Upper panel: maps of the Baja peninsula and Guadalupe Island showing sampled Brahea populations. Each of the maps represents one hypothetical divergence scenario tested with AMOVA. The a priori regions are separated by three hypothesized phylogeographical breaks, including (1) current taxonomy, (2) isolation of Cabo region after oceanic inundation of the Isthmus of La Paz, and (3) each sierra as unique genetic entity. Arrows indicate species or sierras as follows: SL, Sierra Laguna; SM, Sierra Mechudo; SSP, Sierra San Pedro; SSF, Sierra San Francisco; SLI, Sierra Libertad; SA, Sierra Asamblea; Cat, Cataviña; SSPM, Sierra San Pedro Martir; SJ, Sierra Juarez; and final tenth group GI, Guadalupe Island. Lower left panel: results of analysis of molecular variance (AMOVA) comparison of three vicariance scenarios, based on nuclear markers. Lower right panel: picture of one of the sampling sites of B. armata in Sierra Asamblea (SA)

Location of the study area showing: (a) Regional topography with focus areas in northern Sierra Leone and Southern Sierra Leone defined by rectangles; (b) Focus areas in northern Sierra Leone (Scarcies River Estuary and Sierra Leone River Estuary) with multiple buffers extending inland from the estuary boundary; (c) Focus areas in southern Sierra Leone (Yawri Bay and Sherbro River Estuary) with multiple buffers extending inland from the estuary boundary; (d) Location of Sierra Leone in West Africa.

Map showing the sampling sites of Washingtonia spp. and Brahea spp. used in our study. The sampling and distributional limits of W. filifera were restricted only to the Mexican populations in Sierra Juarez. Abbreviations correspond to the names of the sampled sierras (populations): SL, Sierra La Laguna; SM, Sierra Mechudo; SG, Sierra Giganta; SSP, Sierra San Pedro; SSF, Sierra San Francisco; SLI, Sierra Libertad; SA, Sierra Asamblea; Cat, Cataviña; SSPM, Sierra San Pedro Martir; SJ, Sierra Juarez; GI, Guadalupe Island and SON, Mexican mainland

Map of Sierra Leone showing District and Chiefdom Borders. Map source: https://commons.wikimedia.org/wiki/File:Districts_in_Sierra_Leone_2018.svg.