Cladistic biogeography of the Mexican transition zone

Abstract

Biogeographic relationships among nine montane areas of endemism across the transition zone between North and South America are analysed cladistically based on phylogenetic hypotheses of thirty‐three resident monophyletic taxa of insects, fish, reptiles, and plants. Areas of endemism include the Arizona mountains (AZ), Sonoran Desert (SD), Sierra Madre Occidental (OCC), southern Sierra Madre Occidental (SOC), Sierra Madre Oriental (ORI), Sierra Transvolcanica (TRAN), Sierra Madre del Sur (SUR), Chiapan‐Guatemalan Highlands (CGH), and Talamancan Cordillera (TC). Area relationships are summarized using Brooks Parsimony Analysis and Assumption 0, with the former resulting in more defensible biogeographic hypotheses. Areas of endemism are dividable into two monophyletic groups; a northern group including AZ, SD, OCC, and ORI, and a southern group consisting of TC, CGH, TRAN, SUR, and the isolated southern regions of the Sierra Madre Occidental (SOC). The northern set of areas are characterized by recent, probably Pleistocene, isolation and prevalent widespread species, whereas the southerly areas probably diverged after Pliocene closure of the Panamanian isthmus. The southern areas are redundantly represented on many of the taxon‐area cladograms by endemic species, indicative of much higher levels of endemism in the Sierra Transvolcanica and further south. Use of a general area cladogram in such a transition zone permits explicit exploration of biogeographic patterns and establishes a predictive framework for taxonomy and conservation prioritization.

A biophysical perspective on dispersal and the geography of evolution in marine and terrestrial systems

“…Analytical approaches in, for example, biogeography are equally applicable to data from marine and terrestrial systems (e.g. Marshall & Liebherr 2000;Santini & Winterbottom 2002;Wojcicki & Brooks 2005; but see Siddall 2005), and the coupled biophysical models increasingly employed to study dispersal of marine larvae (e.g. Cowen et al 2000Cowen et al , 2006Galindo et al 2006) can be expected to promote similar approaches to studying aerial dispersal (e.g.…”

When island-like populations at high elevation show genetic divergence despite no morphological variability: the case of Lupinus montanus in Central Mexico

“…These 2 volcanoes are the youngest of the TMVB, being formed during the late Pleistocene (Hoskuldsson, 1992;Macias, 2007). As a result, NT and PO populations experienced more recent and intense volcanic activity (García-Palomo et al, 2002;Macias, 2007), potentially restricting gene flow among populations even more than among the older volcanoes (LM, AJ, NC, and IZ were formed from the Oligocene to the early Pleistocene; see Marshall and Liebherr, 2000). On average, the pairwise F ST values are higher between populations on young volcanoes than between populations on older volcanoes (0.39 and 0.32, respectively).…”

“…Most populations of Lupinus montanus var. montanus are found in the TMVB in Central Mexico, with an island-like distribution across a series of more or less isolated volcanoes of different origins, from the Quaternary (e.g., Pico de Orizaba and Nevado de Toluca) or the Tertiary (e.g., Iztaccihuatl and La Malinche) (Marshall and Liebherr, 2000). This pattern of distribution may represent a factor of diversification and differentiation, which is impossible to detect using purely morphological characters (Dunn and Harmon, 1977).…”

Historical Biogeography of the Livebearing Fish Genus Poeciliopsis (Poeciliidae: Cyprinodontiformes)

“…Central America and Mexico comprise a tectonically and volcanically dynamic part of the world that has interested biogeographers for many years (Marshall and Liebherr 2000). This diverse region has served as a corridor for organismic dispersal between the Neartic and Neotropic and represents a transition zone between these provinces (Pielou 1979).…”