Phylogenetics of Fanged Frogs: Testing Biogeographical Hypotheses at the Interface of the Asian and Australian Faunal Zones

Abstract

The interface of the Asian and Australian faunal zones is defined by a network of deep ocean trenches that separate intervening islands of the Philippines and Wallacea (Sulawesi, the Lesser Sundas, and the Moluccas). Studies of this region by Wallace marked the genesis of the field of biogeography, yet few workers have used molecular methods to investigate the biogeography of taxa whose distribution spans this interface. Some taxa, such as the fanged frogs of the ranid genus Limnonectes, have distributions on either side of the zoogeographical lines of Wallace and Huxley, offering an opportunity to ask how frequently these purported barriers were crossed and by what paths. To examine diversification of Limnonectes in Southeast Asia, the Philippines, and Wallacea, we estimated a phylogeny from mitochondrial DNA sequences obtained from a robust geographic sample. Our analyses suggest that these frogs dispersed from Borneo to the Philippines at least twice, from Borneo to Sulawesi once or twice, from Sulawesi to the Philippines once, and from the Philippines to Sulawesi once. Dispersal to the Moluccas occurred from Sulawesi and to the Lesser Sundas from Java/Bali. Species distributions are generally concordant with Pleistocene aggregate island complexes of the Philippines and with areas of endemism on Sulawesi. We conclude that the recognition of zoogeographic lines, though insightful, may oversimplify the biogeography of widespread taxa in this region.

Vicariance and marine migration in continental island populations of a frog endemic to the Atlantic Coastal forest

“…This isolation scenario seems to hold for some continental island dwelling amphibians: a recent study of fire salamanders showed a reduction of genetic diversity on insular populations indicating that these populations evolved in isolation without any subsequent marine dispersal events (Velo-Antón et al, 2012). However, some studies indicate that amphibians are in fact able to disperse to islands (Seppa and Laurila, 1999;Evans et al, 2003;Vences et al, 2003), although the exact mechanism of dispersal is unknown. In this study, we examine the population genetics of Thoropa taophora, a frog species endemic to the Atlantic Coastal Forest of Brazil (Feio et al, 2006) that inhabits rocky coastal shores and has some physiological tolerance to seawater (Bokermann, 1965;Sazima, 1971;Abe and Bicudo, 1991;Brasileiro et al, 2010).…”

High level of cryptic species diversity revealed by sympatric lineages of Southeast Asian forest frogs

“…To date, every molecular genetic study that has broadly sampled populations across the range of a widespread frog species in Southeast Asia (southern China to Sulawesi) has uncovered genetic diversity interpreted by those authors as unrecognized species diversity (Toda et al 1998;Emerson et al 2000;Li et al 2001a,b;Matsui et al 2001;Veith et al 2001;Brown & Guttman 2002;Bain et al 2003;Evans et al 2003;Matsui et al 2005). Seven of these ten studies involved frog species that live only in intact forest.…”

A coalescent framework for comparing alternative models of population structure with genetic data: evolution of Celebes toads

“…Cryptic fragmentation has been proposed on the Indonesian island of Sulawesi based on similar patterns of diversity in multiple groups, including the Celebes toad (Evans et al 2003c), monkeys (Evans et al 2003b), fanged frogs (Evans et al 2003a) and flying lizards (McGuire et al 2007). However, the validity of a demographic model of isolation by distance (IBD) plus fragmentation as opposed to a model of exclusively IBD has been questioned (Bridle et al 2004).…”