Older than the islands: origin and diversification of Galápagos leaf‐toed geckos (Phyllodactylidae: Phyllodactylus) by multiple colonizations

Abstract

Aim We re‐examine the biogeography of the leaf‐toed geckos (Phyllodactylus) endemic to the Galápagos Islands. Our aim was to (1) test the multiple‐colonization hypothesis against the single‐colonization scenario proposed for most terrestrial organisms in the archipelago, (2) estimate the age of colonization of Phyllodactylus, and (3) evaluate the roles of dispersal and vicariance in the evolution of these lizards. Location Galápagos archipelago, Ecuador. Methods Phylogenetic relationships were evaluated with maximum‐likelihood and Bayesian methods, including the estimation of divergence times and species trees. Previous biogeographical hypotheses were evaluated with tree‐topology tests. Results Our results support a multiple‐colonization scenario: all but one species of Phyllodactylus in the Galápagos Islands belonged to a single radiation. The founders of this radiation colonized the archipelago 13.2 Ma when the islands currently above water had not yet emerged. Ten million years later, the ancestors of Phyllodactylus darwini colonized San Cristóbal. Main conclusions As with other Galápagos organisms, the Pacific coast of South America seems to have been the source for the founders that led to the oldest radiation of leaf‐toed geckos. Unlike most Galápagos endemics, however, P. darwini might have originated in the Andes. Our phylogenetic hypotheses and recent palaeogeographical data support both dispersal and vicariance as mechanisms leading to the radiation of leaf‐toed geckos in the Galápagos Islands.

Island biogeography: Taking the long view of nature’s laboratories

“…Although most of New Zealand's biota appears to owe its origins to dispersal, recent work has identified Zeelandia as a largely drowned continent, including present-day New Zealand and New Caledonia (37). The heated vicariance-dispersalist arguments, so often focused on island systems with continental underpinnings (e.g., New Caledonia, New Zealand, Madagascar) but including even mantleplume hotspot systems [compare (28,29,38)], may thus be superseded by recognizing that an island can host multiple colonizer types (35,39). Given all these processes and sufficient time, we can envisage particular lineages becoming distributed across a set of now far-flung islands by a combination of relatively modest dispersal prowess and excellent persistence.…”

Going under down under? Lineage ages argue for extensive survival of the Oligocene marine transgression on Zealandia

“…The colonization of islands through long‐distance dispersal (LDD) has long been inferred from observation of the rapid establishment of biota on new volcanic islands (Gillespie et al., ), such as Krakatoa, where over 400 species established in the first decade after emergence (Emerson, ). Molecular analysis has been used to determine the origins of lineages on older, larger and more isolated volcanic archipelagos, notably the Galápagos (Torres‐Carvajal, Barnes, Pozo‐Andrade, Tapia, & Nicholls, ), Hawaiian (Wagner & Funk, ) and Canary archipelagos (Juan, Emerson, Oromi, & Hewitt, ). By inference, one might expect the biota of a larger landmass such as New Zealand to have also been strongly influenced by LDD, especially given its relative proximity to Australia compared with smaller, more remote Pacific islands (MacArthur & Wilson, ).…”

Jurassic primates, immobile ducks and other oddities: a reply to Heads’ review of The Monkey’s Voyage

“…(2) A substantial number of oceanic island radiations predate the current islands, indicating colonisation of prior land in the area (e.g. Rassmann 1997;Torres-Carvajal et al 2014;Bradler et al 2015; see Hawaiian section above). These findings indicate the potential complexity of islandcolonisation histories, especially where many former islands existed.…”