Evolution of gliding in Southeast Asian geckos and other vertebrates is temporally congruent with dipterocarp forest development

Abstract

).Gliding morphologies occur in diverse vertebrate lineages in Southeast Asian rainforests, including three gecko genera, plus frogs, snakes, agamid lizards and squirrels. It has been hypothesized that repeated evolution of gliding is related to the dominance of Asian rainforest tree floras by dipterocarps. For dipterocarps to have influenced the evolution of gliding in Southeast Asian vertebrates, gliding lineages must have Eocene or later origins. However, divergence times are not known for most lineages. To investigate the temporal pattern of Asian gliding vertebrate evolution, we performed phylogenetic and molecular clock analyses. New sequence data for geckos incorporate exemplars of each gliding genus (Cosymbotus, Luperosaurus and Ptychozoon), whereas analyses of other vertebrate lineages use existing sequence data. Stem ages of most gliding vertebrates, including all geckos, cluster in the time period when dipterocarps came to dominate Asian tropical forests. These results demonstrate that a gliding/dipterocarp correlation is temporally viable, and caution against the assumption of early origins for apomorphic taxa.

How animals glide: from trajectory to morphology

“…This rationale might help to explain the great diversity of gliders in southeast Asia, but many other tall forests have few, if any, gliding vertebrates, suggesting a more complex relationship between habitat structure and gliding behavior. A recent phylogenetic analysis demonstrates the plausibility of a forest-structure explanation for the high diversity of gliders in Southeast Asia (Heinicke et al 2012), but overall, little attention has been paid to this interesting ecophysiological issue.…”

Crossing the line: increasing body size in a trans-Wallacean lizard radiation ( Cyrtodactylus , Gekkota)

“…Similar shifting patterns of ecological diversification and/or species accumulation following overwater dispersal eastwards into Wallacea have been described in other vertebrate lineages [6,8,16]. For example, another trans-Wallacean gecko lineage (Gehyra and allies) comprises a comparatively depauperate fauna of small taxa in Asia, juxtaposed against a younger and morphologically diverse radiation in Australasia-including two lineages that have independently approached large sizes similar to those observed in Cyrtodactylus (more than 140 mm) [16]. Likewise, fanged frogs (Limonectes) show statistically significant evidence for adaptive radiation following overwater colonisation of Sulawesi from the Philippines [8].…”

“…Empirical data suggest that many lineages have undergone ecological release following eastwards dispersal across Wallacea [6,8,16]. However, despite the extensive literature on the biogeography of Wallacea, Cyrtodactylus is currently one of few lineages that provide statistically significant evidence of a shift in evolutionary trajectory related to dispersal into the Australopapuan region.…”

“…These may have constrained the maximum body sizes. Of particular note is a moderately old lineage (20þ mya) of very large geckos (max SVL 185-191 mm) in the genus Gekko that is widespread across Indonesia as far east as Sulawesi and the Lesser Sundas [16,17]. These species are aggressive competitors (and potentially also predators) that use similar microhabitats to the giant Papuan Cyrtodactylus (medium to large trees and tree hollows) but do not overlap in distribution [16,17].…”

“…The Asian region is the area of origin for Cyrtodactylus [9] but is also home to a diversity of other Gekkotan lineages [16,17]. These may have constrained the maximum body sizes.…”