Lizards of the lost arcs: mid-Cenozoic diversification, persistence and ecological marginalization in the West Pacific

Abstract

Regions with complex geological histories often have diverse and highly endemic biotas, yet inferring the ecological and historical processes shaping this relationship remains challenging. Here, in the context of the taxon cycle model of insular community assembly, we investigate patterns of lineage diversity and habitat usage in a newly characterized vertebrate radiation centred upon the world's most geologically complex insular region: island arcs spanning from the Philippines to Fiji. On island arcs taxa are ecologically widespread, and provide evidence to support one key prediction of the taxon cycle, specifically that interior habitats (lowland rainforests, montane habitats) are home to a greater number of older or relictual lineages than are peripheral habitats (coastal and open forests). On continental fringes, however, the clade shows a disjunct distribution away from lowland rainforest, occurring in coastal, open or montane habitats. These results are consistent with a role for biotic interactions in shaping disjunct distributions (a central tenant of the taxon cycle), but we find this pattern most strongly on continental fringes not islands. Our results also suggest that peripheral habitats on islands, and especially island arcs, may be important for persistence and diversification, not just dispersal and colonization. Finally, new phylogenetic evidence for subaerial island archipelagos (with an associated biota) east of present-day Wallace's Line since the Oligocene has important implications for understanding long-term biotic interchange and assembly across Asia and Australia.

Parachute geckos free fall into synonymy:Gekkophylogeny, and a new subgeneric classification, inferred from thousands of ultraconserved elements

“…Our phylogenomic estimate of selected Gekko taxa both confirms previous findings of paraphyly with respect to Ptychozoon and some species of Luperosaurus (Brown et al, 2012a, b;Heinicke et al, 2012) and provides new insight into the evolution of morphological novelty within gekkonid lizards (Gamble et al, 2012;Oliver et al, 2018). Although Gekko is known to be a phenotypically variable, highly diverse clade (Rösler et al, 2011), with some clades more variable than others, none exhibit more structural body plan novelty than members of the genus Ptychozoon (Brown et al, 1997;Russell et al, 2001).…”

“…For example, lineages of Luperosaurus not only appear to render Gekko, but also Lepidodactylus (not considered here), paraphyletic (Heinicke et al, 2012;Oliver et al, 2018). To date, phylogenetic analyses that include taxa outside of Gekko have led to unclear taxonomic boundaries, nomenclatural instability, and frequent transfers of taxa between genera (Russell, 1979;Rösler et al, 2012;Brown et al, 2000Brown et al, , 2007Brown et al, , 2012a.…”

“…Our taxon sampling was selected to resolve a polytomy consisting of several clades assigned to the genera Gekko, Luperosaurus, and Ptychozoon (Brown et al, 2012a). Issues relating to the relationships of some Luperosaurus, Lepidodactylus, and Pseudogekko taxa (Heinicke et al, 2012;Oliver et al, 2018) are the focus of a different study and will be discussed elsewhere.…”

“…While this manuscript was in preparation, a series of three papers appeared (Hoser, 2018a, b, c,) in which revised taxonomies were presented for Gekko, Luperosaurus, and Ptychozoon, as well as Lepidodactylus and Pseudogekko. The basis for these papers were the various publications cited herein (e.g., Rösler et al, 2011;Brown et al, 2012a, b;Heinicke, 2012;Oliver et al, 2018) in which phylogenetic hypotheses based on Sanger sequencing results were presented, without concomitant taxonomic rearrangements, pending the collection of data which would permit more advanced analyses, and well-supported topologies (this work). Hoser (2018a, b, c) proposed several new generic and subgeneric names to deal with cases of paraphyly and polyphyly as they were understood and misunderstood by him, prior to the present study.…”

“…Additionally, he proposed numerous new species names, based on unsubstantiated (i.e., presented without accompanying data from voucher specimens) and operationally non-diagnostic "diagnoses" based, apparently, on "character states" gleaned from figures/photographs included in Brown et al (2012a, b), Heinicke et al (2012), and Oliver et al (2018). Aside from his disregarding of conventions of species descriptions, some of his higher taxonomic proposals are partly, though not entirely, congruent with the units recognized herein and also include some generic proposals that our current data suggest are non-monophyletic.…”