Independent Transitions between Monsoonal and Arid Biomes Revealed by Systematic Revison of a Complex of Australian Geckos (Diplodactylus; Diplodactylidae).

Paul M Oliver,Mitzy Pepper,Patrick J Couper,Matthias Stöck

doi:10.1371/journal.pone.0111895

Paul M Oliver, Mitzy Pepper + Show 2 more

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https://doi.org/10.1371/journal.pone.0111895

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Abstract

How the widespread expansion and intensification of aridity through the Neogene has shaped the Austral biota is a major question in Antipodean biogeography. Lineages distributed across wide aridity gradients provide opportunities to examine the timing, frequency, and direction of transitions between arid and mesic regions. Here, we use molecular genetics and morphological data to investigate the systematics and biogeography of a nominal Australian gecko species (Diplodactylus conspicillatus sensu lato) with a wide distribution spanning most of the Australian Arid Zone (AAZ) and Monsoonal Tropics (AMT). Our data support a minimum of seven genetically distinct and morphologically diagnosable taxa; we thus redefine the type species, ressurrect three names from synonymy, and describe three new species. Our inferred phylogeny suggests the history and diversification of lineages in the AAZ and AMT are intimately linked, with evidence of multiple independent interchanges since the late Miocene. However, despite this shared history, related lineages in these two regions also show evidence of broadly contrasting intra-regional responses to aridification; vicarance and speciation in older and increasingly attenuated mesic regions, versus a more dynamic history including independent colonisations and recent range expansions in the younger AAZ.

Highlights

The extent and intensity of arid conditions in the Southern Hemisphere has increased through the late Neogene, and expansive deserts are a prominent feature of most southern continents (Africa, Australia and South America) [1,2,3,4]
We a) contrast genetic diversity in the two regions, and b) use simple ancestral state reconstruction to assess the frequency and trajectory of shifts between biomes. Based on these data we present a revised taxonomy, formally recognizing seven of the lineages identified by Oliver et al [29] as species and thereby add six further species to the diverse Australian lizard fauna
This study utilised specimens and tissues held in the Australian Museum (AMS), National Museum of Victoria (NMV), Northern Territory Museum and Art Gallery (NTM), Queensland Museum (QM), South Australian Museum (SAMA) and Western Australian Museum (WAM)

Summary

Introduction

The extent and intensity of arid conditions in the Southern Hemisphere has increased through the late Neogene, and expansive deserts are a prominent feature of most southern continents (Africa, Australia and South America) [1,2,3,4]. These generally young arid zones are characterised by low, unpredictable rainfall and strong seasonal variation in temperature, and this major climatic shift has had profound biological implications; some lineages have adapted to PLoS ONE | DOI:10.1371/journal.pone.0111895. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

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