Diversity and Distribution of the Dominant Ant Genus Anonychomyrma (Hymenoptera: Formicidae) in the Australian Wet Tropics

Lily Leahy,Alan N. Andersen,Brett R. Scheffers,Stephen E. Williams

doi:10.3390/d12120474

Lily Leahy, Alan N. Andersen + Show 2 more

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https://doi.org/10.3390/d12120474

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Abstract

Anonychomyrma is a dolichoderine ant genus of cool-temperate Gondwanan origin with a current distribution that extends from the north of southern Australia into the Australasian tropics. Despite its abundance and ecological dominance, little is known of its species diversity and distribution throughout its range. Here, we describe the diversity and distribution of Anonychomyrma in the Australian Wet Tropics bioregion, where only two of the many putative species are described. We hypothesise that the genus in tropical Australia retains a preference for cool wet rainforests reminiscent of the Gondwanan forests that once dominated Australia, but now only exist in upland habitats of the Wet Tropics. Our study was based on extensive recent surveys across five subregions and along elevation and vertical (arboreal) gradients. We integrated genetic (CO1) data with morphology to recognise 22 species among our samples, 20 of which appeared to be undescribed. As predicted, diversity and endemism were concentrated in uplands above 900 m a.s.l. Distribution modelling of the nine commonest species identified maximum temperature of the warmest month, rainfall seasonality, and rainfall of the wettest month as correlates of distributional patterns across subregions. Our study supported the notion that Anonychomyrma radiated from a southern temperate origin into the tropical zone, with a preference for areas of montane rainforest that were stably cool and wet over the late quaternary.

Highlights

The ubiquity, high species richness, and ecological dominance of ants make them model organisms for understanding spatial patterns of diversity and community assembly [1]
Ant distribution is tightly coupled to climate [2], so that an understanding of ant species distributions across climatic gradients provides clues as to how ectothermic species coped with climatic conditions in the past and provides important insights into how they are likely to respond to a future climate
The genus is a member of an Australian dolichoderine subgroup that is thought to be of Gondwanan origin and that most likely originated in Australia approximately

Summary

Introduction

The ubiquity, high species richness, and ecological dominance of ants make them model organisms for understanding spatial patterns of diversity and community assembly [1]. Anonychomyrma Donisthorpe 1947 is an ecologically dominant ant genus in relatively cool and mesic habitats of Australia and New Guinea, extending northwest into Southeast Asia and east to the Solomon Islands [3]. Anonychomyrma is common in heathlands, woodlands, and open of temperate southern Australia ([7,8]; in both referenced articles, the genus is referred to as the forests of temperate southern Australia ([7,8]; in both referenced articles, the genus is referred to as nitidiceps group of Iridomyrmex) and in rainforest of subtropical and tropical mountains of Queensland the nitidiceps group of Iridomyrmex) and in rainforest of subtropical and tropical mountains of and New Guinea [5,9,10]. Most species in drier habitats nest in the ground, whereas rainforest species

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