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

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.

Anonychomyrma inclinata sp. nov. (Hymenoptera: Formicidae): description, biology and interaction with the endangered bulloak jewel butterfly, Hypochrysops piceatus Kerr, Macqueen & Sands, 1969 (Lepidoptera: Lycaenidae)

“…Although morphology and distribution made A. inclinata unlikely to be among the undescribed Wet Tropics species identified in Leahy et al . (2020), this was confirmed by generating standard cytochrome c oxidase subunit 1 (COI) barcode data for two individuals of A. inclinata for comparison with those of the undescribed Wet Tropics species. Both sequences were identical, and no match was found with the Leahy et al .…”

“…Both sequences were identical, and no match was found with the Leahy et al . (2020) species, A. inclinata having a COI sequence 11.9% divergent from the most similar Wet Tropics species. The COI data for the specimens (ANIC 32‐146120) are available on GenBank (accession number MZ313336).…”

“…In addition, recent work in the Queensland wet tropics using genetic and morphological data suggested that the genus includes significant unrecognised diversity; 20 undescribed species were identified (Leahy et al . 2020). Under these circumstances, a full revision of the genus prior to the description of a single new species would normally be warranted.…”

Diversity, Biogeography and Community Ecology of Ants: Introduction to the Special Issue

“…Three papers [1][2][3] make a significant contribution to our understanding of undocumented ant diversity. Two of these [1,2] are from Australia, illustrating the extent to which the remarkably megadiverse ant fauna of this continent remains undocumented.…”

“…Three papers [1][2][3] make a significant contribution to our understanding of undocumented ant diversity. Two of these [1,2] are from Australia, illustrating the extent to which the remarkably megadiverse ant fauna of this continent remains undocumented. One relates to a large and conspicuous 'species' of the arid-adapted formicine genus Melophorus that is endemic to Australia [1].…”