1.3: Systematics of the large and diverse ant genus Iridomyrmex
Iridomyrmex is the "Eucalyptus" of the invertebrate world, occurring throughout Australia in exceptionally high densities and being hyper-diverse with many hundreds of species (most undescribed). However, the genus is morphologically uniform and lacks conspicuous morphological characters. This has hampered serious taxonomic work on the group and resulted in a poor understanding of the species present.
This project will provide, for the first time; a species-level taxonomic understanding of this group. Hypotheses of species boundaries and intraspecific variation will be framed using phenotypic data and these will then be tested using multiple molecular markers from mitochondrial and nuclear DNA.
Traditional morphological analyses will be combined with molecular techniques to provide data necessary to complete a robust revision of Iridomyrmex. Specimens held in collections throughout Australia will be examined to ensure the broadest possible sampling of this diverse genus.
This project is a collaboration between Curtin University of Technology and the Australian National Insect Collection, with input from a wide range of systematists and ecologists from throughout Australia and overseas.
Tools for Decision Makers
The results of this research will be published using a variety of methods, including traditional peer-reviewed paper-based journals and a variety of web sites. The primary web delivery will focus on expanding the current website Australian Ants Online and establishing the site as a web atlas at species level.
The morphological analysis for the entire genus has been completed and a manuscript based on this data is undergoing an external review process. Specimen data collected during the life of this project has been checked for quality and errors rectified.
The detailed knowledge gained during the Iridomyrmex work provides both immediate and long term benefits. In the short term, specimens can be identified to species while in the longer term this project has identified a number of complex taxonomic problems that warrant additional study. An example of unexpected complexity is a set of morphologically similar specimens which show strong genetic divergence based on DNA sequencing. Identifying and solving problems such as this will further enhance our understanding of this diverse group.
Additional web-based reports have been added to the publicly available web site for ants (http://anic.ento.csiro.au/ants/biota_details.aspx?BiotaID=35719) which serves the data generated during this project. These reports have been based directly on feedback from users.
Databasing of the Curtin University of Technology Ant Collection has been completed. Databasing of the CSIRO TERC collection is underway and arrangements have begun to capture specimen data held by the Queensland Museum. Over 50,000 specimen records were added to the ANIC specimen database and made available to clients.
Taxonomic research on the ant genus Iridomyrmex has revealed that the group contains approximately 80 species, 35 of which are new to science. To document these species, approximately 40,000 specimens from throughout Australia, South-east Asia and the South Pacific have been examined, and over 200 samples subjected to DNA analysis. Images, descriptions and distribution maps have been prepared for all species, as well as a key to their identification. This key is now being reviewed by external users and feedback will improve its quality and useability. This information is being made available on the Ants Down Under web site (http://anic.ento.csiro.au/ants/ ). We now have a good understanding of the identity and relationships among these common and important Australian insects.
Ants are everywhere and one particularly prolific group of Australian ants is the genus Iridomyrmex, familiar to many Australians because it contains the meat ants.
Although Iridomyrmex occurs throughout Australia and is one of the largest, most ecologically important and common groups of Australian ants, its taxonomy is yet to be properly unravelled. Until this is done it will be very difficult to reliably identify many species.
The first species-level revision to produce an accurate description of all the Iridomyrmex species in this important Australian ant genus is based on both morphology (the physical structure) and molecular data. Through careful examination and interpretation of key morphological features, we have been able to gain greater understanding of the genus to define species boundaries and develop descriptions and keys for identification.
Our revision has raised issues in interpretation of previous species concepts, matching these to existing published names, and delimiting new species. For example, of the 81 species names currently available, 63 refer to 'good' taxa which are clearly distinguishable, while another 18 names represent common, widespread species which have been previously described under earlier names. In addition, the project has identified 37 new species which currently lack names, and will be formally described in the near future. This brings the total number of Australian Iridomyrmex species to around 100.
A preliminary key has been completed, while illustrations are currently being produced and a molecular phylogeny (genetic evolutionary tree) is being constructed.
Non-taxonomic specialists, such as ecologists, land managers and environmental specialists will benefit from a field guide to all of the Iridomyrmex species that is being developed. This guide will be electronically generated on demand using the most up to date information available. It will include the ability to search information for species local to a specific region, greatly simplifying the field guide and targeting it to local users.