You may remember a recent viral video showing an undescribed predatory ant behavior. It turned out that myrmecologists Christian Peeters and Stéphane de Greef had observed these ants in the field, but they’d not assembled enough data to publish, leaving us all in the dark about how the ants coordinated the amazing millipede-hauling chains.
A monumental day for ant taxonomy! The mythical Schmidt & Shattuck ponerine revision, long rumored to be in the works, has emerged from the mists of legend and lore. It’s real! All 242 pages are in Zootaxa:
I don’t wish to speak for the entire myrmecological community, but I think it is safe to say that Chris Schmidt and Steve Shattuck’s ponerine revision has been the most awaited taxonomic paper of the past decade. Ponerine ants comprise one of the greatest subfamilies in terms of abundance and species diversity, particularly in the tropics. Ant people know ponerines. The group is the most purely predatory of the large subfamilies and contains some spectacular insects: trap-jaw ants, matabele ants, various and sundry predators and huntress ants.
Schmidt & Shattuck’s paper is significant for two reasons. First, nearly all ant researchers will be affected by the taxonomic changes. And second, the changes themselves are large, especially for the hundreds of species that used to belong to the sprawling polyphyletic genus Pachycondyla. Under the Schmidt & Shattuck hammer, Pachycondyla in the strict sense remains just a shadow. All but a handful of Neotropical species move to 19 different genera, some new, most revived from older literature. There are about a third more ponerine genera to learn than there were yesterday. That’s a lot to digest.
You might think such large changes would invite controversy, but I anticipate that the new scheme will be widely accepted and largely stable.
1. The work itself is thorough, involving morphology and several different genetic markers. There is good reason this paper was years in the making.
2. Many of the newly valid names are resurrected from the older literature, and as such they already reflect gross morphological groupings as seen by earlier generations of myrmecologists.
3. Ant taxonomists are more uniformly phylogenetic in their outlook than the preceding cohort. The polyphyly of Pachycondyla was not an accident born of ineptitude; rather, it was designed that way by Bill Brown, who was operating under a different philosophy of systematics more popular in the middle of the last century. Since Brown’s school has faded from prominence, most biologists are uncomfortable with polyphyly. As Schmidt & Shattuck are dragging ponerine taxonomy back into the comfort zone of most evolutionary biologists, I expect the new scheme will be popular.
In the big picture, Schmidt & Shattuck have put this important group of ants on a stronger taxonomic foundation. In the small picture, we are faced with the mundane realities of re-memorization.
Pachyondyla apicalis? No longer. Get used to Neoponera apicalis. Pachycondyla stigma? Nope. It’s Pseudoponera stigma. Plus, there’s Brachyponera, Pseudoneoponera, Mesoponera…
The first time I saw Typhlomyrmex in the field, in a Paraguayan forest, I had no idea what I was looking at. Strange reddish ants crawling around in hard, dead wood. Putting the ants under the scope didn’t help, either. The mystery animals could have belonged to any number of poneromorph subfamilies. I eventually keyed them to genus. Unexpectedly, Typhlomyrmex are in the Ectatomminae, a subfamily better known for large, colorful surface-foraging ants like Ectatomma and Rhytidoponera.
In any case, I have finally gotten around to creating a gallery to hold the handful of photographs I have of this enigmatic genus. Take a look:
When I first saw the following figure, presented by myrmecologist Chris Schmidt at a social insect conference, the whole room broke into laughter:
Pachycondyla, among the most common ants in tropical regions worldwide, turns out to be a motley assortment of unrelated species. While the taxonomy of the world’s 12,000 or so ant species is obviously still a work on progress, I don’t think any of us had seen a case where ant names showed such a non-relationship to their genealogy. We knew before that Pachycondyla wasn’t really a natural group. But this? This was bad.
I’m writing this post because Chris has just published his study in Zootaxa, and while the paper is behind a subscription barrier, the data and tree are available for free on Treebase. A follow-up paper is also in the works to bring the taxonomy into line with what is known from ant phylogenetics. Most Pachycondyla will likely revert to older names (Neoponera, Bothroponera, etc.), with only a handful of Neotropical species- including P. striata, above- remaining in a reduced Pachycondyla.
Thanks to myrmecologist Benoit Guenard, I recently had the opportunity to photograph live Pachycondyla chinensis in a laboratory setting. This species- sometimes called the Asian Needle Ant- was introduced accidentally to the southeastern United States over half a century ago, and where it occurs it seems to displace many native ants.
What is particularly odd about the displacement is that P. chinensis is primarily a termite predator. I wouldn’t expect a dietary specialist to have much effect on a more generalist native fauna, yet it does. Fortunately, the ecology of the invasion is the subject of active research by Benoit and others.
I found that placing live Reticulitermes termites near a hungry needle ant nest fragment induced reliable predation behavior, enough to capture a series of photographs, below:
Canon MP-E 65mm 1-5x macro lens on a Canon EOS 50D
ISO 100, f/13, 1/250 sec, diffused twin flash
substrate is white mylar
Thaumatomyrmex is a rarely seen spider-like ponerine ant of Neotropical forests. These beguiling insects are specialized predators of spiny polyxenid millipedes, and their pitch-fork jaws allow the ants to keep prey at a distance while carefully stripping away the spines.
Canon MP-E 65mm 1-5x macro lens on a Canon EOS 20D
ISO 100-200, 1/200sec, f/13
twin flash diffused through tracing paper
Barry Bolton and Brian Fisher have revised the African ponerine genus Phrynoponera, in a monograph appearing today in Zootaxa. Phrynoponera are stout, heavily-armored predatory ants comprising a handful of poorly known species. Bolton and Fisher describe two new species, P. pulchella and P. transversa, to bring the tally of known species to five.