Myrmicine ants are a mess. The subfamily Myrmicinae holds about half of all ant species and includes fire ants, harvester ants, leafcutter ants, turtle ants, and many more. Attempts to arrange the diversity into workable subgroups have been difficult and largely unsatisfying. Many species stubbornly show traits of several groups at once. Molecular trees (Moreau 2006, Brady et al 2006) have reflected this uncertainty, recovering only a few reliable clades among a statistically uncertain base.
Consider the tribe Stenammini (sensu Bolton 2003) laid over Corrie Moreau’s 2006 molecular chronogram of the subfamily:
There is certainly no molecular signature for Stenammini as a group. As we can see, the four included species do not group together. What’s more, the morphological traits defining Stenammini- like a 12-segmented antenna with a 3-segmented club- are mostly just the pleisiomorphic base states for ants. So morphology doesn’t give us compelling reasons to accept Stenammini either. If we accept this pattern, Stenammini appears to be a random draw of myrmicine ants that retain an arbitrary set of ancestral characters.
I bring this up because of Boltonidris, a new fossil ant genus described a couple weeks ago by Radchenko and Dlussky and painstakingly placed in the Stenammini:
Abstract: The new extinct ant genus and species, Boltonidris mirabilis, are described from the late Eocene Rovno Amber (Ukraine). This genus belongs to the tribe Stenammini of the subfamily Myrmicinae. It possesses the plesiomorphic characters of the tribe Stenammini, e.g. 12-segmented antennae with 3-segmented apical club, characteristic structure of the clypeus and frontal lobes, absence of gastral shoulder, but it has a series of autapomorphies, e.g. modified mandibles with the only two teeth on the masticatory margin, well developed longitudinal medial groove on the head dorsum, somewhat depressed areas lateral to the frontal carinae (like “vestigial” antennal scrobes), and finely swollen postero-lateral area of head, close to the occipital corners. Additionally, it has two short blunt teeth on the pronotum.
Here’s a pic:
The descriptive work in the paper is solid, and it looks to my untrained eye like this ant deserves the new taxon. So the paper is a valuable contribution.
Yet Radchenko and Dlussky spend much of their discussion relating Boltonidris to other Stenammini, with no mention that the two most ambitious attempts to resolve myrmicine relationships to date (Moreau 2006 and Brady et al 2006) both concluded Stenammini didn’t exist. Thus, theirs reads like a discussion to determine which pinhead is most likely to have to staged dancing angels. Pointless.
If taxonomists aren’t going to read each other’s research, why even bother publishing?
Bolton B (2003) Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute, 71: 1–370.
Brady SG, Fisher BL, Schultz TR, Ward PS (2006) Evaluating alternative hypotheses for the early evolution and diversification of ants. Proc Natl Acad Sci USA 103:18172–18177.
Moreau CS, Bell CD, Vila R, Archibald SB, Pierce NE (2006) Phylogeny of the ants: Diversification in the age of angiosperms. Science 312:101–104.
Radchenko A, Dlussky GA (2012) Boltonidris Gen. Nov., the First Extinct Stenammini Ant Genus (Hymenoptera, Formicidae) from the Late Eocene Rovno Amber. Annales Zoologici 62: 627–631.