Agroecomyrmecinae

The only genus of this subfamily, Tatuidris, is monotypic. Tatuidris tatusia occurs in the northern half of South America and through Central America to southern Mexico.

Identification
Bolton (2003) provided the following diagnosis for the subfamily. At the time, the best evidence suggested this was a myrmicomorph subfamily but subsequent molecular analysis revealed it to be a poneriod subfamily.

Mandibles large, masticatory margins oppose at full closure but do not overlap (note 1). Eye at extreme posterior apex of deep antennal scrobe (note 2). Clypeus very broadly triangular, broadly inserted between frontal lobes. Antennal sockets (and frontal lobes) strongly migrated laterally, far apart and close to lateral margins of head (note 3). Mesotibia and metatibia each with a pectinate spur. Alitrunk very short and compact. Petiole sessile; in posterior view the tergite and sternite not forming a circle. Abdominal segment III (postpetiole) without tergosternal fusion; segment large and very broadly articulated to segment IV. Helcium in frontal view with sternite bulging ventrally and overlapped by the tergite, sternite attached to tergite some distance up the inner tergal surface (note 4). Abdominal segment IV with complete tergosternal fusion (note 5), with stridulitrum on pretergite. Sternite of abdominal segment IV reduced, tergite much larger than sternite and strongly vaulted (note 6).

Notes

(1) Mandibles that do not overlap at full closure are also characteristic of the dacetine tribe group and the isolated genus Lenomyrmex. These are certainly convergences as Tatuidris is otherwise very different morphologically and lacks Myrmicinae and dacetine tribe group apomorphies.

(2) Among the Myrmicinae eyes also occur at the apex of the scrobe only in some species of Cephalotes.

(3) Antennal sockets that are close to the lateral margins of the head also occur in the dacetine tribe group and in Cataulacini. In the former this is the result of narrowing of the anterior portion of the head, not of outward migration of the sockets which remain relatively close together. In Cataulacus the position of the sockets has been acquired by a parallel evolutionary process from a very different basic cephalic morphology.

(4) In other words the helcium here resembles that of the poneromorphs, which is also the generalised state prevalent throughout the Formicidae; see notes under dorylomorph subfamilies.

(5) With the exception of the strange amblyoponine genus Adetomyrma, tergosternal fusion of abdominal segment IV is otherwise universal only in the poneromorphs. Fusion of this segment in agroecomyrmecines is regarded, perhaps incorrectly, as independently evolved here (its presence is of course speculative in the fossil genera). Its only other occurrence is in the myrmicine Ankylomyrma (Ankylomyrmini), where the condition is certainly uniquely derived.

(6) For other reductions of abdominal sternite IV see notes under formicomorph subfamilies.

Nomenclature
Subfamily AGROECOMYRMECINAE Agroecomyrmicini Carpenter, 1930: 34. Type-genus: *Agroecomyrmex. Taxonomic history Agroecomyrmecinae as myrmicomorph subfamily of Formicidae: Bolton, 2003: 51, 181. Agroecomyrmecinae as poneroid subfamily of Formicidae: Brady, Schultz, et al. 2006: 18173; Moreau, Bell et al. 2006: 102; Ward, 2007a: 555. Tribe: Agroecomyrmecini.