Concoctio

A monotypic genus. Brown (1974) speculated, based on morphology and placement of the genus in the Amblyoponinae, that this ant is a predator of some member of the arthropodan forest-floor microgenton.

Identification
Brown's (1974) diagnosis of the single species in this genus also allows for separating this genus from other closely related genera: Concoctio concenta differs sharply from other Amblyoponini (now =Amblyoponinae), the tribe to which it belongs, in the form of the mandibles. The 9-merous antennae are also unique in the tribe, although Amblyopone degenerata (=Stigmatomma degeneratum) has only 7 segments in the antennae. The strongly constricted worker trunk, sharply marginate anterior pronotal border, and spurless middle and hind legs are also distinctive characters, not found in this combination in other Amblyoponini. The name refers to the mixture of characters of Amblyopone (now Amblyopone and Stigmatomma) and Typhlomyrmex; the shape of the mandibles and the overall habitus are at first glance like those of the neotropical genus Typhlomyrmex. Though Concoctio is clearly an amblyoponine, and only convergent to Typhlomyrmecini, it does point to the possibility that the latter stock could have risen from an amblyoponine ancestor by a few rather simple evolutionary steps.

Distribution
Known from Gabon and Zanzibar Island (Tanzania).

Castes
Males have not been collected for the single species in this genus.

Nomenclature

 *  CONCOCTIO [Amblyoponinae]
 * Concoctio Brown, 1974d: 29. Type-species: Concoctio concenta, by original designation.

Worker
Very small in size, total length slightly over 2 mm; apparently monomorphic. Related to Amblyopone and Prionopelta; habitus that of a small, stout species in one of these genera.

Antennae 9-merous with 4-merous club, inserted behind broad clypeus and thus well back of anterior margin of head. Free margin of clypeus with a small rounded median lobe bearing a few blunt teeth. Mandibles triangular, with distinct basal borders curving sharply into edentate apical borders; apical tooth stout, acute, projecting beyond masticatory border and separated from it by a small cleft. Frontal lobes short, contiguous. Eyes reduced to 2-4 weakly pigmented ommatidia situated slightly behind middle of sides of head.

Pronotum with anterior border produced to form a curved over-hanging rim or margin. Promesonotal suture distinct and apparently flexible; metanotal groove present as an impressed line, and just in front of this, the trunk is deeply constricted as seen from above, in the manner of some Centromyrmex and Cryptopone species. Dorsal f ace of propodeum rounded into declivity. Propodeal spiracle round, situated at mid-height of posterior trunk. Legs short, robust. Tibial spur of anterior leg broad and pectinate, but distinguishable spurs are lacking on middle and hind legs. Tarsal claws short, simple.

Petiole and gaster formed as in Amblyopone, the petiole with a brief peduncle that broadens from its insertion caudad and slopes upward as the anterior f ace of the node. Petiole broadly attached to first (postpetiolar) segment of gaster; constriction between postpetiole and remainder of gaster distinct. Sting long and curved.

Body generally shining, but less so on dorsum of head, due to dense small piligerous punctures there, the punctures becoming smaller and less crowded as one passes caudad on body. Hairs short and fine, obliquely erect, abundant over most body surfaces, sparser on mesonotum, rare on mesopleura, coxae and propodeum, which are glabrous. Color yellow.

Queen
dealate: Like worker, and only slightly larger, but with distinct, though modest-sized, multifacetted compound eyes situated behind middle of sides of head. Ocellar triplet present. Pterothorax well-developed, convex, rounded into propodeal declivity, giving trunk a convex outline in side view.