Octostruma iheringi

From the Ants of Costa Rica website description: "Face longitudinally rugulose, with 8 erect spatulate setae; mesosomal and gastral dorsa lacking erect setae; one or two stiff setae projecting from posterior face of hind coxa, a long, fine, flexuous seta projecting laterally from near spiracle on peduncle of petiole, fine seta projecting anteroventrally from anterolateral border of postpetiole (figure; Brown and Kempf discovered these setae and proposed a sensory function; I have not seen them on any other Octostruma species); color red; HW 0.73 (n=1)."

My specimen seems to fit this description exactly except for the lack of any setae on the head.  HW=0.78mm

Octostruma KTRW-002

Large, HW=0.64mm, ~10 erect spatulate setae on thorax, ~20 erect spatulate setae on face.

Octostruma KTRW-003

Large, HW=0.63mm; no erect spatulate hairs on thorax, but with many suberect setae; face with 6 erect spatulate setae and many subdecumbent hairs; first gastral tergite with 6 erect spatulate setae.

Octostruma KTRW-004

Large, HW=0.64; first gastral tergite with <or=4 erect spatulate hairs; encrusted with dirt; distinct carina on propodeum between propodeal lobes (see figure). 

Octostruma KTRW-005

Large, HW=0.6mm; first gastral tergite with >12 erect spatulate hairs; indistinct carina on propodeum between propodeal lobes (see figure).

Octostruma KTRW-006

Smaller ant, HW<0.6mm; no erect hairs on thorax; 8 erect spatulate hairs on face (see figure); first gastral segment with 4 erect spatulate setae.

Octostruma KTRW-007

Similar to KTRW-006 with the following differences: thorax with 4 upright spatulate hairs; petiole with 2 upright spatulate hairs; first gastral segment with > 10 upright spatulate hairs; face with 10-12 upright spatulate hairs.

Octostruma KTRW-008

A mixture of KTRW-006 and KTRW-007, with the face and thorax pilosity of KTRW-007 but with the gaster pilosity of KTRW-006.