Subfamilies
Links
Jack Longino's Ants of Costa Rica
American Museum Social Insects website
William and Emma Mackay Ants of North America site
sF Ectatomminae Gnamptogenys
Gnamptogenys is a speciose genus with lots of structure and fair bit of geographic variation. They are found in the canopy and the litter but are rarely common. One exception that I know of: on BCI in 1990 horni was the second most common species in a plateau plot. One reason for their rarity may be their tendency to be uber-predators, feeding on other ants and often showing army-ant like behavior. One could likely have a good career studying this genus. Gnamptogenys males are common in the malaise traps. The males of this genus retain much of the architecture of the females.
Species are sorted by the head length classes. Jack Longino's Gnamptogenys pages are the source for most of the images and ID text.
Arboreal. Promesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum longitudinally striate; anterior margin of anterior apron of clypeus straight or shallowly concave, terminating laterally in sharply rectangular corners; HW greater than 0.73mm; petiolar node longitudinally costulate; meso-metapleural suture well impressed (this character separates regularis from the closely related horni, which occurs from Panama south).
Litter. AT4 strongly vaulted and much inflated; sculpture on AT4 uniformly granular and smooth; head width less than 1.0mm, length of mesosoma (WL) less than 1.6mm
Litter.
Litter. Promesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum longitudinally striate; anterior margin of narrow anterior apron of clypeus straight to distinctly concave in the middle, terminating laterally in rounded corners; anteroventral petiolar process with posterior lobe or square-cut corner, and with distinct fenestra; HW less than 0.9mm.
Litter. Promesonotal suture absent; scapes surpass margin of vertex when laid back; mandibles smoothly curving such that basal and apical margins form a continuous convexity; head yellowish to brown in color; mandibles dull yellow to brownish, usually lighter than cranial color, but not markedly contrasting with it; head and rest of body nearly concolorous; costulae often transverse across posterior face of propodeum; eyes relatively small (eye length = 0.25, width = 0.18, n=1 worker).
Litter. Promesonotal suture absent; scapes just barely reach, but do not distinctly surpass, margin of vertex when laid back; dorsal surfaces of mandibles striate on basal fourth or less, rest smooth and shining; head width across eyes less than 1.0mm.
Litter. Pronotum separated from remainder of mesosoma by a very distinct suture, completely breaking the sculpture; anteroventral process of petiole square-cut, with sharp posterior angle; metanotal suture not impressed, not breaking sculpture, much weaker than promesonotal suture; mesonotum and dorsal face of propodeum forming even convexity; scapes surpassing margin of vertex by less than length of first funicular segment; petiole posteriorly inclined, the anterior face joining the dorsal face through a broad convexity that contrasts with a sharper angle between the posterior and dorsal faces, but posterior face perpendicular, not concave.
Litter. Longino usually encounters this in "fresh treefalls". This species inhabits lowland rainforest, and is known from isolated workers, usually encountered in fresh treefalls.
Arboreal, nesting in live or dead stems. Pronotum separated from remainder of mesosoma by a very distinct suture, completely breaking the sculpture; anteroventral process of petiole a regularly tapering anterior tooth, not square-cut; petiolar node tilted posteriad in side view, the postero-dorsal angle sharply rounded and overhanging the posterior face; scapes surpassing margin of vertex by more than length of first funicular segment; scape length normally greater than 1.08mm; HL 1.281, HW 1.054, SL 1.213, WL 1.871 (n=1).
Litter--millipede specialists. Promesonotal suture very faintly impressed, not breaking sculpture; scapes surpass margin of vertex when laid back; mandibles distinctly triangular, basal margin flat; propodeum with small peg-like teeth; pronotal dorsum with longitudinal costulae that extend all the way to the anterior margin, only occasionally with one or two obscure transverse costulae at the junction of pronotum and occiput; posterior lobe of subpetiolar process low, much smaller than large anterior tooth.
Litter. Promesonotal suture very faintly impressed, not breaking sculpture; scapes surpass margin of vertex when laid back; mandibles distinctly triangular, basal margin flat; propodeum with small peg-like teeth; anterior pronotum covered by a broad band of transversely arching costulae; posterior lobe of subpetiolar process well developed, square-cut to acute, and subequal in size to anterior tooth.
Arboreal Pomesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum transversely striate; HL less than 1.5mm; when head is seen in perfect full-face view, vertex margin straight or feebly concave in the middle; propodeum unarmed.
Litter. Both promesonotal suture and metanotal suture distinct, completely breaking sculpture; anteroventral process of petiole square-cut, with sharp posterior angle.
Litter. Promesonotal suture faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum transversely striate; large, long-headed species, HL greater than 1.7mm; when head is seen in perfect full-face view, vertex margin evenly convex; blunt but distinct vestiges of paired teeth on the propodeum.
Litter. Specialized millipe Propodeum armed with a pair of long, slender spines, normally at least as long as the distance between the inner sides of their bases.
Litter.Promesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum longitudinally striate; anterior margin of narrow anterior apron of clypeus straight to distinctly concave in the middle, terminating laterally in rounded corners; anteroventral petiolar process more or less tapering anteriorly, lacking posterior lobe or square-cut corner, and lacking distinct fenestra; compound eye large, its greatest diameter greater than the maximum width of antennal scape; eye diameter/HW = 0.35; AT4 smooth and shining.
Nests in the canopy but will forage on the ground. Large, light orange species; HW without eyes greater than 2.0mm; sculpture finely striate.
Litter--millipede specialist. The large size and massive head make this species immediately recognizable in Costa Rica. The only other Costa Rican species of similar size is G. concinna. G. concinna is straw-colored; G. banksi is dark brown.
Last Updated: 20Dec2004