Pogonomyrmex bigbendensis

A rare species, it nests in the soil.

Identification
Key to North American Pogonomyrmex

Shows some similarities to Pogonomyrmex desertorum. It can be distinguished as the cephalic sculpture is almost absent and the head is mostly smooth and shining. (Mackay and Mackay 2002)

Distribution
Southern Texas and Chihuahua, Mexico.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Habitat
Creosotebush scrub.

Nomenclature

 *  bigbendensis. Pogonomyrmex (Pogonomyrmex) bigbendensis Francke & Merickel, 1982: 371, figs. 1, 2, 9, 12, 15 (w.) U.S.A.

Worker
Measurements of holotype followed, in parenthesis, by the ranges observed in paratypes: Head length 2.15 mm (2.05-2.35 mm), head width 2.45 mm (2.15-2.56 mm), cephalic index 113.95 (104.88-113.95), scape length 1.65 mm (1.45-1.75 mm), scape index 74.08 (74.08-75.49), maximum eye length 0.45 mm (0.40-0.48 mm), maximum eye width 0.35 mm (0.32-0.38 mm), ocular index 20.93 (19.51-20.93), Weber's length 2.65 mm (2.30-2.75 mm), petiolar node length 0.75 mm (0.65-0.80 mm), maximum width of petiolar node 0.60 mm (0.49-0.60 mm), postpetiolar length 0.65 mm (0.60-0.68 mm), postpetiole width 0.80 mm (0.65-0.80 mm).

Head broader than long; eye small and weakly convex, not extending beyond lateral margin of head. Mandible with seven subequal, blunt teeth. Apical margin of mandible broadly convex, basal margin straight. Base of antennal scape similar to P. apache Wheeler: with superior lobe considerably stronger than inferior lobe; basal flange very weak on superior lobe, developed as a strongly recurved lip on inferior lobe; longitudinal peripheral carina very strong, point absent. Lateral lobes of c1ypeus produced in front of antennal insertions, margin of c1ypeal lobe broadly and shallowly excised; frontal triangle deeply impressed. Median cephalic rugae longitudinal, parallel; extremely fine and closely set, producing a silky luster; interrugal spaces shiny; in lateral view rugae not forming whorls behind eye; posterior corner of head without rugae, smooth, strongly shiny.

Contour of thorax, petiole, and postpetiole, in lateral view. Thoracic rugae dense, fine, and shiny; transverse throughout. Epinotum unarmed; posterior epinotal declivity short, smooth. Dorsal portions of metasternal flanges fused, forming a single arcuate carina across posterior declivity of epinotum. Venter of petiolar peduncle with a few long, erect hairs in vicinity of peduncular process. Petiolar node flattened dorsally; with faint, transverse striae. Postpetiolar node dorsally with faint, transverse striae. Contour of petiolar and postpetiolar nodes, in dorsal view. First gastric segment broader than long. Body color uniformly reddish brown.