Trachymyrmex, Forel, 1893

Rabeling, Christian, Cover, Stefan P., Johnson, Robert A. & Mueller, And Ulrich G., 2007, A review of the North American species of the fungus-gardening ant genus Trachymyrmex (Hymenoptera: Formicidae), Zootaxa 1664, pp. 1-53 : 6

Key to the males of Trachymyrmex species occuring in the United States

Trachymyrmex nogalensis is not included in this key because the male of this species is unknown.

1 Ventrolateral pronotal tooth absent and dorsolateral pronotal tooth well-developed ( Figures 9 & 20 ) ...... 2

- Ventrolateral pronotal tooth often clearly present, if indistinct or absent then the dorsolateral pronotal tooth is also indistinct or absent ( Figures 2 , 4 , 7 , 14 , 16 & 18 )................................................................... 3

2 In dorsal view, dorsolateral pronotal tooth short, sharp, and triangular. Setae on first gastric tergite sparse, decumbent or appressed ( Figure 20 )................................................................................................. turrifex

- In dorsal view, dorsolateral pronotal tooth a needlelike spine. Setae on first gastric tergite short, moderately abundant, more or less recurved, and mostly erect ( Figure 9 ).......................................... jamaicensis

3 In dorsal view, dorsolateral pronotal tooth distinct, sometimes even forming a short spine ( Figures 2 , 7 & 16 )................................................................................................................................................................ 4

- In dorsal view, dorsolateral pronotal tooth very small or entirely absent, sometimes reduced to an angulate ridge, but not present as a tooth or spine ( Figures 4 , 14 & 18 ) ................................................................... 6

4 In lateral view, irregular rugulae present on all surfaces of pronotum; interrugal spaces granulate. Antennal scrobe granulate, with at least several transverse rugulae distributed over the anterior ¾ ( Figure 7 )...... .................................................................................................................................................... desertorum

- Pronotum generally lacking irregular rugulae, sometimes a few inconspicuous rugulae present near dorsolateral pronotal teeth. Antennal scrobe granulate, with 1–4 transverse rugulae near anterior margin or rugulae absent altogether .................................................................................................................................. 5

5 Surface of first gastric tergite bumpy due to the presence of numerous small tubercles; each tubercle bears a decumbent, recurved setae. Dorsoventral pronotal teeth large, narrowly triangular in dorsal view ( Figure 2 )................................................................................................................................................. arizonensis

- Surface of first gastric tergite finely granulate, lacking small tubercles, short, suberect somewhat recurved setae moderately abundant. Dorsoventral pronotal teeth short, broadly triangular in dorsal view ( Figure 16 )......................................................................................................................................... septentrionalis

6 Small species (HL 0.6–0.75; HW 0.6–0.75). In full-face view, preocular carinae weakening rapidly as it passes the posterior border of the eye and turns towards the midline, past the eye the carina not more prominent than adjacent rugulose sculpture on the posterior half of the head, rear border of scrobe sometimes indistinct ( Figure 14 )............................................................................................................ pomonae

- Larger species (HL 0.72–0.84; HW 0.75–0.87). In full face view, preocular carina remaining a distinctive vertical ridge as it passes the eye and turns towards the midline, past the eye the carina clearly more prominent than adjacent rugulose sculpture on the posterior half of the head, and remaining fully developed until reaching the midpoint of the posterior border of the scrobe ( Figures 4 & 18 ).................................... 6

7 In dorsal view, mesoscutum slightly broader than long, sculpture coarsely and irregularly rugulose and granulate, sometimes a faint longitudinal pattern is discernable ( Figure 4 ).................................. carinatus

- In dorsal view, mesoscutum about as long as broad, sculpture predominantly longitudinally rugulose, interrugal spaces finely granulose ( Figure 18 ) ................................................................................... smithi

Figures

FIGURE 2: Trachymyrmex arizonensis male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 2 mm, 1 mm and 2 mm in part (a), (b) and (c), respectively.

FIGURE 4: Trachymyrmex carinatus male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 1 mm, 0.5 mm and 1 mm in part (a), (b) and (c), respectively.

FIGURE 7: Trachymyrmex desertorum male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 2 mm, 1 mm and 1 mm in part (a), (b) and (c), respectively.

FIGURE 9: Trachymyrmex jamaicensis male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 1 mm, 0.5 mm and 0.5 mm in part (a), (b) and (c), respectively.

FIGURE 14: Trachymyrmex pomonae Paratype male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 1 mm, 0.5 mm and 1 mm in part (a), (b) and (c), respectively.

FIGURE 16: Trachymyrmex septentrionalis male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 2 mm, 1 mm and 1 mm in part (a), (b) and (c), respectively.

FIGURE 18: Trachymyrmex smithi male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 2 mm, 1 mm and 2 mm in part (a), (b) and (c), respectively.

FIGURE 20: Trachymyrmex turrifex male in (a) lateral, (b) full face and (c) dorsal view. Scale bar represents 2 mm, 1 mm and 2 mm in part (a), (b) and (c), respectively.