Eurhopalothrix

Longino, John T., 2013, A review of the Central American and Caribbean species of the ant genus Eurhopalothrix Brown and Kempf, 1961 (Hymenoptera, Formicidae), with a key to New World species, Zootaxa 3693 (2), pp. 101-151 : 107-110

Key to New World Eurhopalothrix (workers)

1. Face, dorsal mesosoma, and first gastral tergite covered with uniform ground pilosity of appressed spatulate setae, lacking differentiated erect or suberect setae projecting above ground pilosity; posterior face of propodeum with broad, rectangular lamella, not differentiated into acute propodeal spine ( Fig. 4 ); HW <0.5 ( Argentina)......................... E. bruchi

- Face, dorsal mesosoma, and first gastral tergite with thin, non-spatulate ground pilosity or, if with conspicuous spatulate ground pilosity, then accompanied by differentiated larger suberect to erect spatulate setae; posterior face of propodeum as above or with distinct acute propodeal spines; HW variable.................................................... 2

2. Face with well-defined transverse ridge that separates posterior and anterior portions of face, or clypeus with transverse ridge that separates small posterior triangular portion and larger, concave anterior portion ( Fig. 5 ).......................... 3

- Neither face nor clypeus with transverse ridge.............................................................. 5

3. Transverse ridge on face, not on clypeus................................................................... 4

- Transverse ridge on clypeus, not on face ( Guyana)................................................... E. clypeata

4. Face with 16 large spatulate setae ( Brazil).......................................................... E. depressa

- Face lacking spatulate setae ( Cuba).................................................................. E. cimu

5. Larger erect to suberect setae of face 12–20, distinctly differentiated from ground pilosity ( Fig. 6A ) or grading into and diffi- cult to distinguish from spatulate ground pilosity ( Fig. 6 B)..................................................... 6

- Larger erect setae at most 10; ground pilosity thin, distinctly differentiated from erect setae ( Fig. 6 C).................. 22

6. Propodeal spines in the form of broad, foliaceous crests that extend down posterior face of propodeum ( Fig. 7A ); face and dorsal surface of scapes covered with ground pilosity of conspicuous, broad appressed spatulate setae..................... 7

- Propodeal spines in form of acute triangles, with a narrow carina extending ventrally ( Fig. 7 B); dorsal surface of scapes with spatulate or narrower appressed setae, ground pilosity of face variable............................................ 8

7. HW <0.6, CI 89–97 (Central America)........................................................... E. pilulifera

- HW> 0.9, CI> 100 (southern Brazil)................................................................ E. lenkoi

8. HW <0.56; CI 96; ground pilosity conspicuous, spatulate; differentiated erect setae strongly spatulate, as broad as long; first gastral tergite with spatulate setae in double row of 4–5 pairs down the middle, flanked by 2 or 3 additional setae ( Trinidad)............................................................................................ E. alopeciosa

- HW> 0.55; CI> 95; other characters variable............................................................... 9

9. Eye large, about 9 ommatidia across long axis ( Fig. 8A); legs relatively long, hind tibia length about 0.6 HW; angle between anterior and dorsal faces of petiolar node obtuse; first gastral tergite with 4 pairs spatulate setae; ground pilosity of face uniformly distributed; masticatory margin of mandible with single tooth row ( Costa Rica)..................... E. megalops

- Eye small, 3–6 ommatidia across long axis ( Fig. 8 B); legs relatively short, hind tibia length about 0.4–0.5 HW; other characters variable......................................................................................... 10

10. Masticatory margin of mandible with double row of teeth, outer series of lower triangular teeth, inner row of 3–4 long, spini- form teeth ( Fig. 1 B, C); promesonotum rugose and puncta obliterated and frons with a distinct raised median carina...... 11

- Masticatory margin with single row of triangular teeth ( Fig. 1 A); promesonotum smooth (and sometimes shining) between dis- tinct puncta and frons without a distinct raised median carina.................................................. 15

11. Erect setae on face filiform to weakly clavate, not strongly spatulate ( Fig. 9A ) ( Cuba)....................... E. mabuya

- Erect setae on face strongly spatulate ( Fig. 9 B)............................................................. 12

12. Basal lobe of scape strongly developed, SLI> 15........................................................... 13

- Basal lobe of scape less developed, SLI <14............................................................... 14

13. Smaller, HW 0.57–0.66; basal lobe of scape more developed, SLI 21–25; color orange; posterior mesonotum lacking pronounced longitudinal keel ( Fig. 10A ) ( Honduras to Costa Rica).......................................... E. xibalba

- Larger, HW 0.69–0.83; basal lobe of scape less developed, SLI 15–21; color dark brown; posterior mesonotum with a pronounced, short longitudinal keel between the posteriormost pair of spatulate setae ( Fig. 10 B) ( Mexico, Guatemala)...................................................................................................... E. hunhau

14. Petiolar peduncle relatively thin in lateral view ( Fig. 11A ); head narrower ( Fig. 11 C), CI 97–99; size smaller, HW 0.71–0.74 ( Guadeloupe, Dominica).................................................................. E. guadeloupensis

- Petiolar peduncle thicker ( Fig. 11 B); head broader ( Fig. 11 D), CI 110–115; size larger, HW 0.83–0.94 (widespread). E. gravis 15. Promesonotal dorsum with 3 pairs of large, broadly spatulate setae; projecting setae of face prominent, spatulate, of uniform size, strongly differentiated from ground pilosity*; ground pilosity of face more or less uniformly distributed across frons, vertex lobes, and frontal carinae; first gastral tergite with 4 pairs spatulate setae, these of similar size and shape to those on face, distributed in two longitudinal rows...................................................................... 16 - Promesonotal dorsum with 0–2 pairs of filiform to spatulate setae, clearly differentiated from ground pilosity; projecting setae of face as above or differing in size and grading into ground pilosity; ground pilosity of face as above or variously restricted to symmetrical patches on each side of the midline; first gastral tergite with projecting setae variable.................... 17 * singleton from Costa Rica will fail at this couplet and may be a distinct species. See Comments under E. oscillum .

Figures

FIGURE 1. Eurhopalothrix mandibles, showing simple versus double tooth row. A. Dorsal face of mandible, E. oscillum. Teeth are numbered from 1 at the base to 11 at the apex. B. Dorsal face of mandible, E. floridana, with 10 teeth in outer row. C. Interior face of mandible, E. floridana. Lines point to inner tooth row. For species with an inner tooth row, note common condition in which outer tooth 1 is somewhat broadened, tooth 2 is long and sharp like inner teeth, teeth 3 – 6 are shorter and not as sharp, teeth 7 – 10 are slightly developed as an apical fork, with outer teeth long and inner teeth short.

FIGURE 4. Eurhopalothrix bruchi, face and lateral views (Paraguay, CASENT 0173970). Images from AntWeb (April Nobile).

FIGURE 5. A. Eurhopalothrix cimu, showing transverse facial arc. B. E. clypeata, showing clypeal carina (from Kempf and Brown, 1960).

FIGURE 6. A. Eurhopalothrix gravis, showing full complement of 18 specialized setae that are strongly differentiated from ground pilosity. B. E. semicapillum, showing full complement of 14 specialized setae that are not highly differentiated from ground pilosity. C. E. sepultura, showing full complement of 8 specialized setae.

FIGURE 7. A. Eurhopalothrix pilulifera, showing expanded infradental lamella. B. E. xibalba, showing narrow infradental lamella.

FIGURE 9. A. Eurhopalothrix mabuya, showing narrow setae on face. B. E. guadeloupensis, showing more spatulate setae on face.

FIGURE 10. A. Eurhopalothrix xibalba. B. E. hunhau, showing elevated keel on posterior mesonotum.

FIGURE 11. A. Eurhopalothrix guadeloupensis, lateral view of petiole. B. E. gravis, lateral view of petiole. C. E. guadeloupensis, face view. D. E. gravis, face view.