Key to Pristomyrmex of the Philippines

This worker key, and accompying text, is based on Zettel, H. 2006. On the ants of the Philippine Islands: 1. The genus Pristomyrmex Mayr, 1866. Myrmecologische Nachrichten 8:59-68.

In general, intraspecific variability appears to be very low in species of Pristomyrmex, which makes identification relatively simple compared to many other myrmicine genera. This key does not include Pristomyrmex cebuensis, described by Zettel in 2007.

Species diversity and regional endemism in the Philippines

At present, 55 species of Pristomyrmex are described (Wang 2003, and this paper). Seventeen species are recorded from the Philippines (= 30.9 % of world fauna). Of these seventeen species, nine species seem to be endemic to the Philippines (= 16.4 % or one sixth of world fauna). The question, whether species are regionally endemic or not, needs to be answered with caution due to the relatively small number of collections.

Most species records are from Greater Mindanao (10 species), Greater Luzon (7 species), and Greater Negros-Panay (5 species), probably because of the more intensive collecting activities and more suitable habitats on the larger islands.

Key to Workers

1

Pronotal spines not at all developed . . . . . 2

Pronotal spines developed, short and triangular or long . . . . . 6

2

return to couplet #1

Dorsal surface of head and alitrunk rugoreticulate . . . . . 3

Dorsal surface of head and alitrunk punctate or foveolate . . . . . 4

3

return to couplet #2

Femora and tibiae reddish or brown; basal margin of mandible with or without inconspicuous tooth . . . . . Pristomyrmex punctatus

Head of Pristomyrmex punctatus worker

Profile of Pristomyrmex punctatus worker

Femora and tibiae yellow; basal margin of mandible with a broad tooth . . . . . Pristomyrmex pulcher

Head of Pristomyrmex pulcher worker

Profile of Pristomyrmex pulcher worker

4

return to couplet #2

Masticatory margin of mandible without diastema; petiolar node in profile longer than high and distinct from peduncle. . . . . . Pristomyrmex picteti

Head of Pristomyrmex picteti worker

Profile of Pristomyrmex picteti worker

Masticatory margin of mandible with diastema; petiolar node in profile higher than long or not clearly separated from peduncle . . . . . 5

5

return to couplet #4

Frontal carinae short, not extending to level of posterior margin of eye; masticatory margin of mandible with diastema . . . . . Pristomyrmex divisus

Head of Pristomyrmex divisus worker

Profile of Pristomyrmex divisus worker

Frontal carina long, extending to level of posterior margin of eye; masticatory margin of mandible without diastema . . . . . Pristomyrmex simplex

Head of Pristomyrmex simplex worker

Profile of Pristomyrmex simplex worker

6

return to couplet #1

Dorsal surface of head (and usually also alitrunk) rugoreticulate . . . . . 7

Dorsal surface of head and alitrunk smooth or punctate . . . . . 11

7

return to couplet #6

First gastral tergite with numerous, evenly distributed erect or suberect setae . . . . . Pristomyrmex hirsutus

First gastral tergite without erect or suberect setae . . . . . 8

8

return to couplet #7

Ventral surface of clypeus without central tooth . . . . . 9

Ventral surface of slypeus with a central tooth . . . . . 10

9

return to couplet #8

Pronotal spines very long (at least 0.36 mm), usually longer than distance between their bases . . . . . Pristomyrmex bicolor

Head of Pristomyrmex bicolor worker

Profile of Pristomyrmex bicolor worker

Pronotal spines short (shorter than 0.30 mm), much shorter than distance between their bases . . . . . Pristomyrmex costatus

Head of Pristomyrmex costatus worker

Profile of Pristomyrmex costatus worker

10

return to couplet #8

Pronotal spines very short (0.06-0.12 mm), at most as long as propodeal spines . . . . . Pristomyrmex brevispinosus

Head of Pristomyrmex brevispinosus worker

Profile of Pristomyrmex brevispinosus worker

Pronotal spines relatively long (0.15-0.17 mm), distinctly longer than propodeal spines . . . . . Pristomyrmex rugosus

Head and profile of Pristomyrmex rugosus worker

11

return to couplet #6

Pronotal spines triangular, short . . . . . 12

Pronotal spines long . . . . . 15

12

return to couplet #11

Dorsum of head with large foveolate punctures . . . . . Pristomyrmex quadridens

Head of Pristomyrmex quadridens worker

Profile of Pristomyrmex quadridens worker

Dorsum of head with relatively fine punctures . . . . . 13

13

return to couplet #12

Petiolar node in profile without distinct anterior face or separated from upper surface of peduncle; head width 0.98-1.04 mm . . . . . Pristomyrmex flatus

Head of Pristomyrmex flatus worker

Profile of Pristomyrmex flatus worker

Petiolar node in profile with anterior face distinctly separated from upper surface of peduncle; head width 0.77-0.94 mm . . . . . 14

14

return to couplet #13

Pronotal spines distinctly shorter than propodeal spines; antennal scrobes present, laterally delimited by ridge caudally at least to level of centre of eye . . . . . Pristomyrmex distinguendus

Head and profile of Pristomyrmex distinguendus worker

Pronotal spines subequal in length to propodeal spines; antennal scrobes absent, laterally not delimited by ridge . . . . . Pristomyrmex collinus

Head of Pristomyrmex collinus worker

Profile of Pristomyrmex collinus worker

15

return to couplet #11

Clypeus with median carina . . . . . Pristomyrmex curvulus

Head of Pristomyrmex curvulus worker

Profile of Pristomyrmex curvulus worker

Clypeus without median carina . . . . . 16

16

return to couplet #15

Petiolar node in profile lacking distinct anterior surface separated from dorsal surface of peduncle; propodeal spines relatively long (PSL2 0.18-0.26) . . . . . Pristomyrmex longispinus

Head of Pristomyrmex longispinus worker

Profile of Pristomyrmex longispinus worker

Petiolar node in profile with distinct anterior surface separated from dorsal surface of peduncle; propodeal spines relatively short (PSL2 0.09-0.13) . . . . . Pristomyrmex schoedli

Head and profile of Pristomyrmex schoedli worker