Key to Pristomyrmex workers

This worker key is based on: Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-54

Note: Pristomyrmex fuscipennis and Pristomyrmex reticulatus, whose worker castes are presently unknown, are not included in the key.

1

 * Dorsum of alitrunk in profile not arched, with mesonotum much higher than propodeal dorsum, that is, a vertical cliff present between mesonotum and propodeal dorsum. Antennal scrobes well developed and deep. Basal margin of mandible with a strong tooth adjacent to the basal tooth of masticatory margin so that five teeth are set close together. Base of antennal scape without a circling lamella (profundus group; Asia: Sabah) . . . . . Pristomyrmex profundus


 * Dorsum of alitrunk in profile, excluding armaments, more or less arched-shaped, never showing a vertical cliff between mesonotum and propodeal dorsum. Antennal scrobes absent or shallow. Tooth on basal margin of mandible either absent or present; if present, it is on about midway, not adjacent to the basal tooth of masticatory margin. Base of antennal scape with a circling lamella . . . . . 2

2

 * Masticatory margin of mandible with four teeth; the third tooth, counting from the apex, smallest, distinctly smaller than tl1e basal one; diastema absent between the preapical and the third tooth (levigatus group; Asia, Australia) . . . . . 3


 * Masticatory margin of mandible with three to five teeth ; if four teeth present, then the third tooth, counting from the apex, similar in size to the basal one; diastema either present or indistinct between the preapical and the third tooth . . . . . 14

3

 * Propodeum unarmed. Petiole node in profile wedge-shaped (Asia: Papua New Guinea) . . . . . Pristomyrmex inermis


 * Propodeum armed with a pair of teeth or spines. Petiole node in profile nodiform, not wedge-shaped . . . . . 4

4

 * Pronotum armed with a pair of teeth (Asia and Pacific Is.: Papua New Guinea; Indonesia; Pohnpei Is.; Palau Is.; Yap 1.; Tonga Is.; Wallis Is.; found rarely in N. Queensland, Australia)  . . . . . Pristomyrmex minusculus


 * Pronotum unarmed . . . . . 5

5

 * Postpetiole in profile with an arched anterior face and a steeply sloping posterior face and the apex of postpetiole pointing posterior-upwardly; in dorsal view, postpetiole usually longer than broad, very rarely about as long as broad. Petiole node with a single evenly blunt-rounded apex. Head broader; HW mostly > 1.00 (Asia: Papua New Guinea) . . . . . Pristomyrmex lucidus


 * Postpetiole in profile with a somewhat evenly convex dorsum, lacking an abruptly steep posterior face and in dorsal view broader than long. Petiole node in profile with a distinct anterodorsal angle (Head narrower; HW < 1.00 . . . . . 6

6

 * Dorsum of petiole node late rally compressed and in dorsal view distinctly longer than broad (Asia: New Guinea) . . . . . Pristomyrmex longus


 * Dorsum of petiole node not laterally compressed and in dorsal view about as broad as or broader than long, not longer than broad . . . . . 7

7

 * Dorsum of alitrunk unsculptured, smooth and shining. Dorsum of head between frontal carinae usually smooth and shining, except for a few punctures bordering frontal carinae . . . . . 8


 * Dorsum of alitrunk with some scattered foveolate punctures. Dorsum of head between frontal carinae with scattered foveolate punctures or foveolate-reticulate sculpture . . . . . 12

8

 * Eyes smaller, with two to three ommatidia in the longest row (Asia: New Guinea) . . . . . Pristomyrmex boltoni


 * Eyes larger, usually with five to seven ommatidia in the longest row . . . . . 9

9

 * Larger species, with HW 0.90-0.96 and HL 0.90- 0.90 (Pacific Is.: Pohnpei I.) . . . . . Pristomyrmex largus


 * Smaller species; HW < 0.80, HL < 0.80 . . . . . 10

10

 * Ventral surface of petiole with a long pinlike process (Pacific Is.: New Heblides) . . . . . Pristomyrmex acerosus


 * Ventral surface of petiole without a long pinlike process . . . . . 11

11

 * Each side of petiole with a longitudinal carina that separates the tergite from the sternites. Basal margin of mandible with a short, broad tooth (Asia and Pacific Is.: Papua New Guinea, Solomon Is., Nama Is., New Britain Is.) . . . . . Pristomyrmex levigatus


 * Sides of petiole unsculptured and smooth, lacking a longitudinal carina. Basal margin of mandible with a prominent tooth (Pacific Is.: Fiji ) . . . . . Pristomyrmex mandibularis

12

 * Entire first gastral tergite evenly clothed with numerous erect or suberect hairs (Pacific Is.: Solomon Is.) . . . . . Pristomyrmex obesus


 * Only a few hairs present usually near the base of the first gastral tergite . . . . . 13

13

 * Dorsum of head, except for the scrobes, with foveolate-reticulate sculpture; punctures often aligned so that it seems that several longitudinal rugae appear between frontal carinae. Eyes smaller, EL = 0.06-0.08, with three to four ommatidia in the longest row (Asia: Papua New Guinea) . . . . . Pristomyrmex coggii


 * Dorsum of head between frontal carinae with some scattered foveolate punctures; space between foveolae smooth. Eyes large r, EL = 0.09-0.12, usually containing five (rarely four) ommatidia in the longest row (Asia: Papua New Guinea) . . . . . Pristomyrmex simplex

14

 * Masticatory margin of mandible with four teeth, lacking a distinct diastema. Lamella, circling the base of antennal scape, with a broad and deep notch on the center of the dorsal surface. Petiole node in profile longer than high (umbripennis group; Asia) . . . . . 15


 * Masticatory margin of mandible with three to five teeth; usually with a distinct diastema; if (very rarely) diastema indistinct, masticatory margin with five teeth. Lamella, circling the base of antennal scape, entire, without a notch on the center of the dorsal surface. Petiole node in profile usually higher than long . . . . . 17

15

 * Eyes larger, usually consisting of 20 or more ommatidia, containing six to seven ommatidia in the longest row. Propodeum with a pair of toothlike armaments that are shorter than the distance between their bases. About one-third of antennal scape usually laterally compressed near the base (Asia: Papua New Guinea, Indonesia) . . . . . Pristomyrmex umbripennis


 * Eyes smaller, generally consisting of less than 10 ommatidia, with three to four ommatidia in the longest row. Propodeum with a pair of spines that are longer than the distance between their bases. Antennal scape not laterally compressed near the base . . . . . 16

16

 * Propodeal spines longer and strongly upcurved at their apices. Larger species with HL 1.42-1.54, HW 1.42- 1.58 (Asia: W. Malaysia, Borneo) . . . . . Pristomyrmex pollux


 * Propodeal spines shorter and not strongly upcurved at their apices. Smaller species with HL 1.04-1.36, HW 1.02-1.40 (Asia: Papua New Guinea, Indonesia, Singapore, Malaya, Sabah, Brunei, Philippines) . . . . . Pristomyrmex picteti

17

 * Pronotum unarmed. Eyes larger, usually containing seven or more (very rarely six) ommatidia in the longest row. Dorsal surfaces of head and alitrunk with well developed rugoreticulum or many foveolate punctures (punctatus group; Asia, Africa) . . . . . 18


 * Pronotum usually with a pair of teeth or spines; if (very rarely) pronotal teeth or spines absent, then either eyes smaller, with two to five ommatidia in the longest row, or dorsal surfaces of alitrunk and head between frontal carinae unsculptured and smooth . . . . . 22

18

 * Dorsum of alitrunk with well developed coarse reticulum. Propodeum armed with a pair of long spines. Antennal scapes longer, usually > 0.78; one-sixth to one-fifth of the length of the scapes projecting beyond the occipital margin. Palp formula 5,3 . . . . . 19


 * Dorsum of alitrunk with scattered foveolate punctures. Propodeum armed with a pair of short spines. Antennal scapes shorter, with the length 0.54-0.60, only close to the occipital margin. Palp formula 4,3 (South Africa) . . . . . Pristomyrmex fossulatus

19

 * Lateral portions of clypeus, in front of antennal fossae, developed and not reduced to narrow margins. Anterior clypeal margin lacking distinct denticles. Median portion of clypeus not flat . . . . . 20


 * Lateral portions of clypeus reduced to a narrow margin in front of the antennal fossae. Anterior clypeal margin with five to seven denticles. Median portion of clypeus more or less flat . . . . . 21