Key to Polyrhachis Cyrtomyrma of Borneo

This worker key is based on Kohout 2006, 2007.

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• Polyrhachis
• Cyrtomyrma
• Ants of Borneo

1

• Pronotal shoulders produced into distinct teeth . . . . . 2

• Pronotal shoulders without distinct teeth, narrowly or broadly rounded or bluntly angular . . . . . 6

2

return to couplet #1

• Head, mesosoma, petiole and gaster finely shagreened, jet-black . . . . . 3

• Head, mesosoma and petiole distinctly reticulate-punctate, opaque, distinctly blue or with bluish sheen . . . . . 4

3

return to couplet #2

• Mesosoma in profile strongly convex anteriorly; mesonotum, propodeum and declivity descending posteriorly in an almost straight line; petiolar spines reduced to obtuse teeth . . . . . Polyrhachis laevissima

• Mesosoma in profile moderately convex; mesonotum and propodeum descending posteriorly in weakly convex line before abruptly sloping into steep declivity; petiole with elongate lateral spines . . . . . Polyrhachis sulang

4

return to couplet #2

• Propodeum armed with pair of short spines; petiole with pair of elongated lateral spines, dorsal pair lacking . . . . . Polyrhachis bruehli

• Propodeal dorsum unarmed; petiole with pair of dorsal blunt teeth and pair of distinctly longer lateral spines . . . . . 5

5

return to couplet #4

• Anterior clypeal margin with central, blunt, projecting tooth . . . . . Polyrhachis achterbergi

• Anterior clypeal margin deeply emarginate medially . . . . . Polyrhachis widodoi

6

• Larger species (HL > 1. 65); petiole with sides more-or-less parallel, spines reduced to minute denticles . . . . . Polyrhachis danum

• Smaller species (11 L < 1. 65); petiole with sides diverging, spines acute . . . . . 7

7

return to couplet #6

• Pronotal shoulders broadly rounded; lateral petiolar spines lip to four times as long as their basal width . . . . . Polyrhachis acuminata

• Pronotal shoulders narrowly rounded or subangular; lateral petiolar spines at most twicc as long as their basal width . . . . . 8

8

return to couplet #7

• Propodeal declivity very steep, virtually vertical; lateral petiolar spines distinctly longer than dorsal pair; legs dark reddish-brown . . . . . Polyrhachis lepida

• Propodeal declivity oblique; petiolar spines subequal or lateral pair shorter than dorsal pair; legs mostly orange or light reddish-brown . . . . . Polyrhachis rastellata

References

• Kohout, R.J. 2007d. A new species of the subgenus Polyrhachis (Cyrtomyrma) Forel from Borneo. Australian Entomologist 34: 115-118.
• Kohout, R. J. 2006b. Review of Polyrhachis (Cyrtomyrma) Forel (Hymenoptera: Formicidae: Formicinae) of Australia, Borneo, New Guinea and the Solomon Islands with descriptions of new species. Memoirs of the Queensland Museum. 52:87-146.