Pachycondyla sikorae

Rakotonirina, J. C. & Fisher, B. L., 2013, Revision of the Pachycondyla sikorae species-group (Hymenoptera: Formicidae) in Madagascar, Zootaxa 3683 (4), pp. 447-485 : 449-451

Diagnosis of workers and queens of P. sikorae species-group

In the Malagasy region, the P. sikorae-group is most similar to species in the recently revised P. wasmannii-group (by Rakotonirina & Fisher 2013). These two groups share many characters listed below but the sikorae-group can be distinguished by the presence of a lateral circular pit at the base of the mandibles (Fig. 1). In the field, verification of the circular pit in the smaller species may be difficult, but workers of the P. sikorae-group can be recognized by their slender body, shiny integument, and their immediate moving reaction when their nests are disturbed. Conversely, those of the P. wasmannii-group can be identified by their robust body, matte integument, and their ability to simulate death when disturbed.

1. Mandible subtriangular, masticatory margin with 9-12 teeth and denticles. 2. Mandible with dorsolateral pit or fovea near the base; lateral sulcus present, running from the base to the apex. 3. Palp formula 2, 2. 4. Frontal lobes with an anteriorly broadly rounded outer margin which is posteriorly and laterally compressed to form a narrow surface at about the level of the eyes. 5. Anteromedian margin of clypeus straight and medially notched in P. gorogota , P. haratsingy , P. ivolo , P. maeva , P. mialy , P. nosy , P. sikorae or triangular or broadly rounded in P. agnivo , P. antsiraka , P. daraina , P. rovana , P. tahary , P. vohitravo and P. zoro. 6. Antenna with 12 segments, the funiculus gradually increasing in width towards the apex and without a distinct club. 7. Compound eyes variable in size, rarely larger than the maximum diameter of antennal scape or greater ( P. sikorae , P. agnivo) and most often smaller than approximately half of the maximum diameter of antennal scape; located roughly at the midline of the head when viewed in profile. 8. Apical portion of hind tibiae with two spurs, a large pectinate spur and an anterior spur that is much smaller and simple. 9. Pretarsal claws simple. 10. Metanotal groove strongly impressed in P. gorogota , P. maeva , and P. sikorae to feebly distinct in P. haratsingy and P. nosy , or absent in other remaining species. 11. Mesopleural sulcus usually indistinct, present as three to fourbroad, discontinuous grooves or as a single narrow sulcus. 12. Posterolateral margin of propodeum simply rounded or marginate ( P. haratsingy , P. rovana , P. sikorae ), bordered with lamellae ( P. gorogota , P. maeva , P. daraina , P. zoro) or covered with a series of sharp teeth or denticles ( P. antsiraka , P. tahary , P. vohitravo). 13. Propodeal spiracle slit-like. 14. Metapleural gland opening just above the posteroventral angle of mesosoma. 15. Petiole node usually thick, very rarely a flattened scale with slight posteromedian notch ( P. gorogota , P. maeva). 16. Helcium approximately at the anteroventral angle of the first gastral segment (fourth abdominal segment). 17. First and second gastral segments with distinct constriction. 18. Stridulitrum absent. 19. Sting well developed. 20. Queen comparatively similar to worker, but with the following distinctive features: broader head, presence of ocelli, eye diameter greater than the greatest width of antennal scape; mesopleuron divided into an episternum and katepisternum by a transverse sulcus; the mesosomal flight sclerites fully developed; petiole node more or less flattened anteroposteriorly; moderately larger body size with usually more voluminous gaster and denser and more elongate pubescence.

The worker caste of the P. sikorae-group in Madagascar can be identified by the combination of the following characters: presence of a pit on the lateral portion of the base of the mandibles (Fig. 1); the shape of the anterior clypeal margin either approximately straight with slight median notch (Fig. 2) or projecting into triangular lobe (Fig. 3); the slit-shaped opening of propodeal spiracles; metanotal groove either present or absent; hind legs with two tibial spurs, of which one is large and pectinate and the other smaller and simple; posterior margin of propodeum simple, lamellate or infrequently with a series of sharp teeth; thick petiolar node whose posterodorsal angle has no long spines and whose posterolateral margins occasionally have a series of sharp teeth or tubercles (Fig. 19); the frontal lobes are broadly rounded. Workers of the P. sikorae-group are superficially similar to those of the P. wasmannii-group , but the former have a lateral circular pit or fovea near the base of their mandibles, which is absent in the P. wasmannii-group .

The shape of the anterior margin of the clypeus allows the division of the P. sikorae-group into two species complexes. First, the sikorae complex, which includes seven species, has a broadly transverse and roughly straight anterior clypeal margin, with slight median notch (Fig. 2); second the vohitravo complex, which also contains seven species, is characterized by a medially convex or bluntly angulate anterior margin of clypeus (Fig. 3).

Synopsis of the taxonomic history of the P. sikorae species-group