Pachycondyla agnivo Rakotonirina and Fisher

Rakotonirina, J. C. & Fisher, B. L., 2013, Revision of the Pachycondyla sikorae species-group (Hymenoptera: Formicidae) in Madagascar, Zootaxa 3683 (4), pp. 447-485 : 458-459

Pachycondyla agnivo Rakotonirina and Fisher , sp. n. (Figures 16, 28, 29, 30, 70)

Holotype worker: Madagascar, Toamasina, FC Andriantantely, -18.695, 48.8133, 530 m, sifted litter, rainforest, 7-10 Dec 1998 (H.J. Ratsirarson), collection code: HJR122, specimen code: CASENT0317589 (CASC).

WORKER. Diagnosis: Anteromedian margin of clypeus broadly convex; posterolateral margins of propodeum and petiolar node smooth, without sharp teeth or tubercles; anterior surface of first gastral segment concave, forming a shallow impression to lodge the posterior surface of petiole.

Measurements (3 specimens): HW: 1.14-1.15, HL: 1.36-1.40, CI: 82-84, SL: 1.01-1.03, SI: 88-90, PW: 1.01-1.03, WL: 1.96-2.04, NH: 0.87-0.89, NL: 0.63-0.68, NW: 0.94-0.96, DNI: 143-150, LNI: 129-138.

Description: In full face-view, head broader posteriorly; sides slightly convex; posterior margin feebly concave. Dorsum of head reticulate-punctate anteriorly and densely punctate behind from about the posterior third. Eyes large, maximum diameter nearly the same as the greatest width of antennal scape. Scape barely reaching posterior cephalic margin. Anteromedian clypeal margin convex. Mandibles sparsely punctate, the space between punctures smooth and shiny; masticatory margin armed with 12 teeth or denticles.

With mesosoma in dorsal view, metanotal groove obsolete; in profile, mesopleural suture absent or indistinct; posterior magin of propodeum without a series of sharp teeth or tubercles; junction of lateral propodeal surface and declivity angulate, angles fairly emarginate. Dorsum of mesosoma with punctate sculpture. Petiole nodiform, anterodorsal angle faintly overhanging anterior margin in lateral view; subpetiolar process consisting of convex anterior face and broadly subquadrate posterior margin; in dorsal view node slightly broader than long, lateral border roughly convex and converging in a rounded line to the more or less straight anterior face; posterior margin medially broadly convex; dorsum of node sparsely punctate.

Anterior face of first gastral segment with shallow cavity, which is deeper near the insertion of petiole and becomes superficial towards the anterodorsal angle. With gaster in ventral view, anterior half of first gastral sternite with impressions on both sides of helcium; in profile anteroventral portion rounded and anteriorly projecting as hooklike process (the prora). Dorsum of first two gastral tergites smooth between piligerous punctures.

Dorsum of head and body covered with erect hairs; pubescence quite abundant on head dorsum and scarce or absent on the rest of body dorsum. Body color black with bluish reflection; appendages and tip of gaster brown.

Queen: unknown.

Discussion: Pachycondyla agnivo can be recognized easily by the medially convex anterior margin of its clypeus and the presence of a shallow impression on the anterior face of its first gastral tergite. No striking morphological variation is observed in this species despite the great distance between collection localities in the south and the center of Madagascar.

The shallow impression on the anterior face of the first gastral segment matches the shape of the posterior section of the petiolar node, suggesting this hollow plays a role in lodging the posterior face of the node.

Distribution and biology: Pachycondyla agnivo is an endemic species found in mid-elevation areas of eastern Madagascar. In addition to the type locality, the species occurs in the PN Mantadia in the central east and in the PN Andohahela in the southernmost portion of the island. It was collected by sampling leaf litter in the central east of Madagascar and was only recorded once from a pitfall trap in Andohahela.

Additional material examined: Province Toamasina: PN Mantadia, 895 m, rainforest (H.J. Ratsirarson) (CASC); Province Toliara: PN Andohahela, Col du Sedro, 3.8 km 113° ESE Mahamavo, 37.6 km 341° NNW Tolagnaro, 900 m, montane rainforest (Fisher-Griswold Arthropod Team) (CASC).