Pachycondyla masoala Rakotonirina, 2013

Rakotonirina, J. C. & B. L. Fisher, 2013, Revision of the Pachycondyla wasmannii - group (Hymenoptera: Formicidae) from the Malagasy region, Zootaxa 3609, pp. 101-141 : 123-124

Pachycondyla masoala Rakotonirina and Fisher, sp. n.

(Figures 7, 40-41, 52, 58)

Holotype worker: Toamasina, 6.3 km S Ambanizana, Andranobe, -15.6813, 49.958, 25 m, sifted litter, rainforest, 14 Nov 1993 (B.L. Fisher), collection code: BLF00886, specimen code: CASENT0317384 (CASC).

Paratypes: 8 workers with the same data as holotype but specimen coded: BLF0886(13)-2, BLF0886(48)-2; 13 Nov 1993 (B.L. Fisher), collection code: BLF0882, specimen codes: BLF0882(23)-2, BLF0882(2)-2, BLF0882(5)-1, BLF0882(32)-1, BLF0882(34)-1, BLF0882(42)-1 (BMNH, MHNG, MCZC, CASC, PBZT).

Worker diagnosis:

With head in full-face view, antennal scape not surpassing the posterior cephalic margin; dorsum of head and mesosoma not finely striate; dorsum of the body with erect slender hairs and pubescence; erect hairs and pubescence on dorsum of propodeum absent or reduced in number; petiole node anteroposteriorly flattened and tapered towards its apex, about twice as broad as long in dorsal view.

Worker measurements (n=10): HL: 1.69-1.83, HW: 1.54-1.67, CI: 91-93, SL: 1.22-1.31, SI: 76-82, PW: 1.16-1.31, WL: 2.04-2.26, NL: 0.69-0.81, NW: 1.02-1.14, NH: 1.18-1.29, HTL: 1.19-1.29, DNI: 135-159, LNI: 156-178.

Description:

Worker. Head somewhat elongate, sides almost straight behind level of eyes and narrowest in front, posterior margin noticeably medially excised. Compound eyes moderately large, but diameter smaller than maximum width of antennal scape. Scape relatively short, not surpassing posterior margin of head, leading edge rounded. Clypeus anteriorly truncate, and slightly notched medially. Mandibles triangular, the apical margins armed with seven to eight teeth and denticles. With mesosoma in lateral view, dorsal margin not forming a continuous convexity; propodeal dorsum and declivity separated by distinct angle; mesopleural suture visible. Propodeum slightly compressed laterally. In lateral view, node of petiole squeezed anteroposteriorly, anterior margin inclined posteriorly and posterior margin truncate, making dorsal margin shorter relative to ventral border. With petiole in dorsal view, node broader than long, posterior margin excavated medially. Head sculpture densely and finely reticulate–rugulose, superimposed with punctures which are larger in the dorsum behind level of eyes and become larger towards posterior margin.

Mandibles striate, interspersed with shallow piligerious punctures. Dorsum of pronotum and mesonotum densely reticulate-rugulose and covered with dense, coarse punctures; propodeum generally with fine reticulate punctures or rugulose. Sides of mesosoma densely and finely reticulate-rugulose. Petiole node laterally almost smooth and shining; small dorsal surface covered with closely spaced large and shallow punctures; adjacent punctures separated by sharp ridge. Third and fourth abdominal tergites with dense and large shallow punctures, which become sparse and irregularly scattered on the posterior half of the latter segment. Pilosity present on dorsum of body except on propodeum; pubescence reduced. Integument shiny, reddish brown or dark brown to black in color with lighter gaster and appendages.

Queen. Measurements (n=1): HL: 1.94, HW: 1.88, CI: 97, SL: 1.42, SI: 75, EL: 0.344, OI: 18, PW: 1.45, WL: 2.83, NL: 0.74, NW: 1.33, NH: 1.26, DNI: 180, LNI: 170.

Morphologically similar to worker except modifications of the queen caste, with head slightly broader, body size notably much larger.

Discussion:

Pachycondyla masoala can be confused with form 4 of P. cambouei because of the absence of erect hairs on the propodeal dorsum. However, a flattened petiole node, which shows a shorter dorsal margin in profile, separates it from P. cambouei , which has a thick petiole node.

Distribution and biology:

Pachycondyla masoala is only known from the lower elevations of humid forests in northeastern Madagascar (Fig. 58) around the PN Masoala, and in the Makirovana forest near Sambava. One nest was found under a dense layer of roots and litter on a rock, but the species generally forages on the forest floor and through leaf litter.

Other material examined:

Antsiranana: 14 km W Cap Est, Ambato, -15.29128, 50.33803, 150 m, secondary rainforest (Alpert et al.) (MCZC); Makirovana Forest, -14.17066, 49.95409, 415 m, rainforest (B.L. Fisher et al.) (CASC); Makirovana Forest: -14.1604, 49.9522, 550 m, -14.1707, 49.9541, 415 m, 225 m, rainforest (B.L. Fisher et al.) (CASC); Toamasina: 5.3 km SSE Ambanizana, Andranobe, -15.66667, 49.96667, 425 m, rainforest (B.L. Fisher) (CASC); 6.3 km S Ambanizana, Andranobe, -15.6813, 49.958, 25 m, rainforest (B.L. Fisher) (CASC); Nosy Mangabe, 15.5, 49.76667, 150-300 m, rainforest (P.S. Ward) (PSWC).