Malagidris alperti Bolton & Fisher

Bolton, Barry & Fisher, Brian, 2014, The Madagascan endemic myrmicine ants related to Eutetramorium (Hymenoptera: Formicidae): taxonomy of the genera Eutetramorium Emery, Malagidris nom. n., Myrmisaraka gen. n., Royidris gen. n., and Vitsika gen. n .., Zootaxa 3791 (1), pp. 1-99 : 19-21

Malagidris alperti Bolton & Fisher sp. n.

(Figs 10-12, Map 126)

WORKER (holotype in parentheses). TL 5.8-6.5 (5.8), HL 1.22-1.34 (1.22), HW 0.82-0.96 (0.82), CI 65-72 (67), SL 1.45-1.61 (1.52), SI 160-192 (185), PW 0.68-0.82 (0.69), WL 1.80-1.90 (1.82) (18 measured).

Mandible with 10-12 teeth and denticles in total, finely longitudinally costulate. Median clypeal seta stout, in dorsal view not arising from a tubercle at the midpoint of the anterior margin. In profile the clypeal outline is more or less evenly convex from apex to base, without an elevated false anterior margin that is subtended by a vertical or reflexed section of the clypeus that descends to the true anterior margin. In profile the median clypeal seta arises from just above the anterior margin of the clypeus. Scapes long (SI 160 or more), with minute pubescence but lacking standing setae. Club segments of funiculus long and slender, distinctly longer than broad. EL 0.22-0.24 (EL/HW 0.25-0.29). With head in profile the dorsal outline above and behind the eye is obviously concave to distinctly indented; posteriorly the outline of the concavity rises to the highest point of the vertex. With head in full-face view sides behind the eyes elongate, shallowly convex and weakly convergent posteriorly, passing into the posterior margin through a short angle; posterior margin shallowly concave and the occipital carina raised into a translucent cuticular flange that is widest medially. Dorsum of head predominantly longitudinally rugose, with occasional anastomoses; posteriorly the number of anastomoses increases. Spaces between the rugae reticulate-punctulate, usually more strongly so on the anterior half. Ventral surface of head with superficial rugulae. Dorsum of mesosoma sharply rugose, the strongest rugae transverse on pronotal disc and with some reticulation; spaces between the rugae mostly smooth, not reticulate-punctulate. In dorsal view the lower sides of the pronotum are flared outward above the coxal articulations, so that the maximum pronotal width, across the flared portion, is greater than across the humeri. Propodeal spines long in profile (0.48-0.58); propodeal declivity unsculptured. Side of mesosoma rugose to reticulate-rugulose, but not as strongly sculptured as the dorsum; sculpture partially to mostly effaced on mesopleuron and metapleuron. Metafemur long and slender, MfL 1.86-2.00 (MfL/HW

1.96-2.41, MfL/MfH 6.30-8.30). Peduncle of petiole long and slender, downcurved in profile and with a small, dentiform anteroventral process. Subpetiolar process not followed by a cuticular crest along the mid-ventral surface of the peduncle. Petiole node in profile narrowly conical, vertical to slightly inclined anteriorly; acute apically. In posterior view the sides of the petiole node converge in their upper halves, the short apical margin is narrowly rounded to flattened. Petiole node with faint superficial punctulate sculpture, almost effaced in some. Postpetiole in profile convex dorsally, about 1.20-1.48 times longer than high; in dorsal view distinctly longer than broad; maximum dorsal width of postpetiole 0.37-0.46, very slightly less than its height. Dorsum of postpetiole node finely punctulate and with a few weak superficial rugulae. Base of first gastral tergite at most with superficial basigastral costulae, sometimes entirely effaced; tergite otherwise unsculptured.

Pilosity: with head in full-face view the side, both in front of and behind the eye, without projecting setae; with head in profile the dorsum behind the highest point with 2-3 pairs of setae that are inclined anteriorly, followed by a transverse row of 4 setae closest to the posterior margin (rarely this row is reduced to a widely separated pair, or is absent); pronotal dorsum without setae; mesonotum anteriorly with 1 pair, without setae at the metanotal groove; propodeal dorsum lacks setae; ventral surface of metafemur lacks setae; petiole node with a pair of setae on its posterior face; postpetiole with 1 pair dorsally and with a transverse row of 4 posteriorly; gaster with numerous short simple setae. Full adult colour yellow to light orange-yellow.

QUEEN (gyne). Ergatoid (e.g. CASENT0248384). TL 6.8, HL 1.28, HW 0.93-0.97, CI 73-76, SL 1.35-1.38, SI 142-145, WL 1.72-1.74, MfL 1.70-1.72, MfL/HW 1.77-1.83, MfL/MfH 7.17-7.53. EL 0.24-0.25 (EL/HW 0.26) (2 measured). Propodeal spine length ca 0.46, but the spines stouter than in the worker. Postpetiole length 0.60, width 0.58-0.60, height 0.60-0.63. Maximum width of first gastral tergite 1.50-1.60 (as opposed to <1.30 in worker). Most dimensions are within the worker ranges, but the scape is relatively shorter, and the metafemur is both absolutely and relatively shorter. In general the ergatoid matches the worker description, but the pronotal sculpture is more sharply reticulate-rugose, and the humeral angles are more pronounced. Pilosity as worker but head without the posterior transverse row (this may have been abraded away in the single specimen available). Ocelli absent or at most with a pit-like vestige of the median ocellus among the cephalic sculpture.

MALE. Mandible with 8-9 sharp teeth. CI 73-74, SI 45-48, MfL ca 1.25 (2 measured). First funicular segment of antenna less than 0.50 times the length of the second segment. EL/HW 0.45-0.46. With head in profile the dorsal outline behind the posterior ocelli slopes down to the occipital carina, the surface not vertical immediately behind the ocelli. With mesosoma in dorsal view the pronotum forms a visible anterior arc in front of the mesoscutum. Notauli absent. Peduncle of petiole with spiracles borne on low prominences, in dorsal view the distance across them slightly less than the maximum width of the node. Postpetiole in dorsal view slender, I.89-1.92 x longer than broad.

Three males are known, all from the Andrakaraka series noted below (CASC). In all of them the metatibiae are strangely deformed, and in most there is some degree of deformity to the femora, tibiae and basitarsi of the middle and hind legs. It is not considered that this is a normal morphological character, but rather is the result of a genetic aberration or the result of parasitoid attack in a pre-imaginal stage. The deformities are not seen in any workers or ergatoids from the same series.

Holotype worker, Madagascar: 5 km. SW Antalaha [Prov. Antsiranana], 50 m., 14°56 ’17” S, 50°15 ’42” E, 27.ii.1991. Secondary forest, foraging on ground. 4470w. Aphaenogaster sp. 1, det. Alpert, 1994. DNA. CASENT0170928 (G.D. Alpert) (CASC).

Paratypes. 14 workers with same data as holotype, but coded: 2 workers.2377w, 10.ii.1991; 2 workers.4469w, II.ii.1991, CASENT0170958; 1 worker.4628w, 27.ii.1991, CASENT0170958; 1 worker.6255w, 5.iii.1991, CASENT0195178; 1 worker.4342w, 15.vii.1992, CASENT0195174; 2 workers.4343w, 17.ii.1992; 2 workers.4344w, 17.ii.1992; 1 worker.4345, 17.viii.1992, CASENT0171929; 1 worker.4338w, 26.i. 1993; 1 worker.4339w, 26.i.1993 (CASC, BMNH).

M. alperti has a large, slender, relatively heavily sculptured worker which most closely resembles jugum in terms of habitus, relative dimensions and mesosomal sculpture. The main differences between them include the profile shape of the clypeus, which has a prominent and elevated false anterior margin in jugum but not in alperti ; indentation of the cephalic dorsum, which is conspicuous in alperti but minimal or absent in jugum ; and aspects of their pilosity, for instance the absence of projecting setae on the sides of the head in alperti , contrasting with their presence in jugum .

This species has been found only in lowland secondary forest and littoral forest, where it forages on the ground.

Non-paratypic material examined. Madagascar: 8 km. SW Cap Est (G.D. Alpert); 10 km. S Cap Est (GD. Alpert); Andrakaraka (B.L. Fisher et al.).