Vitsika suspicax 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 : 91-92

Vitsika suspicax Bolton & Fisher sp. n.

(Figs 114-116, Map 160)

WORKER (holotype in parentheses). TL 3.0-3.4 (3.3), HL 0.66-0.72 (0.72), HW 0.53-0.60 (0.56), CI 79-83 (79), SL 0.46-0.52 (0.47), SI 82-89 (84), PW 0.41-0.48 (0.44), WL 0.84-0.94 (0.90) (12 measured).

Eye with 7-8 rows of ommatidia, and with 9-10 ommatidia in the longest row; EL 0.16-0.19 (EL/HW 0.29-0.32). MfL 0.54-0.64 (MfL/HW 0.98-1.08). Diameter of annulus of propodeal spiracle equal to or greater than the thickness of the propodeal spine at its midlength. Petiole node in profile more or less erect with respect to the peduncle, the node not obviously inclined posteriorly; node usually without a defined posterior surface that is distinctly differentiated from the dorsum. In general the ascending anterior face of the node terminates in a blunted anterodorsal angle, which is the highest point of the node. Behind this the dorsum slopes downward posteriorly and rounds broadly and evenly into the sloping posterior face. In some specimens the two surfaces meet through a more obvious rounded angle. Sculpture of petiole node faint to vestigial: in some specimens the node with faint superficial microsculpture only; in others a few extremely weak and fine striae ascend the anterior surface, but when these occur they never traverse the sides near the dorsum, nor overlap onto the posterior surface. Height of petiole node in posterior view (from midpoint of the dorsal margin of the foramen to the apex) 0.87-0.96 x its maximum width. In dorsal view postpetiole 1.08-1.20 x broader than long; maximum width of postpetiole <1.20 x the length of a propodeal spine; maximum width of postpetiole 0.93-1.00 x the distance between the apices of the propodeal spines. Length of postpetiole node in profile about equal to the height of the segment. Dorsum of postpetiole usually entirely smooth on the disc; weak punctulate sculpture is usually present posteriorly and laterodorsally, and weak laterodorsal longitudinal costulae are sometimes present. Full adult colour yellow.

QUEEN (gyne). May be ergatoid (e.g. CASENT0914211), alate, or intermediate between the two (e.g. CASENT0914196). Two extreme ergatoid specimens are known; one lacks ocelli and the other has a small median ocellus present. In both, the mesonotum is somewhat more swollen than in the worker, and the mesopleuron lacks a transverse sulcus. Both are about equal in size to the largest specimen currently regarded as a worker, HL 0.73-0.74, HW 0.58-0.59, CI 78-81, SL 0.52-0.53, SI 90, PW 0.45-0.46, WL 0.96, MfL 0.62 (2 measured). Two intermediate specimens (one with gaster missing) are known; both have three distinct ocelli, and a distinct transverse sulcus on the mesopleuron. The mesosoma is almost worker-like but is larger and has weakly differentiated flight sclerites, a fused mesoscutum plus mesoscutellum instead of a simple mesonotum, and the metanotum is vestigially present. In dorsal view the pronotum is fused to the mesoscutum, separated from it only by an impression, there is no suture, and the reduced mesoscutum and mesoscutellum are fused; there are no traces of wings. Dimensions of the intermediate forms fall broadly within the worker range: HL 0.69-0.70, HW 0.58, CI 83-84, SL 0.47-0.48, SI 81-83, PW 0.44-0.54, WL 0.88, MfL 0.57-0.58 (1 measured). Four dealate queens are known, three of which are included in the type-series. These possess a swollen mesosoma with a full complement of flight sclerites, have 3 distinct ocelli, and have a conspicuous transverse sulcus on the mesopleuron. Cephalic dimensions of these specimens are only slightly larger than in the workers, but the mesosoma is more voluminous: HL 0.73-0.75, HW 0.60-0.61, CI 81-84, SL 0.52-0.53, SI 85-87, PW 0.53-0.56, WL 1.02-1.10, maximum width of mesoscutum 0.48-0.52, maximum length of mesoscutum 0.55-0.56, MfL 0.65-0.67 (3 measured).

MALE: unknown.

Holotype worker, Madagascar: Prov. Antsiranana, P.N. Marojejy, 25.7 km. 32° NNE Andapa, 21-23.xi.2003, 1575 m., 14°26.7'S, 49°44.5'E, sifted litter, montane rainforest, BLF 9242(L0), CASENT0040798 (Fisher et al.) (CASC).

Paratypes. 2 workers and 3 dealate queens, with same data as holotype: workers, BLF 9242(4), CASENT0040785; BLF 9242(9), CASENT0040788; queens, BLF 9242(L0), CASENT0040796; BLF 9242(2), CASENT0040783; BLF 9242(21), CASENT0040794 (CASC). [Note that two workers, with same data as holotype but BLF 9242(8), CASENT0040786 (head missing) and CASENT0040787 (head, waist segments and gaster missing), are omitted from the type-series as they are badly damaged.]

Separated only weakly from procera by the form and sculpture of the petiole node, which in suspicax is more slender and generally less angular in profile, with a broader and more shallowly convex dorsal margin in posterior view, and always more feebly and superficially sculptured. As mentioned under procera , it may transpire that suspicax and procera are respectively less and more strongly sculptured variants of a single species. A single worker from Ankarana (CASENT0275352), may represent a very closely related but separate species. This specimen is at the top end of the size range given above (HL 0.72, HW 0.60, SL 0.52, MfL 0.64), but has a higher and more slender petiole node than is usual, more strongly developed rugose sculpture on the mesosoma, and a metanotal groove that in profile is broader and more obviously concave. We consider this specimen as suspicax until more material indicates otherwise.

All material was retrieved from litter samples or from yellow pan traps, in montane rainforest.

Non-paratypic material examined. Madagascar: Prov. Antsiranana, P.N. Marojejy (Fisher et al.); Prov. Antsiranana, P.N. Marojejy, NNE Andapa (Fisher et al.); Prov. Antsiranana, RNI Marojejy, NW Manantenina (E.L. Quinter); Prov. Toamasina, WSW Befingotra, Res. Anjanaharibe-Sud (B.L. Fisher); Prov. Toamasina, Ankerana (B.L. Fisher et al.);