Vitsika acclivitas 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 : 73-74

Vitsika acclivitas Bolton & Fisher sp. n.

(Figs 81-83, Map 149)

WORKER (holotype in parentheses). TL 2.5-3.0 (2.7), HL 0.56-0.66 (0.61), HW 0.48-0.55 (0.53), CI 83-87 (87), SL 0.38-0.46 (0.42), SI 80-85 (80), PW 0.35-0.45 (0.40), WL 0.66-0.80 (0.77) (10 measured).

Eye with 6 rows of ommatidia, and with 7-8 ommatidia in the longest row; EL 0.13-0.16 (EL/HW 0.26-0.29). MfL 0.44-0.56 (MfL/HW 0.96-1.01). Propodeal spiracle relatively small, diameter of annulus of propodeal spiracle is usually slightly less than the thickness of the propodeal spine at its midlength. Petiole node large, tall and characteristically shaped: in profile the dorsal surface of the peduncle is continuous with the anterior face of the node, the two run together through a very obtuse angle, so that the anterior face of the node slopes upwards and posteriorly only shallowly relative to the dorsum of the peduncle. The anterior face of the petiole node rises to the short, narrowly rounded dorsum, and the posterior face has about the same degree of slope as the anterior. Height of petiole node in posterior view (from midpoint of the dorsal margin of the foramen to the apex) 0.82-0.89 x its maximum width. In dorsal view postpetiole 1.10-1.18 x broader than long; maximum width of postpetiole 1.15-1.36 x the length of a propodeal spine; maximum width of postpetiole 0.90-1.00 x the distance between the apices of the propodeal spines. Length of postpetiole node in profile about equal to the height of the segment. Disc of postpetiole usually with some weak punctulate sculpture, especially on the posterior half. Full adult colour yellow.

QUEEN (gyne). Only alates known; may be polygynous as several queens appears in one series. HL 0.65-0.70, HW 0.56-0.60, CI 86-88, SL 0.44-0.47, SI 77-79, PW 0.52-0.56, WL 0.90-0.98, maximum width of mesoscutum 0.50-054, maximum length of mesoscutum 0.48-0.53, MfL 0.56-0.60 (MfL/HW 0.85-1.00) (3 measured). With three distinct ocelli, a full complement of flight sclerites and a conspicuous sulcus across the mesopleuron. The shape of the petiole node parallels that seen in the worker.

MALE: unknown.

Holotype worker, Madagascar: Prov. Antsiranana, Foret Bekaraoka, 6.8 km. 60° ENE Daraina, 7-9.xii.2003, 13°10.0'S, 49°42.6'E, sifted litter, tropical dry forest, BLF 9872(22), CASENT0044902 (Fisher et al.) (CASC).

Paratypes. 1 worker and 1 dealate queen, with same data as holotype and all BLF 9872: worker, (2) CASENT0044917; queen, (2) CASENT0044916 (CASC).

Among the small, yellow species of Vitsika , acclivitas is distinguished by its much less erect petiole node. The node shape that seems most similar is that of venustas , but in that species the anterior face of the petiole node is not as shallowly inclined, and the postpetiole in profile has a node that is visibly longer than the height of the segment.

Almost all the specimens were from leaf litter samples in tropical dry forest. Only the two queens that constitute the NE Andapa sample were from rainforest.

Non-paratypic material examined. Madagascar: Prov. Antsiranana, Foret Antsahabe, W Daraina (Fisher et al.); Prov. Antsiranana, Res. Analamerana, Anivorano-Nord (B.L. Fisher); Prov. Antsiranana, P.N. Marojejy, NE Andapa (Fisher et al.).