Vitsika astuta 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 : 74-76

Vitsika astuta Bolton & Fisher sp. n.

(Figs 84-86, Map 150)

WORKER (holotype in parentheses). TL 3.2-3.7 (3.6), HL 0.74-0.85 (0.80), HW 0.60-0.71 (0.69), CI 82-86 (86), SL 0.54-0.66 (0.60), SI 85-90 (87), PW 0.46-0.55 (0.52), WL 0.88-1.08 (1.02) (10 measured).

Eye with 8-9 rows of ommatidia, and with 9-11 ommatidia in the longest row; EL 0.17-0.21 (EL/HW 0.27-0.30). MfL 0.66-0.80 (MfL/HW 1.06-1.13). Median portion of clypeus with two carinae on each side, the area between them smooth. In profile, the dorsal outline of the propodeum flat to shallowly convex, without a distinct peak in its outline posterior to the mesonotal-propodeal junction. Propodeal declivity without transverse costulae, or at most with weak vestiges present. Diameter of annulus of propodeal spiracle is at least equal to the thickness of the propodeal spine at its midlength. Petiole node in profile cuneate, slightly inclined anteriorly, entirely unsculptured; in posterior view low and broad, its dorsal surface broadly rounded. Height of petiole node in posterior view (from midpoint of the dorsal margin of the foramen to the apex) 0.90-1.00 x its maximum width. In dorsal view postpetiole 1.20-1.32 x broader than long; maximum width of postpetiole 0.94-1.04 x the length of a propodeal spine; maximum width of postpetiole 0.86-0.96 x the distance between the apices of the propodeal spines. Postpetiole node in profile relatively short and strongly convex dorsally, the length of the node in profile is distinctly less than the height of the segment. Disc of postpetiole entirely smooth, glossy, without trace of lateral longitudinal costulae. Dorsal (outer) surface of the metatibia with a few suberect that are setae long and fine, at least as long as the maximum tibial width. Full adult colour yellow.

QUEEN (gyne). Only alates known. HL 0.88-0.90, HW 0.75-0.76, CI 84-85, SL 0.63-0.66, SI 84-87, PW 0.62-0.64, WL 1.26-1.28, maximum width of mesoscutum 0.56-0.60, maximum length of mesoscutum 0.56-0.60, MfL 0.82 (2 measured).

MALE: unknown.

Holotype worker, Madagascar: Prov. Antsiranana, R.S. Manongarivo, 17.3 km. 218° SW Antanambao, 1580 m., 14°01.3'S, 48°25.1'E, 27.x.1998, sifted litter (leaf mold, rotten wood), montane rainforest, BLF 1970(50)-13, (no CASENT number) (B.L. Fisher) (CASC).

Paratypes. 6 workers, 3 dealate queens, with same data as holotype and all BLF 1970: workers, (05) CASENT0192036, (11) CASENT0127746, (16) CASENT0192020, (22)-13 (no CASENT number), (50) CASENT019202, (50)-12 (no CASENT number); queens, (22)-11 (no CASENT number), (49)-9 (no CASENT number), (no BLF code) CASENT0178900 (CASC, BMNH).

The largest of the yellow species of Vitsika , astuta actually appears to be more closely related to darkly coloured species such as miranda and obscura. Comments on their separation are given under those names.

Specimens of astuta have been found in leaf litter, in rotten logs, and in living plant stems, in rainforest.

Non-paratypic material examined. Madagascar: Prov. Antsiranana, R.S. Manongarivo, SW Antanambao (B.L. Fisher); Prov. Toliara, NW Enakara, Res. Andohahela (B.L. Fisher).