Vitsika breviscapa 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 : 76-78

Vitsika breviscapa Bolton & Fisher sp. n.

(Figs 87-89, Map 151)

WORKER (holotype in parentheses). TL 2.3-2.6 (2.6), HL 0.58-0.70 (0.52), HW 0.50-0.59 (0.52), CI 82-86 (83), SL 0.38-0.44 (0.39), SI 73-76 (75), PW 0.34-0.40 (0.34), WL 0.68-0.80 (0.70) (15 measured).

Eye with 6-7 rows of ommatidia, and with 8-9 ommatidia in the longest row; EL 0.14-0.17 (EL/HW 0.28-0.30). MfL 0.46-0.52 (MfL/HW 0.85-0.92). Propodeal spines in profile short, diameter of annulus of propodeal spiracle is greater than the thickness of the propodeal spine at its midlength. Petiole node low and relatively long, usually appearing quite squat and blocky in profile. Anterior face of petiole node rises steeply to the anterodorsal angle; the dorsal face is long and slopes down posteriorly; there is usually a blunt angle posteriorly between the dorsal face and the short posterior face, but this angle is sometimes rounded and inconspicuous. Height of petiole node in posterior view (from midpoint of the dorsal margin of the foramen to the apex) 0.95-1.07 x its maximum width. In dorsal view postpetiole 1.10-1.20 x broader than long; maximum width of postpetiole

1.25-1.60 x the length of a propodeal spine; maximum width of postpetiole 1.00-1.22 x the distance between the apices of the propodeal spines. Length of postpetiole node in profile slightly less than the height of the segment. Disc of postpetiole entirely smooth, glossy. Full adult colour yellow.

QUEEN (gyne). Only ergatoids known (e.g. CASENT0496288). HL 0.68-0.72, HW 0.57-0.62, CI 83-86, SL 0.44-0.46, SI 71-78, PW 0.41-45, WL 0.82-0.84, EL 0.17-0.18 (EL/HW 0.28-0.29), MfL 0.54-0.56 (MfL/HW 0.90-0.95) (4 measured). Usually with only the median ocellus developed, and frequently this ocellus very reduced; sometimes with 3 ocelli, the median distinct and the posterior pair reduced. The mesonotum is scarcely more inflated than in the workers. It is possible that the largest individuals regarded as workers here may actually be extreme ergatoids.

MALE. HL 0.52-0.54, HW 0.42-0.43, CI 78-83, SL 0.16-0.18, SI 37-43, mesoscutum width at maximum 0.40-0.42, WL 0.82-0.84, EL 0.24, MfL 0.60 (2 measured). Propodeum unarmed; propodeal dorsum unsculptured; propodeal dorsum and declivity without trace of a median longitudinal carina. Postpetiole in dorsal view longer than broad. Dorsal arc of eye, from midpoint of anterior margin to midpoint of posterior margin, bounded by a marked impression in the cuticle of the head capsule. Scape only very slightly longer than funiculus segment 2 (antennal segment 3); scape about equal in length to funiculus segment 8; funiculus segment 9 easily the longest antennal segment (ca 0.24); funiculus segments 10 and 11 each about equal in length to the scape; apical antennal segment (funiculus segment 12) almost 2 x SL. Colour dull yellow, with infuscated patches, especially dorsum of head around the ocelli.

Holotype worker (top specimen of 3 on pin), Madagascar: Prov. Toamasina, Mont. Akirindro, 7.6 km. 341° NNW Ambinanitelo, 15°17.3'S, 49°32.9'E, 600 m., 17-21.iii.2003, ex Melastomataceae, BLF 8284, CASENT0496230 (Fisher et al.) (CASC).

Paratypes. 2 workers mounted on pin below holotype; 2 workers with same data but CASENT0496231 (CASC).

The immediate distinguishing features of breviscapa workers are the combination of yellow colour, relatively short scapes (the shortest in the genus), metafemur that is always shorter than HW, and propodeal spines that are shorter than in all other species except crebra . Confusion with crebra should be impossible as the postpetiole in crebra is entirely densely sculptured, its postpetiole in dorsal view is 1.35-1.45 x broader than long, and its SI is 85-91. In addition, in crebra , the anterior curvature of the outline of the eye in profile is very similar to the posterior curvature, whereas in breviscapa the eye is more obviously tear-drop shaped, with an outline that is much more narrowly rounded and pointed anteriorly than posteriorly.

A few specimens of breviscapa have been recovered from leaf litter samples in rainforest, but the great majority were captured in association with plants of the family Melastomataceae. The biology of the ant-plant association is not known, but breviscapa appears to be the only known member of Vitsika that is plant-associated.

Non-paratypic material examined. Madagascar: Prov. Toamasina, Mont. Anjanaharibe, NNE Ambinanitelo (Fisher et al.); Prov. Toamasina, Mont. Akirindro, NNW Ambinanitelo (Fisher et al.).