Technomyrmex quadricolor

The type was taken “among fallen leaves.”

Identification
Bolton (2007) - A member of the T. sophiae complex in the Technomyrmex albipes group. The thick of sculpture on the head and pronotum easily isolate this striking species, together with its close relatives discussed under Technomyrmex sophiae, from all other Australian congeners. The unique colour pattern of quadricolor distinguishes it from sophiae, Technomyrmex nitens and Technomyrmex furens, all of which have the head, mesosoma and gaster uniformly blackish brown to black and do not have funiculus segments 2 - 11 darker than the scape.

Intercastes between workers and queens appear to be fairly' common in quadricolor (and also in its close relatives). Several basically worker-like specimens have been noted which have 3 fully developed ocelli. A couple of intercastes examined have a size-reduced but very queen-like complement of mesosoma sclerites, including a strongly differentiated mesoscutellum and a complete dorsal suture separating mesoscutum from mesoscutellum.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Biology
All the material examined was collected from trees, manually or by pyrethrum knock-down, but I would be surprised if quadricolor did not also forage on the ground like most other members of the fauna. (Bolton 2007)

Nomenclature

 *  quadricolor. Aphantolepis quadricolor Wheeler, W.M. 1930d: 44, fig. 2 (w.) AUSTRALIA. Combination in Technomyrmex: Brown, 1953h: 5. See also: Bolton, 2007a: 115.

Worker
Head slightly longer than broad, distinctly narrowed anteriorly, with broadly rounded posterior corners and entire posterior border. Eyes moderately large and convex, placed a little in front of the middle of the sides of the head. Surface of clypeus rather flat, slightly projecting but scarcely subcarinate in the middle, the anterior border transverse, feebly sinuate on each side. Mandibles with nearly straight external and somewhat oblique apical borders, the latter with seven small, acute teeth, which are somewhat crowded and subequal, except the basal and third tooth from the apex, which are smaller. Antennal scapes extending nearly one-third their length beyond the posterior border of the head; first funicular joint twice as long as broad, nearly as long as the two succeeding joints together; joints 2-10 only slightly longer than broad, the terminal joint as long as the two penultimate joints together. Pronotum from above trapezoidal, broader than long, broader anteriorly than posteriorly, in profile feebly convex above. Mesonotum much narrower than the pronotum, slightly longer than broad, as broad in front as behind, with subparallel, slightly concave sides, in profile rounded and sloping backward to the pronounced mesoepinotal constriction. Epinotum broader than long, subrectangular from above, slightly broader behind through the prominent spiracles than in front; in profile with very convex, rounded base passing without an angle into the shorter, concave declivity. Petiole small, nearly twice as long as broad, from above regularly elliptical, except at the posterior border where it is excised for the articulation of the gaster. A very feeble trace of the absent node is represented by the narrowly rounded anterior end of the fiat dorsal surface; the ventral surface is distinctly convex. Gaster broad anteriorly, rapidly tapering and pointed posteriorly, the anterior truncated surface of the first segment longitudinally impressed in the middle for the accommodation of the petiole. Legs rather stout.

Smooth and shining, especially the dorsal surface of the head, the pronotum and the gaster, meso- and epinotum more subopaque, very finely and densely punctate or reticulate. Mandibles smooth, with a few scattered piligerous punctures.

Erect hairs brownish, pointed, few in number, of unequal length, arranged as pairs of macrochretre on the head, pro- and mesonotum as in some species of Paratrechina (subgen. Nylanderia). Gaster both dorsally and ventrally with similar but shorter hairs, and the head and gaster also with more numerous short, suberect hairs or coarse pubescence. Antennal scapes and legs with pale, long, oblique, rather abundant pubescence.

Head and thorax yellowish red, the former a little darker, with a fuscous doud on the vertex. Mandibles, petiole, legs, scapes and first funicular joint clear yellow; remaining funicular joints dark brown; mandibular teeth and gaster black; terminal tarsal joints reddish.

Bolton (2007) - TL 2.9 - 3.3, HL 0.62 - 0.70, HW 0.58 - 0.64, SL 0.61 - 0.66, PW 0.40 - 0.50, WL 0.84 - 0.92 (12 measured). Indices: CI 90 - 97, SI 100 - 106, OI 25 - 27 EPI 88 - 96, DTI 120 -133.

Dorsum of head behind clypeus with numerous setae: in profile 3 - 4 on frontal carina; 2 pairs at level of eye; 2 - 3 pairs from level of posterior margin of eye to posterior margin of head. Setal pair nearest to posterior margin of head the longest, much longer than maximum diameter of eye. Dorsum of head unsculptured, smooth and shining except for setal pits. With head in full-face view the eyes close to the midlength and their outer margins just break the outline of the sides. Anterior clypeal margin almost transverse, with only a minute median indentation. Posterior margin of head with a very slight median indentation. Number of setal fairs on mesosoma: pronotum 2 - 5; mesonotum 2 - 3; lateral margin of propodea declivity 2 - 3. Pronotum smooth and shining. Propodeum in profile with a weakly convex dorsum that rounds broadly into the declivity. Gastral tergites 1 - 4 each with numerous setae, the longest on the first tergite much longer than the maximum diameter of the eye. First gastral tergite shining, unsculptured except for setal pits. Head, mesosoma and petiole yellow to light brownish yellow; gaster very dark brown to black and very strongly contrasting. Antenna characteristically, in specimens with full adult colour, with funiculus segments 2 – 11 darker than scape plus first funicular segment. Middle and hind coxae usually slightly lighter than mesosoma; femora and tibiae, except for bases and apices, somewhat darker; tarsi light. Scapes and tibiae may have the minute pubescence slightly elevated but setae are absent. Pubescence on first gastral tergite distinctly more sparse than on tergites 2 - 4.

Type Material
Bolton (2007) - Holotype worker, Australia: Queensland, Cairns Distr. (A. M. Lea) [examined: holotype mostly lost, only fragments on pin]. Apart from a few leg segments the holotype of quadricolor has been missing from its mount for many years (see Brown, 1953). However, these leg segments are sufficient to isolate quadricolor from all other Australian Technomyrmex and adequately confirm the identity of the species.



References based on Global Ant Biodiversity Informatics

 * Bolton B. 2007. Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker caste. Contributions of the American Entomological Institute 35(1): 1-150.
 * Wheeler W. M. 1930. Two new genera of ants from Australia and the Philippines. Psyche (Cambridge) 37: 41-47.