Froggattella kirbii

Collections of F. kirbii are from drier sclerophyll woodland areas (including mallee), and it is not known from wet sclerophyll woodlands or rainforests. Specimens are most often encountered as foragers on tree trunks or low vegetation although they commonly forage on the ground. All known nests have been found in rotten wood above the ground, usually in a stump or dead branch on a living tree.

Identification
Sculpturing weakly developed and uniform over the entire upper surface of the head, varying only slightly between the anterior and posterior regions; rugae on the mesopleuron well developed and superimposed on top of the underlying sculpturing, individual rugae are more or less straight and are not influenced by the underlying punctations or reticulations; posterior region of the propodeal spines in dorsal view with their outer surfaces concave.

Identification Keys including this Taxon

 * Key to Froggattella Species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Distribution Notes
Biogeographically, F. kirbii occurs in four distinct, disjunct regions: (i) south-eastern Australia, (ii) south-western Western Australia, (iii) coastal northern Queensland, and (iv) the Darwin and Kimberley regions. Its absence from the areas between south-eastern Australia and south-western Western Australia (the Nullarbor Plain), and between northern Queensland and the Darwin region (the Gulf Country) is not unexpected. These intermediate areas have significantly different climates and vegetation types than the neighbouring regions and thus may not provide suitable habitat for Froggattella. Additionally, several other ant genera show similar distribution patterns in these areas, including Acropyga, Anochetus, Hypoponera, Podomyrma and Solenopsis.

The remaining disjunction, between northern and southern coastal Queensland, is also shared with numerous other ant taxa, including Carebara, Cryptopone, Discothyrea, Epopostruma, Heteroponera, Lordomyrma, Metapone, Myopias, Myrmecina, Notostigma, Prionopelta and Pristomyrmex. The cause for the absence (or scarcity) of F. kirbii between approximately Townsville and Rockhampton is apparently climatic. This region has a lower annual mean rainfall (< 1200mm) and rainfall is more variable than the area occupied by the northern population of F. kirbii (> 1600mm), and has higher mean temperatures than areas occupied by the south-eastern populations (AUSLIG, 1986). Additionally, grasslands make up a much higher proportion of the habitats in this region when compared to areas further north and south where F. kirbii is more common (AUSLIG, 1990). It seems probable that low, unpredictable rainfall and high temperatures have combined with reduced suitable habitat (woodlands replaced by grasslands) to limit the occurrence of Froggattella in this area. At the same time, it is likely that F. kirbii (and perhaps other taxa showing a similar pattern) do occur in this region but are limited to small patches of suitable habitat. This seems especially likely for species which occur on both sides of this disjunction, but less likely in genera where distinct species occur across this gap.

Nomenclature

 *  kirbii. Acantholepis kirbii Lowne, 1865b: 333 (w.) AUSTRALIA. Wheeler, W.M. 1936a: 6 (q.m.); Wheeler, G.C. & Wheeler, J. 1951: 182 (l.). Combination in Hypoclinea: Mayr, 1870b: 954; in Dolichoderus: Dalla Torre, 1893: 159; Emery, 1894c: 228; in Froggattella: Forel, 1902h: 459. [Unjustified emendation of spelling to kirbyi: Mayr, 1876: 80; Forel, 1902h: 459.] See also: Wheeler, G.C. & Wheeler, J. 1966: 728. Senior synonym of: bispinosa, ianthina, laticeps, lutescens, nigripes: Shattuck, 1996b: 45.
 * bispinosa. Froggattella kirbyi var. bispinosa Forel, 1902h: 460 (w.) AUSTRALIA. Junior synonym of kirbii: Shattuck, 1996b: 45.
 * ianthina. Froggattella kirbyi subsp. ianthina Wheeler, W.M. 1936a: 8 (w.) AUSTRALIA. Junior synonym of kirbii: Shattuck, 1996b: 45.
 * laticeps. Froggattella kirbyi subsp. laticeps Wheeler, W.M. 1936a: 10 (w.) AUSTRALIA. Junior synonym of kirbii: Shattuck, 1996b: 45.
 * lutescens. Froggattella kirbyi subsp. lutescens Wheeler, W.M. 1936a: 9 (w.) AUSTRALIA. Junior synonym of kirbii: Shattuck, 1996b: 45.
 * nigripes. Froggattella kirbyi subsp. nigripes Wheeler, W.M. 1936a: 8 (w.) AUSTRALIA. Junior synonym of kirbii: Shattuck, 1996b: 45.

Description
Shattuck (1996) - Froggattella kirbii shows considerable variation in size. Although this variation occurs primarily between nest series (i.e. all members of a given nest series are similar in size), it is continuous between the smallest and largest and occurs throughout the range of the species. Thus while this variation appears to have a genetic component, its variability and presence in all populations of F. kirbii suggests that only a single species is involved. In addition, no evidence could be found to suggest that more than one species is present as all specimens share an overall similarity in most morphological characters, including sculpturing, colour, pilosity and general habitus (including the shape of the head, mesosoma and petiole).

Measurements Worker (n = 11) - CI 0.91-0.96; EL 0.15-0.22; EW 0.09-0.12; HL 0.69-0.95; HTL 0.55-0.75; HW 0.66-0.91; ML 0.26-0.39; PnL 0.41-0.63; PpL 0.30-0.47; SI 0.71-0.76; SL 0.46-0.65.

Worker
Length, 3.5-3.7 mm.

Head distinctly longer than broad, decidedly broader than in front, with rather straight, anteriorly converging cheeks, the sides behind the eyes convex, the posterior corners broadly rounded, the posterior border broadly and feebly excised. Eyes elliptical, situated about one and one fourth their length from the posterior clypeal suture. Mandibles convex, with rounded external border, the masticatory border with 7-8 teeth, the two apical teeth large, the others subequal, broad and directed very slightly backward. Clypeus feebly and evenly convex, its anterior border straight and transverse in the middle, sinuate on each side. Frontal area large, triangular, not impressed, indistinctly defined. Antennal scapes narrow and distinctly flattened at the base, widening apically, not reaching the posterior border of the head by a distance equal to the greatest diameter of their tips; first funicular joint twice as long as broad; joints 7-10 as broad as long, terminal joint not longer than the two preceding joints together. Pronotum without the neck as broad as long, convex above and laterally; mesonotum less than half as broad as the pronotum, rectangular, about one-third longer than broad, its dorsal outline in profile straight and sloping to the mesoepinotal impression with the dorsally projecting metanotal spiracles just behind its middle third. Epinotum about as long as the mesonotum, widened behind ventrally, its base in profile rising in a gradual even curve from the mesoepinotal impression and becoming straight and horizontal where it is continued into the spines. Seen from above the bases of the spines are angularly widened, their blunt, flattened, distal portions rather narrow and subparallel, more than twice as long as broad, slightly deflected at their tips. Declivity of epinotum shorter than the base, semicircularly concave in profile. Petiole from above fully twice as long as broad, broader in front than behind, with posteriorly slightly concave sides, the inclined scale with straight, transverse summit and rectangular corners. In profile the petiole is fully twice as long as high, the scale very blunt, projecting beyond the anterior border of the segment. Legs long and stout, the femora, especially the fore pair, distinctly thickened in the middle.

Smooth and shining, with fine, sparse, piligerous punctures; antennal scapes more densely punctulate; neck sharply, base of epinotum more superficially reticulate; mesonotum, gaster and legs microscopically and superficially shagreened; mesonotum, mesoepinotal impression and sides of epinotum regularly, sharply and longitudinally rugose, with the interrugal spaces finely and rather superficially reticulate. The rugae, which are somewhat less numerous in the mid-dorsal region of the mesonotum, pass without interruption across the impression which represents the mesoepinotal suture.

Hairs and pubescence white or pale yellowish, the former generally distributed, erect, sparse, delicate, of uneven length, longer on the body than on the appendages; pubescence fine, appresscd, moderately dense, distinct only on the clypeus, funiculi, coxae and tibiae.

Bright red or yellowish red; gaster black, with blue reflections; legs, including the coxae and sometimes the petiole, brown; tarsi yellowish; teeth of mandibles, tips of antennae and last joint of tarsi blackish.

Queen
Length, 7-8.5 mm.; fore wings 7.5 mm.

Head resembling that of the worker, but proportionally larger, broader anteriorly, with broader and more deeply concave posterior border, sharper posterior corners, larger and more convex eyes. Frontal area more distinct, but not impressed. Antennal scapes proportionally shorter, their tips reaching only to the lateral ocelli or slightly beyond. Pronotum narrowed toward the neck, much narrower than the mesonotum, which is longer than broad, produced and narrowly rounded anteriorly, scutellum as long as broad, epinotum subtrapezoidal from above, as long as broad, narrowed posteriorly, its base in profile moderately convex, somewhat sloping, passing rather abruptly into the declivity, which is distinctly concave and not more than a third as long as the base. The epinotal spines of the worker are represented by a very small, low welt on each side at the posterior end of the base. Petiole from above only about one-fourth longer than broad, as broad behind as in front, with concave sides and with the scale of the worker replaced by a transversely elliptical node, twice as broad as long, flattened above, with nearly perpendicular anterior and sloping posterior surface and the posterior peduncle much shorter than the node. Gaster long, with subparallel sides, the first segment narrowed anteriorly, with concave, marginate median border and sharply marginate anterior corners; in profile with the base deeply concave at its junction with the postpetiole.

Subopaque, or lustrous; legs and petiole more shining; head and thorax punctate-rugulose, the rugules delicate, longitudinal on the clypeus, front and mesonotum transverse on the occiput, pronotum and base of epinotum, where they are arcuate and coarser. Mandibles finely reticulate and coarsely and sparsely punctate. Petiole, gaster, scapes and legs finely reticulate-punctate.

Hairs as in the worker but the appressed pubescence much more abundant, longer and investing all parts of the body except the petiole, though nowhere concealing the integument except on the gaster where it becomes very dense and snow white at the posterior border of each segment, thus forming a rather broad, sharply defined, band. The pubescence of each band converges sharply at the mid-dorsal line but turns laterally on each side, becoming transverse on the sides of the gaster.

Head, thorax and petiole dull yellowish red; gula, epinotum and petiole somewhat paler; sides of clypeus, front and vertex blackish brown as are also the scutellum, a large spot on the posterior portion of the mesonotum, continued forward as a narrow median vitta and two broader parapsidal vittae and a large elliptical spot on each side, covering the posterior portion of the pronotum and the mesopleurae. Legs dark brown, with the coxae and extensor surfaces of the femora and tibiae black; gaster deep black except for the sharply contrasting fasciae of dense white pubescence. Wings colorless, with pale brown veins and dark brown pterostigma.

Male
Length, 3-3.5 mm.

Head small, about one-fourth broader than long through the eyes, flattened; ocelli transversely elliptical, the anterior one surrounded in front by a deep semicircular groove, the posterior directed laterally and connected by a straight, thick, transverse welt. Clypeus with a circular median convexity, its anterior border rounded and somewhat projecting in the middle, sinuate on each side, frontal area convex, triangular, slightly longer than broad. Antennal scapes only one and one-half times as long as broad; first funicular joint slightly shorter than the second, which like all the joints except the last is nearly as broad as long. Thorax much broader than the head, the large mesonotum as broad as long; scutellum as long as broad, shaped like the mesonotum but reversed; epinotum evenly rounded and sloping in profile, without distinct base and declivity. Petiole nearly twice as broad as long, wider behind than in front, in profile higher than long, the node broadly rounded and medially impressed above; postpetiole broadly articulated to the gaster so that the anterior slope of the node is long and steep, the posterior slope very short and rounded. Stipites of genitalia very small, subtriangular, their tips rounded, their bases very largely membranous; volsellae long, slender, falcate, with acute tips; sagittae broad, subelliptical, with finely serrate ventral borders.

Shining, finely reticulate or shagreened, with fine scattered, piligerous punctures.

Pilosity as in the worker but shorter and sparser; appressed pubescence generally distributed, as in the female, but shorter and much more dilute, not dimming the shining integument, absent on the petiole.

Black; mandibles, mouth parts, tibiae, tarsi, petiole and genitalia piceom; first funicular joint and articulations, veins and pterostigma of wings paler and more yellowish brown.