Melophorus minimus

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  minimus. Melophorus minimus Heterick, Castalanelli & Shattuck, 2017: 204, fig. 43 (w.) AUSTRALIA.

Worker
(n = 8): CI 95–111; EI 25–45; EL 0.18–0.19; HL 0.41–0.70; HW 0.40–0.78; ML 0.55–0.90; MTL 0.26–0.44; PpH 0.06–0.09; PpL 0.23–0.39; SI 65–88; SL 0.35–0.50.

Minor. Head. Head approximately oval with straight sides; posterior margin of head planar to strongly convex; frons shining with superficial shagreenation or microreticulation only, or matt or with weak sheen, microreticulate or microreticulate-shagreenate; frons consisting exclusively or almost exclusively of well-spaced, appressed setae only (small, erect setae, if present, usually confined to ocular triangle or posterior margin of head). Eye large (eye length ≥ 0.50 × length of side of head capsule); in full-face view, eyes set at about midpoint of head capsule; in profile, eye set anteriad of midline of head capsule; eyes elliptical or slightly reniform. In full-face view, frontal carinae straight or weakly convex; frontal lobes curved inward in front of antennal insertion. Anteromedial clypeal margin broadly and evenly convex and protrusive; clypeal psammophore set below midpoint of clypeus; palp formula 6,4. Five mandibular teeth in minor worker; mandibles triangular, weakly incurved; third mandibular tooth distinctly shorter than apical tooth and teeth numbers two and four; masticatory margin of mandibles approximately vertical or weakly oblique. Mesosoma. Integument of pronotum, mesonotum and mesopleuron matt or with weak sheen and microreticulate throughout, or pronotum smooth and shining, mesonotum shining and superficially microreticulate, mesopleuron densely microreticulate and may be almost matt; anterior mesosoma in profile smoothly rounded anteriad, thereafter pronotum and whole of mesonotum flattened and on same plane as propodeum; erect pronotal setae absent; in profile, metanotal groove shallow, broadly V or U-shaped; propodeum matt or with a weak sheen and microreticulate; propodeum angulate, propodeal angle blunt; length ratio of propodeal dorsum to its declivity between 3:2 and 4:3; erect propodeal setae always absent; appressed propodeal setulae long, each reaching setae behind and in front, but not forming pubescence; propodeal spiracle situated on or beside declivitous face of propodeum, and shorter (length < 0.50 × height of propodeum). Petiole. In profile, petiolar node squamiform; in full-face view, shape of petiolar node uniformly rounded; node shining and smooth throughout. Gaster. Gaster smooth and glossy; pilosity of first gastral tergite consisting of well-spaced short, inconspicuous, appressed setae only, erect setae always absent. General characters. Colour of head and mesosoma dark brown to blackish-brown, mesosoma variably brown-and-orange-tan.

Major. Head. Head square; posterior margin of head planar or weakly concave; cuticle of frons shining and smooth except for piliferous pits and a few striolae around antennal insertions and Frontal carinae; frons consisting exclusively or almost exclusively of well-spaced, appressed setae only (small, erect setae, if present, usually confined to ocular triangle or posterior margin of head). Eye moderate (eye length 0.20–0.49 length of head capsule); in full-face view, eyes set at about midpoint of head capsule; in profile, eye set anteriad of midline of head capsule; eyes elliptical. In full-face view, frontal carinae straight or weakly convex; frontal lobes curved inward in front of antennal insertion. Anterior clypeal margin broadly and evenly convex; clypeal psammophore set at or above midpoint of clypeus; palp formula 6,4. Five mandibular teeth in major worker; mandibles triangular, weakly incurved; third mandibular tooth distinctly shorter than apical tooth and teeth numbers two and four; masticatory margin of mandibles approximately aligned vertically or weakly oblique. Mesosoma. Integument of pronotum, mesonotum and mesopleuron matt or with weak sheen and microreticulate throughout; anterior mesosoma in profile pronotum smoothly rounded anteriad and flattened posteriad, mesonotum narrowly convex; erect pronotal setae short, (i.e., shorter than length of eye) and unmodified; in profile, metanotal groove shallow, broadly V- or U-shaped; propodeum shining, dorsum and declivitous face of propodeum mainly smooth, but with weak to strong vertical striolae arising from metapleuron; propodeum wedge-shaped, tapering dorsad; length ratio of propodeal dorsum to its declivity between 3:2 and 4:3; erect propodeal setae absent; appressed propodeal setae short, separated by more than own length and inconspicuous; propodeal spiracle situated on or beside declivitous face of propodeum, and shorter (length less than 0.50 × height of propodeum). Petiole. In profile, petiolar node squamiform; in full-face view, shape of petiolar node uniformly rounded; node shining and smooth with vestigial microreticulation anteriad. Gaster. Gaster smooth and glossy; pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with regularly spaced appressed setae. General characters. Colour concolorous light brown or orange tan.

Type Material
Holotype minor worker from Emu Camp, Victoria Desert, 5 October 1976, P.J.M. Greenslade, (8), h1, [ANIC32-900172]. Paratypes: major and media worker from Gawler Range, South Australia, 4 October 1972, P.J.M. Greenslade, (2) [ANIC32-900171] (ANIC); 3 minor workers from Fowlers Gap, New South Wales, 18 November 1979, P.J.M. Greenslade, (4) (ANIC); 2 minor workers from Gawler Ranges, South Australia, 4 October 1972, P.J.M. Greenslade, (2) A ; 2 minor workers from Brookfield Conservation Park 34°19'S, 139°29'E, South Australia, 29 October 1991, S. Shattuck, # 2525.7 [ANIC32-900098] ; 2 minor workers from Cunnamulla, Queensland, 17 September 1974, P.J.M. Greenslade, (8), gpt ; 2 minor workers from 5 km NE Koonamore HS, South Australia, 26 February 1973, P.J.M. Greenslade, (1) K1/lo(?) 13 ; minor worker from 7 km NE Leinster, Western Australia, 16 September 1988, B. Heterick, soil, native vegetation, rural environment, 451, 8MelBh25 [JDM32-004550].

Etymology
Compound of Greek mikros (‘small’) plus Latin reticulatus (‘netted’); adjective in the nominative singular.