Melophorus fulgidus Heterick, Castalanelli & Shattuck

Heterick, Brian E., Castalanelli, Mark & Shattuck, Steve O., 2017, Revision of the ant genus Melophorus (Hymenoptera, Formicidae), ZooKeys 700, pp. 1-420 : 90-93

Melophorus fulgidus Heterick, Castalanelli & Shattuck sp. n.

Types.

Holotype minor worker (bottom ant) from Coward Springs 29.24S, 136.49E, South Australia, 22 September 1972, J. E. Feehan, ANIC Ant Vial 16.70 [ANIC32-066609] (ANIC). Paratypes: major and minor worker on same pin with same details as holotype (ANIC); queen and 2 minor workers from Coward Springs 29.24S, 136.49E, South Australia, 22 September 1972, J. E. Feehan, ANIC Ant Vial 16.70 [ANIC32 900006] (MCZ).

Diagnosis.

Melophorus fulgidus is a member of the M. aeneovirens species-group (in full-face view, the anterior clypeal margin convex, apron-like and covering whole or part of the retracted mandible, except in M. nemophilus , the medial clypeal sector often produced so that it is protrusive when seen in profile; the psammophore frequently with coarse and well-separated ammochaetae, these always placed on or just above anterior margin; in profile, the propodeum elongate and oblique or broadly rounded), and the M. aeneovirens species-complex (in full-face view, psammophore ranged along or just above anterior margin of clypeus and following the curve of the margin; anterior margin of clypeus broadly medially produced, and often with central notch that may be deeply impressed, but is never acuminate at its midpoint; metatibia with maximum of two rows of preapical spines). Melophorus fulgidus is not particularly distinctive, but can be identified in having, in full-face view, the eyes of the minor worker placed high on the head and breaking the outline of head capsule where the broadly convex posterior margin of the head meets the sides. Unlike most membes of the species-complex, both major and minor worker are glabrous, smooth and shining, with the appressed setae spaced much greater than their own length apart. In profile, the major worker has a flat mesonotum that overarches the pronotum, and, in full-face view, a protruding, weakly bifurcate anteromedial clypeal margin. This combination of characters separate M. fulgidus from other Melophorus in its species-complex, but careful checking is required. The species appears to be very localised in the Flinders Ranges in mid-north South Australia.

Minor worker description.

Head. Head approximately oval with straight sides; posterior margin of head strongly convex; frons shining with superficial shagreenation or microreticulation only; 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 side of head capsule); in full-face view, eyes set above 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, convergent posteriad; frontal lobes straight in front of antennal insertion. Anteromedial clypeal margin narrowly protrusive anteromedially, the protrusion with a square border; clypeal psammophore set at or just above anterior clypeal margin; 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 shining and mainly smooth, vestigial shagreenation most noticeable on humeri and mesopleuron; anterior mesosoma in profile convex anteriad, mesonotum often slightly overlapping pronotum, mesosoma planar or slightly sinuate posteriad; erect pronotal setae absent; in profile, metanotal groove shallow, broadly V or U-shaped; propodeum shining and uniformly striolate; propodeum smoothly rounded or with indistinct angle; propodeal dorsum and declivity confluent; erect propodeal setae always absent; appressed propodeal setulae short, separated by more than own length and inconspicuous; 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 shining, shagreenate ('LP record’ appearance); pilosity of first gastral tergite consisting of well-spaced short, inconspicuous, appressed setae only, erect setae always absent. General characters. Colour brown.

Major worker description.

Head. Head square; posterior margin of head weakly concave; cuticle of frons matt or with weak sheen, indistinctly 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 moderate (eye length 0.20-0.49 length of head capsule); in full-face view, eyes set above midpoint of head capsule; in profile, eye set anteriad of midline of head capsule; eyes elliptical. In full-face view, frontal carinae straight, convergent posteriad; frontal lobes straight in front of antennal insertion. Anterior clypeal margin narrowly convex and protruding anteromedially, clypeal midpoint notched; clypeal psammophore set at or just above anterior clypeal margin; 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 moderately shining and shagreenate throughout; anterior mesosoma in profile convex anteriad, mesonotum overlapping pronotum, planar or slightly sinuate posteriad; erect pronotal setae absent; in profile, metanotal groove shallow, broadly V- or U-shaped; propodeum shining and shagreenate; propodeum always smoothly rounded; propodeal dorsum and declivity confluent; erect propodeal setae absent; 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 generally rounded with median indentation; node shining and faintly shagreenate-microreticulate. Gaster. Gaster shining, shagreenate ('LP record’ appearance); pilosity of first gastral tergite consisting of well-spaced short, inconspicuous, appressed setae only, erect setae always absent. General characters. Colour of head orange, remainder of body brown.

Measurements.

Worker (n = 2): CI 94-109; EI 19-29; EL 0.26-0.36; HL 0.94-1.75; HW 0.88-1.90; ML 1.54-2.18; MTL 1/03-1.37; PpH 0.15-0.20; PpL 0.69-0.90; SI 85-152; SL 1.34-1.61.

Comments.

This species is known from two pins, both from Coward Springs, South Australia. The highly polished appearance, the overlapping mesonotum in the major worker and the high placement of the eyes on the head capsule in the minor worker help to distinguish this species from similar species in the M. aeneovirens group. Nothing is known of its biology.

Etymology.

Latin fulgidus ( ‘gleaming’); participle in nominative singular.