Melophorus fulvihirtus Clark

Heterick, Brian E., Castalanelli, Mark & Shattuck, Steve O., 2017, Revision of the ant genus Melophorus (Hymenoptera, Formicidae), ZooKeys 700, pp. 1-420 : 327-329

Melophorus fulvihirtus Clark

Melophorus fulvihirtus Clark 1941: 88, pl. 13, figs 19-21.

Melophorus fulvohirtus Clark 1941 (invalid (unavailable name): misspelling in literature; so Bolton 1995, et al.)

Types. Syntype major and minor workers, the minor worker headless: Patho, Victoria [MV] (examined: MV specimens T-11549, T-11550, T-11551).

Other material examined.

New South Wales: Campbelltown (Lowery, B.B. [ANIC32-900076]), Gabondery Mountains, 12 mi NW Trundle (Lowery, B.B.), Marayong, Sydney (Lowery, B.B.). South Australia: Teatree Gully (Halliday, R.B. [ANIC32-900178]). Victoria: Patho (Potter, H.A. [ANIC32-053435]), Patho (Potter, H.A.), Patho (Potter, H.A.), Patho (Potter, H.A.).

Diagnosis.

Melophorus fulvihirtus is one of only two members of the M. fulvihirtus species-group identified by having the head and mesosoma extensively covered with short, stout, peg-like bristles and, in outline, pronotum and mesonotum flattened. The metatibial apical spur is stout but very short. In M. fulvihirtus the posterior margin of the head of both major and minor workers is broadly concave, the appearance of the cuticle is matt and coriaceous, and the mandible of the minor worker is very finely striate, the individual striae being invisible under low power magnification

Minor worker description.

Head. Head quadrate (i.e., heart-shaped); posterior margin of head weakly concave; frons coriaceous; frons consisting of very short, erect, spinous setae with closely aligned, very minute, appressed setae that create a faint silvery sheen. 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 or weakly convex; frontal lobes straight in front of antennal insertion. Anteromedial clypeal margin broadly and evenly convex; clypeal psammophore set at or just above anterior clypeal margin; palp formula 6,4. Five to six 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 and coriaceous; anterior mesosoma in profile smoothly rounded anteriad, thereafter pronotum and whole of mesonotum flattened and on same plane as propodeum; appearance of erect pronotal setae short and spinous; in profile, metanotal groove a weak or vestigial furrow; propodeum matt or with a weak sheen and microreticulate; propodeum distinctly angulate, propodeal angle sharp; length ratio of propodeal dorsum to its declivity greater than 1:2; erect propodeal setae present and abundant (greater than 12); appressed propodeal setulae minute and closely aligned, creating a silvery sheen; 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 square with rounded angles; node matt and coriaceous, the peg-like setae with cuticular bases that protrude, creating a crenulate outline. Gaster. Gaster weakly shining and microreticulate; pilosity of first gastral tergite consisting of short, spinous, erect setae interspersed with massed, extremely minute, appressed setae that are visible only in certain lights. General characters. Colour tan with areas of brown infuscation.

Major worker description.

Head. Head square; posterior margin of head planar or weakly concave; cuticle of frons matt or with weak sheen, microreticulate; frons consisting of very short, erect, spinous setae with closely aligned, very minute, appressed setae creating a faint silvery sheen. Eye moderate (eye length 0.20-0.49 length of head capsule); in full-face view, midpoint of head capsule; in profile, eye set anteriad of midline of head capsule; eyes elliptical. In full-face view, frontal carinae straight, divergent posteriad; frontal lobes straight in front of antennal insertion. Anterior clypeal margin broadly and evenly convex; clypeal psammophore set below 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 weakly shining and coriaceous; anterior mesosoma in profile steeply rounded anteriad, thereafter pronotum and whole of mesonotum flattened and on a higher plane than propodeum; erect pronotal setae short and often expanded distally, at times clavate; in profile, metanotal groove shallow, broadly V- or U-shaped; propodeum shining and microreticulate, or matt or with a weak sheen and microreticulate; propodeum angulate, propodeal angle blunt; length ratio of propodeal dorsum to its declivity greater than 1:2; erect propodeal setae present and abundant (at least a dozen); 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, or square with rounded angles; node shining and faintly shagreenate-microreticulate, or matt, and microreticulate. Gaster. Gaster weakly shining with indistinct shagreenation; pilosity of first gastral tergite consisting of well-spaced, short, thick, erect setae interspersed with minute, appressed setae. General characters. Colour of foreparts orange, gaster brown.

Measurements.

Worker (n = 6): CI 116-130; EI 17-23; EL 0.24-0.40; HL 0.90-1.85; HW 1.05-2.40; ML 1.45-2.31; MTL 0.80-1.18; PpH 0.16-0.20; PpL 0.66-1.07; SI 57-126; SL 1.33-1.37.

Comments.

The appearance of M. fulvihirtus is rendered unmistakable because of a combination of short, stout, peg-like setae, deeply incised head capsule, broadly flattened femora and coriaceous cuticle. No specimens of this singular ant were available for sequencing, and, its apparently close ties with M. barbellulatus excepted, its relationship with other members of the genus is unknown. This species seems to be confined to southeastern Australia, where it has been collected in New South Wales, South Australia and Victoria. Apart from the account of the raiding habits of the ant in the paper by John Clark (1941) who described the species, label data from NSW (Gabondery Mts, 12 mi NW Trundle; Campbelltown, Sydney) also includes reference to the specimens being collected from Iridomyrmex purpureus mounds. Oddly enough, Clark does not mention what the raiding minor workers of this species were carrying, so the reader is left to guess whether their booty was eggs, larvae, pupae or provisions-a strange omission! Also rather odd is the fact that no material held in ANIC or SAMA seems to have been collected after 1974, and most specimens were taken much earlier, some from areas that are now highly urbanized. No material at all is held by QM, TERC or WAM. This leads us to wonder if populations of the ant have declined in recent decades. Certainly, populations of the putative host have not! Apart from its raiding behavior, label data are lacking for this species.