Melophorus latinotus 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 : 170-172

Melophorus latinotus Heterick, Castalanelli & Shattuck sp. n.

Types.

Minor worker from Eneabba region 29°24'27"S, 115°06'49"E, Western Australia, 24-28 November 2006, A. Gove/N. McCoy, Melaleuca leuropoma sandplain slope: pitfall trap 2H [JDM32-002004] (WAM). Paratypes: 2 minor workers from Eneabba region 29°41'45"S, 115°11'18"E, Western Australia, 24-28 November 2006, A. Gove/N. McCoy, Conospermum triplinerv / Eremaea beaufortioides , sandplain flat: pitfall trap 23N [JDM32-002003] (WAM); 2 minor workers with same collection data as preceding paratypes [ANIC].

Other material examined.

Western Australia: 9 kn N Yanchep (Leicester, K./McDavitt, S.).

Diagnosis.

Melophorus latinotus can be placed in the M. biroi species-group on the basis of characters of the clypeus, propodeum, mandible and palps. The species is placed in the M. biroi species-complex on the basis of a further suite of characters (viz, metatibia of major worker with only one preapical spur [except rarely in the mjobergi clade]; clypeal psammophore placed anteriorly at or just above anterior margin of clypeus in the minor worker and often in the major worker; head dorsoventrally compressed to varying degrees in the minor worker of most species with the eyes placed high on the sides; compact legs, and small body size [excluding mjobergi clade] HW of smallest minor 0.36 mm, average HW of smallest minors 0.46 mm; HW of largest known major 1.29 mm, average HW of largest majors [where known] 1.05 mm). Uniform, minute, net-like microreticulation and a transverse row of short, stout unmodified setae placed across the centre of pronotum distinguish minor workers of this rare ant from similar forms in the M. biroi species-complex. The major worker is unknown.

Minor worker description.

Head. Head square; posterior margin of head planar or weakly convex; frons matt or with weak sheen, microreticulate or microreticulate-shagreenate; pilosity of 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 around midline of head capsule; eyes elliptical or slightly reniform. In full-face view, frontal carinae distinctly concave; frontal lobes straight in front of antennal insertion. Anteromedial clypeal margin broadly and evenly convex; clypeal psammophore set below midpoint of clypeus; palp formula 6,4. Five mandibular teeth in minor worker; man dibles 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; anterior mesosoma in profile rounded anteriad, thereafter pronotum and whole of mesonotum flattened and on a higher plane than propodeum; appearance of erect pronotal setae short, (i.e., longest erect setae shorter than length of eye) and unmodified; in profile, metanotal groove a narrow but deep slit; propodeum matt or with a weak sheen and microreticulate; propodeum angulate, propodeal angle blunt; length ratio of propodeal dorsum to its declivity between 1:1 and 1:2; 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 longer (length ≥ 0.50 × height of propodeum). Petiole. In profile, petiolar node squamiform; in full-face view, shape of petiolar node uniformly rounded; node matt with indistinct microsculpture. Gaster. Gaster matt with faint, indistinct microsculpture; pilosity of first gastral tergite consisting of well-spaced, long, whitish, appressed setae with erect setae (present in at least some workers) confined to margin of the sclerite. General characters. Colour dull brown.

Measurements.

Worker (n = 2): CI 101-103; EI 26-26; EL 0.15-0.17; HL 0.54-0.59; HW 0.56-0.59; ML 0.75-0.78; MTL 0.41-0.45; PpH 0.09-0.08; PpL 0.34-0.35; SI 108-114; SL 0.60-0.68.

Comments.

There seems little doubt that this uncommon ant has a very localized distribution on the Swan Coastal Plain in WA from about Perth to south of Geraldton. Only the minor worker is known. Just two collections have been recorded; one from Eneabba and one from Yanchep National Park. The species resembles M. biroi but has a few, short, erect setae on the pronotum, and is very dull and matt in appearance with the cuticular pattern on the mesosoma a fine, reticulate mesh. No specimens were available for sequencing and there are no ecological data.

Etymology.

Latin latus ( ‘broad’) plus Latinized Greek notus (Greek notos ‘back’); adjective in the nominative singular.