Chelaner centralis

Common in semi-arid and arid areas.

Identification
Heterick (2001) - Monomorium centrale is a somewhat nondescript member of the rubriceps group. The morphology is quite uniform, apart from the petiolar node that varies in thickness. In a few specimens from the Porongurup Range, southwestern Australia, the node is almost cuneate.

The typical worker of Monomorium centrale bears a close superficial resemblance to workers of some M. leae populations, but can be distinguished by the deeper indentation of the anteromedial clypeal margin, and the microreticulation on the lateral panels of the promesonotum. Moreover, the head capsule in M. centrale is normally darker than the promesonotum (compared with a lighter-coloured head capsule or a head capsule concolorous with the promesonotum in most M. leae). However, specimens of M. centrale (including the holotype) from more northerly latitudes tend to a rather uniform colouration. The range of M. centrale overlaps with M. leae, but in general, M. centrale is more an ant of inland arid and semi-arid areas.

Heterick (2009) - Closely resembles Monomorium leae.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  centrale. Monomorium centrale Forel, 1910b: 28 (w.) AUSTRALIA. Heterick, 2001: 422 (q.m.). Combination in M. (Notomyrmex): Emery, 1922e: 169; in Chelaner: Ettershank, 1966: 96; in Monomorium: Taylor, 1987b: 2.

Worker
HML 1.47-2.46; HL 0.58-0.88; HW 0.46-0.80; Cel 80-92; SL 0.34-0.61; SI 75-86; PW 0.31-0.52 (26 measured).

As for the worker of Monomorium leae, but with the following apomorphies.

Head. Head square or rectangular; vertex planar. Compound eyes elliptical; (viewed from front) compound eyes set in anterior half of head capsule. Anteromedial clypeal margin emarginate, median clypeal carinae produced as pair of bluntly rounded denticles.

Alitrunk. Promesonotal sculpture present in form of striae on anterior promesonotum, and microreticulation and striolae on mesopleuron; dorsal promesonotal face convex anteriad, otherwise flattened. Metanotal groove absent to present as feebly impressed furrow between promesonotum and propodeum. Propodeal sculpture present as uniform microreticulation, with few or no striae or costulae; processes absent (propodeum angulate in profile). Propodeal angle present; length ratio of dorsal face to declivitous face near 2:1 to near 1:1; declivitous face of propodeum longitudinally concave between its lateral margins. Propodeal setulae decumbent and subdecumbent. Propodeal spiracle lateral and nearer declivitous face of propodeum than metanotal groove to lateral and about midway between metanotal groove and declivitous face of propodeum.

Petiole and postpetiole. Petiolar spiracle lateral and in anterior sector of petiolar node. Petiolar node cuboidal; sculpture present in form of microreticulation. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 4:3. Height ratio of petiole to postpetiole near 1: 1 to near 4:3; height-length ratio of postpetiole near 2:1 to near 4:3. Sculpture present in form of microreticulation.

General characters. Colour of head, alitrunk, petiole, and post-petiole russet (anterior promesonotum may be more orange in colour), gaster and appendages fulvous. Worker caste monomorphic but variable in size, with series of intercastes between largest and smallest workers (monophasic allometry).

Queen
HML 3.22-3.54; HL 0.90-1.03; HW 0.87-0.99; Cel 96-99; SL 0.62-0.74; SI 68-74; PW 0.78-0.98 (4 measured).

As for the queen of M. leae, but with the following apomorphies.

Head. Head square or rectangular; vertex slightly concave; frons striolate between frontal carinae, otherwise smooth and shining with a combination of decumbent and subdecumbent setulae and erect and suberect setae. Compound eyes elliptical; (viewed from front) compound eyes set in anterior half of head capsule to set at midpoint of each side of head capsule; (viewed laterally) compound eyes set at midline of head capsule.

Alitrunk. Mesoscutum in profile convex anteriad; thereafter flattened. Mesoscutal pilosity consisting of numerous incurved erect and suberect setae; dorsal appearance of mesoscutum smooth and shining with a few scattered piliferous pits. Axillae separated by distance less than half greatest width of scutellum. Propodeal sculpture present as uniform rugosity, with well defined costulae on declivitous face of propodeum; dorsal propodeal face sloping posteriad, with wedge-shaped flattening or shallow depression that is widest between propodeal angles. Propodeal processes present on posterior propodeal angles as small denticles or sharp flanges.

Petiole and postpetiole. Petiolar spiracle lateral and slightly anteriad of petiolar node. Petiolar node cuneate, dorsally rounded; sculpture present; petiolar node rugose. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 4:3. Anteroventral process a slender carina. Height ratio of petiole to postpetiole near 1: 1; height-length ratio of postpetiole near 3: 1. Sculpture present in form of microreticulation.

Gaster. Pilosity of first gastral tergite consisting of combination of decumbent and subdecumbent setulae and longer, erect and suberect setae.

General characters. Colour fulvous. Brachypterous alates not seen. Ergatoid or worker-female intergrades seen and examined.

Male
HML 2.61-2.82; HL 0.83-0.88; HW 0.93-1.06; CeI 112-128; SL 0.21-0.26; SI 21-25; PW 0.88-0.93 (2 measured).

As for the male of M. leae, but with the following apomorphies.

Head. Maximum number of mandibular teeth and denticles: two.

Alitrunk. Dorsal appearance of mesoscutum striolate and microreticulate; mesoscutal pilosity consisting of numerous short setae, incurved medially. Parapsidal furrows present and distinct; notauli present.

Petiole and postpetiole. Petiolar spiracle lateral and in anterior sector ofpetiolar node. Sculpture present in form of microreticulation. Anteroventral process distinct in some individuals as slender carina that tapers posteriad. Height-length ratio of postpetiole near 4:3 to near 1:1; sculpture present in form of microreticulation; ventral process absent or vestigial.

General characters. Colour chocolate; legs brown.