Chelaner longinodis

Monomorium longinode is probably the most frequently encountered of the large “Chelaner” species occurring in southwestern Australia, and is not uncommon in relict bush-land in the Perth metropolitan area. Label data and my own collecting experience indicate that this species prefers to nest in sandy soil. (Heterick 2001)

Identification
Heterick (2001) - A member of the longinode group. The length of the petiolar node can vary between populations (see description). Many worker specimens also possess a propodeal hump that is lacking in workers in the immediate vicinity of Perth. Colour is another variable feature. Specimens from localities near the south coast of Western Australia tend to be dull orange or tawny brown with heavy infuscation of the head and alitrunk. In some cases the frons is nearly black. This feature is lacking in most populations near Perth, though a series from Bushmead reveals some vestigial infuscation near the occiput. Many workers from nests in the Perth area have a crimson alitrunk and nodes, an orange head, and black, shining gaster. No collections from the area stretching from Perth to Bunbury have been seen, and these are needed to gain a better picture of the above variation.

Monomorium longinode is separable from the closely related Monomorium flavonigrum by the features listed for that species.

Distribution
Heterick (2009) - Quite common in sandy soils in the south-west corner of WA, including relictual woodland in the Perth metropolitan area.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  longinode. Monomorium longinode Heterick, 2001: 393, figs. 31, 72, 185-187 (w.m.) AUSTRALIA.

Worker
Holotype. HML 3.16; HL 1.06; HW 0.99; Cel93; SL 0.85; SI 86; PW 0.63. Others. HML 2.89-3.50; HL 0.96-1.09; HW 0.90-1.07; CeI 90-103; SL 0.79-0.93; SI 77-89; PW 0.51-0.65 (25 measured).

Head. Head square or rectangular; vertex slightly concave; frons longitudinally striate and reticulate with combination of incurved decumbent and subdecumbent setulae and erect and suberect setae. Compound eyes elliptical; (viewed from front) compound eyes set at midpoint of each side of head capsule; (viewed laterally) compound eyes set at midline of head capsule; eye moderate, eye width 0.5-1.5x greatest width of antenna) scape. Antennal segments 12; club three-segmented. Anteromedial clypeal margin emarginate, median clypeal carinae produced as pair of bluntly rounded denticles. Longest lateral anterior clypeal setae long, extending beyond dorsal margin of closed mandibles. Posteromedial clypeal margin level with posterior surface of antenna) fossae. Anterior tentorial pits situated nearer antenna) fossae than mandibular insertions. Frontal lobes parallel, sinuate. Venter of head capsule with elongate, basket-shaped setae in at least some individuals. Palp formula 2,3. Maximum number of mandibular teeth and denticles: five; mandibles (viewed from front) strap-like with inner and outer edges subparallel, striate, with piliferous punctures; basal tooth not enlarged; basal angle indistinct; apical and basal mandibular margins meeting in tooth or denticle.

Alitrunk. Promesonotal sculpture present in form of microreticulation and rugosity over entire promesonotum; dorsal promesonotal face convex anteriad, otherwise flattened; erect and suberect promesonotal setae greater than 10; setulae appressed. Mesonotal suture absent. Metanotal groove present as feebly impressed furrow between promesonotum and propodeum. Propodeal sculpture present as uniform rugosity, with well defined costulae on declivitous face of propodeum; dorsal propodeal face strongly convex to gently convex; processes absent (propodeum smoothly rounded in profile or with slight hump at propodeal angle); lobes present as blunt flanges. Propodeal angle absent; declivitous face of propodeum smoothly convex. Erect and suberect propodeal setae greater than 10; propodeal setulae decumbent and subdecumbent. Propodeal spiracle lateral and about midway between metanotal groove and declivitous face of propodeum; vestibule conspicuous through cuticle.

Petiole and postpetiole. Petiolar spiracle lateral and slightly anteriad of petiolar node. Petiolar node elongate and barrel-shaped; sculpture present; petiolar node rugose. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 1: 1 to near 3:4. Anteroventral process distinct in some individuals as slender carina that tapers posteriad. Ventral lobe always absent. Height ratio of petiole to postpetiole near 1:1 to near 4:3; height-length ratio of postpetiole near 1:1. Sculpture present in form of microreticulation, or present; postpetiole rugose. Ventral process present and distinct.

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

General characters. Colour of head amber to red, and variously infuscated with brown or black in many individuals, alitrunk, petiole and postpetiole dark crimson to amber (may be infuscated dorsally with a blackish tinge), sometimes darker in colour than head, gaster and legs amber to black. Worker caste monomorphic.

Male
HML 3.23; HL 0.78; HW 0.73; CeI 95; SL 0.31; SI 42; PW 1.03 (1 measured).

Head. Head width-mesoscutal width ratio near 4:3. Compound eyes protuberant and elliptical; (viewed laterally) compound eyes set anterior of midline of head capsule; ocelli conspicuous and turreted. Ratio of length of first funicular segment of antenna to length of second funicular segment near 1:2. Maximum number of mandibular teeth and denticles: three.

Alitrunk. Mesoscutum in profile evenly convex; dorsal appearance of mesoscutum finely microreticulate; mesoscutal pilosity consisting of numerous short setae, incurved medially. Parapsidal furrows present and distinct; notauli absent. Axillae separated by distance more than half greatest width of scutellum.

Wing. Wing veins tubular and strongly sclerotised; vein m-cu absent; vein cu-a present.

Petiole and postpetiole. Petiolar spiracle lateral and slightly anteriad of petiolar node. Sculpture present in form of microreticulation; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 3:4. Anteroventral process absent. Ventral lobe absent. Height-length ratio of postpetiole near 1:1; sculpture present in form of microreticulation; ventral process absent or vestigial.

Gaster. Pilosity of first gastral tergite consisting entirely of well-spaced appressed setulae.

General characters. Colour dark brown; gaster and legs lighter than rest of body.

Type Material
Holotype. Worker. Western Australia, Morangup Rd. (near Toodyay), 3.i.1987, B. E. Heterick, soil, native veg., rural environ., 113/6MonBH33A. Paratypes. Western Australia: 1 worker (vi.1972), 4 workers (vi.l977), Perth, John Forrest Natl Pk, Darling Range, G. H. Lowe, 94/1665, 96/1646, 96/1647, 96/1648, and 96/1649 ; 2 workers, Cannington, 9.vii.1953, R. P. McMillan, 53-1645 (WAM); 1 worker, near Perth, 1978, M. Rossbach, Al379 C34, JDM no. 502 ; 5 workers, Kings Park, Perth, 19.xii.1969, B. B. Lowery.



Etymology
Latin: “long node”.