Chelaner striatifrons

My one collection of C. striatifrons, south of Shark Bay, Western Australia, came from a nest that had a small, simple entrance hole (Heterick 2001).

Identification
Heterick (2001) - A member of the bicornis group. Chelaner striatifrons is a distinctive red or orange-red species. Unlike Chelaner rufoniger, the species is monomorphic, and also has a rounded propodeum with characteristic horizontal striae girdling it. The rugosity of this species also distinguishes it from the otherwise similar Chelaner majeri.

Heterick (2009) - A large, for Chelaner, reddish species.

Distribution
NT, SA and WA.

Heterick (2001) - Although all but one of the specimens examined were taken in Western Australia, this large Chelaner species probably has a much wider distribution throughout the Eremaean region than the sparse records suggest.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  striatifrons. Monomorium striatifrons Heterick, 2001: 376, figs. 23, 53, 61, 147, 157, 168 (w.q.m.) AUSTRALIA.
 * Combination in Chelaner: Sparks et al., 2019: 233.

Worker
Holotype. HML 4.28; HL 1.52; HW 1.55; Cei 102; SL 1.08; SI 70; PW 0.84. Other. HML 4.51-5.19; HL 1.65-1.88; HW 1.65-1.85; Cel 94-102; SL 1.09-1.34; SI 67-72; PW 0.75-0.96 (21 measured).

Head. Head square or rectangular; vertex slightly concave; frons longitudinally striate with erect and suberect setae. Compound eyes elliptical; (viewed from front) compound eyes set in anterior half of head capsule; (viewed laterally) compound eyes set anterior of midline of head capsule; eye moderate, eye width 0.5-1.5x greatest width of antennal scape. Antennal segments 12; club gradually tapering and barely discernible. 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 antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes parallel straight. Venter of head capsule without elongate, basket-shaped setae. Palp formula 2,3. Maximum number of mandibular teeth and denticles: four; mandibles (viewed from front) strap-like with inner and outer edges subparallel, striate, with piliferous punctures; basal tooth enlarged, much broader than other non-apical teeth; basal angle indistinct; apical and basal mandibular margins meeting in curve.

Alitrunk. Promesonotal sculpture present in form of microreticulation and rugosity over entire promesonotum; dorsal promesonotal face evenly convex; erect and suberect promesonotal setae greater than 10; setulae absent. Mesonotal suture visible externally as faint ridge. Metanotal groove present as distinct and deeply impressed trough between promesonotum and propodeum. Propodeal sculpture present as uniform rugosity, with well defined costulae on declivitous face of propodeum; dorsal propodeal face strongly 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 absent. 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 positioned in pedicel well anteriad of petiolar node. Petiolar node conical, dorsally rounded; sculpture present; petiolar node rugose. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 1:1. Anteroventral process always absent or vestigial. Ventral lobe always absent. Height ratio of petiole to postpetiole near 1:1; height-length ratio of postpetiole near 1:1. Sculpture present in form of microreticulation. Ventral process present and distinct.

Gaster. Pilosity of first gastral tergite consisting entirely of well-spaced erect and suberect setae.

General characters. Colour of head, alitrunk, petiole, postpetiole and most of first gastral tergite red to reddish orange, rear of gaster, legs, and antennal scape brown to dark brown. Worker caste monomorphic.

Queen
HML 4.60-5.17; HL 1.50-1.67; HW 1.55-1.67; Cel 100-107; SL 1.09-1.22; SI 69-73; PW 1.14-1.29 (5 measured).

Head. Head square or rectangular; vertex slightly concave; frons longitudinally striate with combination of appressed setulae and erect and suberect setae. Compound eyes elliptical; (viewed from front) compound eyes set in anterior half of head capsule; (viewed laterally) compound eyes set anterior of midline of head capsule; eye large, eye width greater than 1.5x greatest width of antennal scape.

Alitrunk. Mesoscutum in profile evenly convex. Mesoscutal pilosity consisting of decumbent and subdecumbent setulae anteriad and erect and suberect setae posteriad; dorsal appearance of mesoscutum longitudinally striate; length-width ratio of mesoscutum and scutellum combined near 4:3. 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 strongly convex. Propodeal processes absent (propodeum smoothly rounded in profile or with slight hump at propodeal angle); lobes present as blunt flanges. Propodeal angle absent. Erect and suberect propodeal setae greater than 10; propodeal setulae absent. Propodeal spiracle lateral and nearer metanotal groove than declivitous face of propodeum.

Wing. Wing veins tubular and strongly sclerotised; vein m-cu present as an entire vein enclosing first discoidal cell; vein cu-a present.

Petiole and postpetiole. Petiolar spiracle lateral and positioned in pedicel well anteriad of petiolar node. Petiolar node tumular and inclined anteriad; sculpture present in form of microreticulation. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 1:1 to near 3:4. Anteroventral process always absent or vestigial. Height ratio of petiole to postpetiole near 1:1; height-length ratio of postpetiole near 4:3 to near 1:1. Sculpture present in form of microreticulation; ventral process present and distinct.

Gaster. Pilosity of first gastral tergite consisting entirely of erect and suberect setae.

General characters. Colour crimson to orange; katepisternum, legs and sometimes other parts of body infuscated. Brachypterous alates seen and examined. Ergatoid or worker-female intercastes not seen.

Male
HML 4.11-4.42; HL 0.98-1.09; HW 1.01-1.11; Cel 100-108; SL 0.31-0.34; SI 29-31; PW 0.98-1.24 (5 measured).

Head. Head width-mesoscutal width ratio near 1:1. Compound eyes protuberant and elliptical; (viewed laterally) compound eyes set at midline of head capsule; ocelli not turreted. Ratio of length of first funicular segment of antenna to length of second funicular segment near 1:3 to near 1:4. Maximum number of mandibular teeth and denticles: three (usually two).

Alitrunk. Mesoscutum in profile convex anteriad; thereafter flattened; dorsal appearance of mesoscutum reticulate; 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 present as an entire vein enclosing first discoidal cell; vein cu-a present.

Petiole and postpetiole. Petiolar spiracle lateral and positioned in pedicel well anteriad of petiolar node. Sculpture present; petiolar node rugose; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 3:4. Anteroventral process always absent or vestigial; ventral lobe always absent. Height-length ratio of postpetiole near 4:3 to near 1:1; sculpture present; postpetiole rugose; ventral process absent or vestigial, or present and distinct.

Gaster. Pilosity of first gastral tergite consisting entirely of well-spaced erect and suberect setae.

General characters. Colour chocolate; gaster and legs orange, coxae and antennae brown.

Type Material
Holotype. Worker (top point), Western Australia, Mount Magnet area, 15.v.1967, C. Mercovich, ANIC vial no. 66-39. Paratypes. Western Australia: 2 workers, same data as holotype (ANIC); 3 workers, no vial details, same data as holotype ; 1 queen and 2 males, ANIC vial no. 66-38, otherwise same data as holotype (ANIC); 3 workers, ANIC vial no. 66-38, otherwise same data as holotype ; 3 workers, ANIC vial no. 66-40, otherwise same data as holotype (BMNH); I worker, 30 km S “The Overlander”, 20.iii.1987, B. E. Heterick, soil, native veg., rural environ., 174/6MonBH32 (ANIC); 1 queen, Tardun, 22.v.1963, C. T. Mercovich, mallee 400ft., ANIC vial no. 66-53 (MCZ).



Etymology
Latin: “striated forehead”.

References based on Global Ant Biodiversity Informatics

 * CSIRO Collection
 * Gunawardene N.R. and J.D. Majer. 2004. Ants of the southern Carnarvon Basin, Western Australia: an investigation into patterns of association. Records of the Western Australian Museum 22: 219-239.
 * Heterick B. E. 2001. Revision of the Australian ants of the genus Monomorium (Hymenoptera: Formicidae). Invertebrate Taxonomy 15: 353-459.
 * Heterick B. E. 2009. A guide to the ants of south-western Australia. Records of the Western Australian Museum Supplement 76: 1-206.