Cardiocondyla semiargentea

So far this species is only found east of the Wallace Line in North Sulawesi from 385 to 1150 m above sea level. Its biology is unknown but should be, at least regarding male morphology and behavior, similar to the situation in the well studied, closely related Cardiocondyla argyrotricha.

Identification
Worker (Figure 11, Table 2): Smaller than Cardiocondyla argentea, with much longer head and larger postocular distance, CS 439 µm, CL/CW 1.131, PoOc/CL 0.436. Scape moderately long, SL/CS 0.830. Eye larger than in C. argentea, EYE 0.225. Anterior clypeal margin between the level of frontal carinae rather straight or slightly concave. Occipital margin slightly concave. Frontal carinae more approached than in C. argentea, FRS/CS 0.274, and immediately posterior of the FRS level slightly converging. Mesosoma extremely short; its length without neck shield only 1.04 of CL. Dorsal profile of mesosoma strongly and evenly convex. Spines of slightly longer than in C. argentea (SP/CS 0.273), acute, their bases more approached (SPBA/CS 0.362) than in C. argentea; in lateral view straight and their axis deviating by 20° from longitudinal axis of mesosoma. Petiole rather high and moderately wide (PeH/CS 0.332, PeW/CS 0.290); in lateral view in lateral view with a short peduncle, a rather high node, a concave frontal and convex caudodorsal profile; the node in dorsal view as wide or slightly wider than long. Postpetiole narrow, very low (PpW/CS 0.422, PpH/CS 0.258) and extremely short; in dorsal view with a strongly concave anterior margin; in lateral view with a semicircular ventral profile that is produced by prominent bilateral lobes of the sternite which strongly protrude compared to median level (Figure 11D). Whole surface of head and mesosoma densely foveolate-microreticulate, thus appearing at lower magnifications perfectly matt. Foveolae on vertex and dorsal pronotum with 11–15 µm diameter. Petiole microreticulate and matt; dorsal postpetiole mildly shiny and weakly microreticulate. First gaster tergite smooth and shiny without a microreticulum. Cephalic and mesosomal pubescence hairs silvery but, in contrast to C. argentea, not clearly flattened. Gastral pubescence rather long and dense (PLG/CS 5.87%, sqPDG 4.10). Strong color polymorphism. The darkest morph with whole body dark to medium brown, petiole slightly lighter with yellowish tinge. Intermediate morph with head and mesosoma dark to medium brown but spine tips, petiole, frontal laminae and clypeus contrastingly yellowish. The extremely bicolored morph has head and antennae light yellow; tibiae, tarsae, spine tips, petiole and postpetiole yellowish white; mesosoma blackish, femora and gaster blackish brown.

The strikingly bicolored morph shows no obvious structural differences to the dark and intermediate morphs and is considered here as a mutant. For separation from the closely related species C. argentea and C. argyrotricha, see Cardiocondyla argentea.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia.

Nomenclature

 * . Cardiocondyla semiargentea Seifert, 2022: 39, fig. 11 (w.) INDONESIA.

Type Material
Holotype worker labelled “INDONESIA: SULAWESI UTARA, Danau Mooat, 1200 m\nr Kotamobagu 23. x. 1985”, BMNH London; 2 worker paratypes with identic labelling, SMN Goerlitz; 1 paratype worker labelled “Indonesia_04, Sulawesi, Prov. Minasha, vic. Gunung Ambang, Donau Moaat, 0°44′ N, 124°27′ E, 800–1000 mH, 02.12.2000 543 Leg. A.Schulz”, SMN Görlitz; 2 worker paratypes labelled “INDONESIA: SULAWESI UTARA, Dumoga-Bone N.P. 9–16 May 1985”, BMNH London; 1 worker paratype with identic labelling, SMN Görlitz. 1 worker paratype labelled “INDONESIA: SULAWESI UTARA, Dumoga-Bone N.P.\Fog 5 400 m. 11.ii.85 BMNH Plot C”, BMNH London.