Cardiocondyla excavata

The only known collection of this species is from a nest found in a log at the margin of a mixed oak forest in Papua New Guinea.

Identification
Worker (Figure 19, Table 4): Medium-sized, CS 491 µm. Head distinctly shorter than in Cardiocondyla wheeleri, CL/CW 1.107; with head adjusted in measuring position for CL, its posterior margin straight to slightly concave and median third of anterior clypeal margin in contrast to C. wheeleri deeply concave; in caudodorsal view, the maximum depth of clypeal concavity is 2.9–3.3% CL. Postocular distance large, PoOc/CL 0.445. Scape rather long, SL/CS 0.866. Eye larger than in C. wheeleri, EYE/CS 0.238. Frons narrow (FRS/CS 0.277), frontal carinae immediately caudal of the FRS level parallel or slightly converging. Metanotal depression shallower than in C. wheeleri (MGr/CS 1.75%), dorsal profile of promesonotum and propodeum more linear than in C. wheeleri. Pronotal corners in dorsal view prominent, but blunt and forming an angle of about 90°. Dorsal plane of mesosoma rather continuously narrowing from pronotal corners caudal to metanotal groove; there is no or only a weak convexity at the mesonotal level. Propodeal spines strong but shorter than in C. wheeleri and their bases more approached (SP/CS 0.380, SPBA/CS 0.346), in lateral view downcurved with their mean orientation deviating by about 15° from longitudinal mesosomal axis. Petiole rather high (PeH/CS 0.336); in lateral view with a very short peduncle, a weakly concave frontal and broadly convex dorsal profile, in dorsal view narrower than in C. wheeleri, PeW/CS 0.257, the node longer than wide. Postpetiole less broad than in C. wheeleri, PpW/CS 0.536; in dorsal view, when both margins are adjusted to same focal level, with semicircularly rounded sides and strongly concave anterior and straight posterior margin; in lateral view much lower than petiole (PpH/CS 0.256), its sternite shallowly convex and without any prominent structures. Whole vertex with bicoronate foveolae of 16–18 µm diameter, the interspaces as large or smaller than foveolar diameter and with rather prominent reticulate microsculpture. Dorsal mesosoma reticulate, with scattered bicoronate foveolae, lateral mesosoma reticulate. Petiole matt, microreticulate. Postpetiole in dorsal view shiny and very delicately microreticulate. First gaster tergite shiny, on whole surface very delicately microreticulate. Tergite pubescence short and dilute (PLG/CS 4.68%, sqPDG 5.80). Whole body with exception of the dark brown gaster yellowish.

The strongly concave clypeus, the shorter head, the larger eye and the narrower waist segments allow to hypothesize Cardiocondyla excavata as heterospecific from Cardiocondyla wheeleri. There is probably some geographic isolation as the type localities are mountain regions separated by a deep river valley.

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

Nomenclature

 * . Cardiocondyla excavata Seifert, 2022: 49, fig. 19 (w.) PAPUA NEW GUINEA.

Type Material
Holotype and two paratype worker on separate pins, both labelled “PNG: 6.33° S, 145.86° E, 1670 m, Kainantu-4.8 km S, edge of mixed oak forest, in log, A.G.E. Emerson 1963.01.04”; depository SMN Görlitz.