Cardiocondyla nivalis

This species is known so far only from four islands of the Solomon group: Vella Lavela (7.76° S, 156.66° E), Guadalcanal (9.65° S, 160.21° E), Renell (11.71° S, 160.36° E) and San Cristobal (10.41° S, 161.75° E). Nothing is known of its biology.

Identification
Seifert (2022) - Worker (Figure 16, Table 3): Very small size, CS 376 µm. Head moderately long (CL/CW 1.127); with maximum CL and CW in same focal level, its posterior margin slightly concave and anterior clypeal margin strongly concave. Postocular distance large, PoOc/CL 0.440. Scape short, SL/CS 0.836. Eye rather small, EYE/CS 0.238. Frons rather narrow with short and parallel frontal carinae, FRS/CS 0.281. Mesosoma slender; dorsal profile of promesonotum and propodeum only weakly convex (nearly straight) but with a notable metanotal depression. Anterior pronotum in dorsal view rounded, without pronounced corners. Propodeal spines rather short (SP/CS 0.200), in dorsal view only very slightly diverging, in lateral view straight and their axis deviating 20° from longitudinal axis of mesosoma. Petiole in lateral view rather massive and high (PeH/CS 0.349), higher than postpetiole, with a short peduncle, a concave anterior margin and a convex dorsocaudal profile; petiole in dorsal view wide (PeW/CS 0.312), its node semiglobular and slightly longer than wide. Postpetiole moderately wide and high (PpW/CS 0.483, PpH/CS 0.327), in dorsal view much wider than long and with a concave anterior and straight to slightly convex posterior margin when these margins are adjusted to the same focal level; postpetiolar sternite flat without any anterolateral corners. Whole surface of dorsal head with circular foveolae that show a flat central tubercle, mean dFov 14.7 µm; the interspaces between foveolae about as large as foveolar diameter and finely longitudinally shagreenate (Figure 16D). Microsculpture on dorsum of mesosoma similar to that on vertex but foveolar diameter smaller; lateral mesosoma microreticulate. Petiole very finely microreticulate. Microsculpture on postpetiole still much finer, the dorsal part as a consequence slightly shiny. Basal part of 1st gaster tergite very finely microreticulate but appearing rather shiny at lower magnifications. Pubescence on 1st gaster tergite of medium length and rather dilute (PLG/CS 5.79%, sqPDG 4.94]. Gaster jet black and all remaining body parts excluding the eyes snowy white or very pale yellowish brown.

Cardiocondyla nivalis is a morphologically rather outstanding species found over a length of 600 km on a series of islands which remained separated during the Pleistocene sea level depressions.

The separation from Cardiocondyla allonivalis is based on allopatric occurrence and W.M. Mann’s description of postpetiole shape. Mann stated “… postpetiole in profile longer than high and convex above…” [43]. This indicates that the postpetiolar sternite is not bulging in contrast to the bulging bilobate structure seen in C. allonivalis.

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

Nomenclature

 * . Cardiocondyla nivalis Mann, 1919: 317 (w.) SOLOMON IS (San Cristoval I.).
 * Type-material: holotype worker.
 * Type-locality: Solomon Is: San Cristoval, Pamua, 1916 (W.M. Mann).
 * Type-depository: MCZC.
 * Status as species: Wheeler, W.M. 1935g: 20; Taylor, 1976a: 85; Bolton, 1995b: 132; Sarnat, et al. 2013: 71.
 * Distribution: Solomon Is.

Type Material
The taxon has been described from the village Pamua on the island San Cristobal (10.411° S, 161.747° E). Type specimens were not seen by Seifert (2022).

References based on Global Ant Biodiversity Informatics

 * Greenslade P.J.M. and Greenslade Penelope. 1977. Some Effects of Vegetation Cover and Disturbance on a Tropical Ant Fauna. Insectes Sociaux 24(2): 163-182
 * Mann William. 1916. The Ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology at Harvard College 63(7): 273-391
 * Mann, W.M. 1919. The ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology of Harvard College 63: 273-391
 * Taylor R. W. 1976. The ants of Rennell and Bellona Islands. Natural History of Rennell Island, British Solomon Islands 7: 73-90.
 * Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
 * Wheeler, William Morton.1935.Checklist of the Ants of Oceania.Occasional Papers 11(11): 3-56