Cardiocondyla nuda

Once thought to be a cosmopolitan tramp species, revisionary work has shown the range of this species is restricted to the tropical and subtropical Pacific region.

Identification
A member of the Cardiocondyla nuda group.

Distribution
In Australia it is primarily found along the eastern and northern coastal regions, in Polynesia east to 170 W, and in New Guinea (Seifert 2008).

Distribution based on Regional Taxon Lists
Australasian Region: Australia, Norfolk Island. Indo-Australian Region: Cook Islands, Fiji, Hawaii, Kiribati, Micronesia (Federated States of), New Guinea, Niue, Pitcairn, Solomon Islands, Tokelau, Tonga, Vanuatu, Wallis and Futuna Islands. Neotropical Region: Galapagos Islands, Mexico, Puerto Rico, Puerto Rico. Oriental Region: Bangladesh, India, Nicobar Island, Thailand, Vietnam. Palaearctic Region: Afghanistan, China, Israel, Japan, Republic of Korea.

Biology
In Australia this species is found in a range of habitats from natural to urban, and from coastal dunes and grasslands to rainforest. It prefers areas with annual rainfall > 1000 mm.

Nomenclature

 *  nuda. Leptothorax nudus Mayr, 1866a: 508 (w.) FIJI IS. Emery, 1897c: 588 (q. ergatoid m.); Wheeler, G.C. & Wheeler, J. 1973a: 27 (l.); Imai, et al. 1984: 6 (k.). Combination in Cardiocondyla: Forel, 1881: 6. Current subspecies: nominal plus sculptinodis. See also: Seifert, 2003a: 245.

Taxonomic Notes
Seifert (2003) - In agreement with the type localities given in Mayr's description the type specimen from Ovalau / Fijis was designated as lectotype. Because of misidentifications, C. nuda has been erroneously termed in the past as cosmopolitan tramp species. Instead, it seems to be restricted to the tropical and subtropical Pacific region. Investigation of authentic material showed that Palaearctic "C. nuda" (sensu PISARSKI 1967, BOLTON 1982, HEINZE & al.1993) turned out to be Cardiocondyla mauritanica while Japanese-Pacific "C. nuda" (TERAYAMA & al. 1992, TERAYAMA 1999) were Cardiocondyla kagutsuchi. Cosmopolitan C. mauritanica and Indomalayan-West Pacific C. kagutsuchi differ from Australasian-Polynesian C. nuda in particular by the wider head, the smaller postocular index, the shorter spines, the lower waist segments, and the larger ratio PEH/PPH. Furthermore, the microreticulum on lateral mesosoma and petiole is less deeply sculptured than in C. nuda, in which it is relatively coarse, giving a perfectly dull surface impression at magnifications < 60x.

Subsequently, Seifert (2008) published revisionary work that separated C. nuda from C. atalanta.

Worker
Seifert (2003) - Small size, CS 468. Head elongated, CL/CW 1.224. Postocular head parallel-sided and very long, PoOc/CL 0.469. Scape of medium length, SL/CW 0.802. Occipital margin straight or slightly concave. Frontal laminae converging immediately caudal of FRS level, FL/FR in lectotype 1.095. Eyes relatively small, EYE 0.233. Foveolae on vertex in dense honey-comb arrangement, deeply impressed, with 17 - 20 µm diameter, and usually with inner corona. Frontal laminae and clypeus with few longitudinal rugulae. Whole mesosoma and lateral petiole with strong microreticulum having mesh diameters of 5 - 13 µm (smallest on petiole sides). Metanotal groove more or less shallow. Spines longer and more erect than in Cardiocondyla mauritanica and rather acute. Postpetiole in dorsal view usually with angulate-convex sides and roughly hexagonal; sides sometimes simply convex, without angular component; bulging postpetiolar sternite resulting in large PPH that is frequently larger than PEH, PEH/PPH 1.009 ± 0.026 [0.964, 1.060]. Surface of first gaster tergite shining and with very delicate microreticulum. Whole head and mesosoma of type specimen concolorous dark brown, gaster blackish brown. Lighter specimens with yellowish brown mesosomas and medium brown heads frequently occur throughout the Pacific region. For morphometric data of 34 workers see Tab. 9.

Queen
Seifert (2003) - Rather small, CS 521. Head much elongated, CL/CW 1.203. Postocular head parallel-sided and very long, PoOc/CL 0.458. Occipital margin straight or slightly concave. Foveolae on vertex in dense honey-comb arrangement, deeply impressed, with 19 -20 µm diameter, and with inner corona. Frontal laminae, clypeus, and small median stripe on vertex longitudinally carinulate-rugulose. Whole mesosoma and lateral petiole with very strong reticulum (or foveolate without interspaces). Spines short but acute. Postpetiole relatively narrow, dorsal aspect with concave anterior margin and angulate-convex sides, only slightly lower than petiole, PEH/PPH 1.061 ± 0.022 [1.028, 1.096]. Whole body concolorous dark brown. For morphometric data of 10 gynes see Tab. 17.

Male
Emery, (1897c) described the ergatoid male.