Tetramorium bicarinatum

Tetramorium bicarinatum is one of the most successful, abundant, and widespread tramp species within the genus Tetramorium. It occurs in almost all tropical and subtropical habitats around the world, except for most of the Afrotropical, and also has been transferred to temperate countries where it can survive in constantly heated buildings (botanical gardens, zoos, etc.). The species is known to occur in most of the Oriental and Indo-Australian regions, including almost all Pacific island systems, the New World, Europe, the Malagasy region, and on several islands in the Atlantic and Indian Oceans (Hita Garcia and Fisher 2011).

Identification
Hita Garcia and Fisher (2011) - Tetramorium bicarinatum can be well identified within the T. bicarinatum group in the Malagasy region because of its distinctly sculptured mandibles, rectangular nodiform petiolar node with antero- and posterodorsal angles at about the same height, and its characteristic bicolouration.

Distribution
Worldwide throughout tropical and subtropical regions (widespread tramp species).

This taxon was described from the United States. It is also found in New Caledonia, Dominican Republic, Philippines.

Hita Garcia and Fisher (2011) - Its native range was originally thought to be in Africa by a number of authors (Creighton, 1950; Brown, 1957; Taylor & Wilson, 1961; Wilson & Taylor, 1967). Yet the species is not even native to the Afrotropical region, and is only known there from very few introductions (Bolton, 1979, 1980). It seems that the Afrotropical members of the T. bicarinatum group, all endemic to this region, have the ability to hinder the establishment of T. bicarinatum. Outside of Africa, in the Malagasy, Neotropical, and parts of the Palaearctic and Neartic regions, these T. bicarinatum group species are absent, and T. bicarinatum can set up stable populations. The situation is different in the Oriental and Indo-Australian regions because T. bicarinatum is widespread and common but the T. bicarinatum species group is also present with a number of species closely related to T. bicarinatum. This fact led Bolton (1977, 1979, 1980) to the conclusion that the native range of T. bicarinatum is most probably in South East Asia, from which it was anthropogenically transferred to the rest of its actual, immense distribution range. This view is supported by several authors (McGlynn, 1999; Deyrup, 2000; Astruc et al, 2001) and we concur with this opinion.

Malagasy region
Hita Garcia and Fisher (2011) - T. bicarinatum is almost surely not native to the Malagasy region and can be considered introduced. It is now a common species well-established in most of Eastern and Northern Madagascar, and also can be found in some tropical dry forest or gallery forest habitats in the western part of the country. It seems completely absent from the more arid Southwest and the High Plateau. In addition, T. bicarinatum can be commonly encountered on most of the surrounding islands, e.g. the Comoros, Mayotte, Seychelles, Reunion, and Mauritius.

Nomenclature

 *  bicarinatum. Myrmica bicarinata Nylander, 1846b: 1061 (w.q.) U.S.A. Forel, 1891b: 151 (m., misidentified as guineense); Wheeler, G.C. & Wheeler, J. 1954d: 449 (l., misidentified as guineense); Wheeler, W.M. 1924c: 136 (gynandromorph, misidentified as guineense). Combination in Tetramorium: Mayr, 1862: 740; Bolton, 1977: 94. Junior synonym of Formica guineensis Fabricius, 1793: 357 (now in Pheidole): Mayr, 1862: 740. Revived from synonymy and senior synonym of cariniceps (and its junior synonym kollari), modesta Smith, reticulata: Bolton, 1977: 94. [Note. The names cariniceps, kollari and reticulata had previously been incorrectly synonymised with guineensis Fabricius by Roger, 1862c: 293; modesta Smith was wrongly synonymised with guineensis by Donisthorpe, 1932c: 463.] See also: Bolton, 1979: 164; Hita Garcia & Fisher, 2011: 18.
 * cariniceps. Myrmica cariniceps Guérin-Méneville, 1852: 79 (w.) DOMINICA. Combination in Tetramorium: Roger, 1861b: 171. Senior synonym of kollari: Roger, 1861b: 171. Junior synonym of guineense: Roger, 1862c: 293; of bicarinatum: Bolton, 1977: 94.
 * kollari. Myrmica kollari Mayr, 1853c: 283 (w.q.m.) AUSTRIA. Junior synonym of cariniceps: Roger, 1861b: 171.
 * modesta. Myrmica modesta Smith, F. 1860b: 108 (w.) INDONESIA (Batjan I.). [Unresolved junior primary homonym of modesta Foerster, above.] Combination in Tetramorium: Donisthorpe, 1932c: 463. Junior synonym of guineense: Donisthorpe, 1932c: 463; of bicarinatum: Bolton, 1977: 94.
 * reticulata. Myrmica reticulata Smith, F. 1862b: 33 (w.) PANAMA. Combination in Tetramorium: Mayr, 1862: 740. Junior synonym of guineense: Roger, 1862c: 293; of bicarinatum: Bolton, 1977: 94.

Worker
Hita Garcia and Fisher (2011 ) - HL 0.760–0.910 (0.848); HW 0.655–0.810 (0.740); SL 0.510–0.625 (0.575); EL 0.185–0.220 (0.201); PW 0.480–0.580 (0.532); WL 0.940–1.120 (1.037); PSL 0.175–0.240 (0.208); PTL 0.230–0.290 (0.262); PTH 0.260–0.330 (0.299); PTW 0.235–0.300 (0.264); PPL 0.220–0.280 (0.247); PPH 0.250–0.315 (0.292); PPW 0.295–0.365 (0.329); CI 85–89 (87); SI 75–80 (78); OI 26–28 (27); PSLI 22–26 (24); PeNI 46–52 (50); LPeI 84–93 (88); DPeI 96–106 (101); PpNI 59–66 (62); LPpI 81–91 (85); DPpI 128–139 (133); PPI 120–132 (124) (23 measured).

Head distinctly longer than wide (CI 85–89). Anterior clypeal margin with distinct median impression. Frontal carinae strongly developed, ending shortly before posterior head margin. Antennal scrobes weakly developed, narrow, shallow, and posterior and ventral margins never differentiated, as long as frontal carinae. Antennal scapes of moderate length, not reaching posterior margin of head (SI 75–80). Eyes relatively large (OI 26–28), with 11 to 14 ommatidia in longest row. Mesosomal outline dorsally flat, metanotal groove absent. Propodeal spines medium-sized to long (PSLI 22–26). Propodeal lobes small, triangular, and acute. Petiolar node rectangular nodiform, anterior and posterior faces roughly parallel, anterodorsal and posterodorsal angles at about same height, in dorsal view weakly longer than wide to weakly wider than long (DPeI 96–106), in lateral view higher than long (LPeI 84–93). Postpetiole in profile roughly rounded and higher than long (LPpI 81–91), in dorsal view distinctly wider than long (DPpI 128–139). Postpetiole in profile less voluminous than petiolar node, in dorsal view always distinctly wider than petiole (PPI 120–132). Mandibles distinctly longitudinally striate. Clypeus longitudinally rugose, usually with three strong rugae. Most of head with reticulate-rugose sculpturation, area between frontal carinae from posterior clypeal margin to posterior eye margin irregularly rugose with few cross-meshes; ground sculpturation on head weak and faint. Mesosoma and waist segments reticulate-rugose without ground sculpture. Gaster with basigastral costulae on the first tergite, remainder completely unsculptured, smooth, and shiny. All dorsal surfaces of head, mesosoma, waist segments, and gaster with numerous long, standing hairs; hairs on antennal scapes and tibiae appressed to suberect. Head, mesosoma, waist segments, and legs yellowish orange to orange brown, gaster always much darker, usually dark brown to blackish brown.

Additional References
Hita Garcia, F. and B.L Fisher. 2011. The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—introduction, definition of species groups, and revision of the T. bicarinatum, T. obesum, T. sericeiventre and T. tosii species groups. Zootaxa 3039:1-72.