Megalomyrmex silvestrii Wheeler

Longino, John T., 2010, A taxonomic review of the ant genus Megalomyrmex Forel (Hymenoptera: Formicidae) in Central America, Zootaxa 2720, pp. 35-58 : 54

Megalomyrmex silvestrii Wheeler

( Fig. 1 F)

Megalomyrmex silvestrii Wheeler,1909: 235 . Holotype worker: Cordoba, Veracruz, Mexico [MCZ] (not examined). Senior synonym of brasiliensis , langi , misionensis , sjostedti , wheeleri : Kempf & Brown, 1968: 97. Full synonymy in Kempf & Brown, 1968. See also: Brandão, 1990: 443.

Measurements. Worker: HW 0.60–0.73, HL 0.71–0.88, SL 0.83–1.08, ML 1.08–1.45 (n=30, from Brandão, 1990).

Geographic range. Widespread in the mainland Neotropics from Mexico to northern Argentina.

Biology. This species occurs in moist to wet forest habitats, from sea level to 1100 m elevation. It nests in small chambers in rotten wood or opportunistically in other small cavities in the soil. Colonies have been found in small attine nests and alone, suggesting it is a facultative predator of small Attini . Mann (1916) stated "A good series of workers were taken at Ceiba and San Juan Pueblo, nesting in the ground and in rotten logs. It is a timid species and very active when disturbed." Weber (1940) reported three collections of silvestrii (reported as wheeleri ; wheeleri synonymized with silvestrii by Kempf & Brown 1968) in nests of Cyphomyrmex costatus on Barro Colorado Island, Panama. In one nest he found a dealate queen. In a second nest he found a dealate queen and a worker. In a third nest he found 3 dealate queens and 55 workers. However, Brown (in Kempf & Brown 1968) reported finding four nests, two from Barro Colorado Island, one from Cerro Campana, Panama, and one from Santa Teresa, Brazil, that "were nesting independently of other ants so far as he could tell." Brown's two Barro Colorado nests were "inside a small clod of soil in the leaf litter," and "in a small piece of rotten wood, 10 mm deep and 15 mm wide, also contained many termites." Diniz collected isolated nests of silvestrii in Betim, MG, Brazil (reported in Brandão 1990). Kempf and Brown (1968) suggested that the species is "not so much a parasite as it is a mass-foraging predator that specializes in raiding, and sometimes occupying, the nests of small Attini ." Workers are moderately abundant in Winkler samples of forest floor litter, and workers may visit baits on the forest floor.

Material examined. BOLIVIA: Covendo, 1921–1922 (W. M. Mann); BRAZIL: Paraná: Pinhão UHE Rib. Estreito, 20 Mar 1992 (Rocha & Barreto); Sao Paulo: Mirassol, 3 Jan 1980 (Diniz & Almeida); COLOMBIA: Magdalena: Tayrona National Park, Cañaveral, 11°19'N, 073°56'W, 200 m, dry forest, 11 Aug 1985 (J. Longino); El Recuerdo, 3 km SE Minca, 11°08'N, 074°06'W, 1050 m, wet forest, 13 Aug 1985 (J. Longino); COSTA RICA: Guanacaste: Bosque Humedo, Santa Rosa Nat. Park, 10°51'N, 085°37'W, 300 m, 12 Jul 1985 (J. Longino); Heredia: La Selva Biological Station, 10°24'59"N, 084°01'12"W, 50 m, mature wet forest, 14 Jun 2004 (M Molina, D Alvarez, G Hurtado ); 7 km SW Pto. Viejo, 10°24'14"N, 084°02'22"W, 160 m, 15 Jun 2005 (M Molina/ D Alvarez/ G Hurtado); 16 km SSW Pto. Viejo, 10°19'03"N, 084°02'56"W, 500 m, 18 Apr 2006 (Marcos M, Gilberth H, Felix C); 11 km SE La Virgen, 10°20'N, 084°04'W, 500 m, montane wet forest, 14 Feb 2003 ( ALAS); 16 km SSE La Virgen, 10°16'N, 084°05'W, 1100 m, 19–22 Mar 2001 ( ALAS); Limón: Hitoy Cerere Biol. Reserve, 09°40'N, 083°02'W, 500 m, 30 Aug 1985 (J. Longino); Puntarenas: Sirena, Corcovado National Park, 08°29'N, 083°36'W, 5 m, 18 Dec 1990 (J. Longino); 13 km SSW Pto. Jimenez, 08°24'24"N, 083°19'42"W, 130 m, tropical rainforest, 10 Mar 2008 (J. Longino); 15 km SSW Pto. Jimenez, 08°24'29"N, 083°19'39"W, 170 m, mature wet forest, 7 Mar 2010 (J. Longino); GUATEMALA: Izabal: 5 km NW Morales, 15°30'44"N, 088°51'44"W, 215 m, 2º lowland rainforest, 18 May 2009 ( LLAMA); Petén: Parq. Nac. Tikal, 17°14'28"N, 089°37'20"W, 270 m, tropical moist forest, 23 May 2009 ( LLAMA); Cerro Cahuí, 17°00'08"N, 089°43'02"W, 270 m, 24 May 2009 ( LLAMA); 13 km NW Machaquilá, 16°26'47"N, 089°32'56"W, 400 m, 27 May 2009 ( LLAMA); Zacapa: 8.5 km NE Tuculután, 15°03'31"N, 089°40'35"W, 1100 m, pine oak forest, 6 Jul 2007 (M. Branstetter); HONDURAS: Atlantida, San Juan Pueblo, 15°35'N, 087°14'W (W. M. Mann); MEXICO: Chiapas: 8 km SE Salto de Agua, 17°30'53"N, 092°17'56"W, 100 m, 2º wet forest, 16 Jun 2008 (M. Branstetter); Playón de la Gloria, 16°09'33"N, 090°54'06"W, 160 m, lowland wet forest, 26 Jun 2008 ( LLAMA); 21 km SW Salto de Agua, 17°23'08"N, 092°25'41"W, 180 m, 2º wet forest, 15 Jun 2008 ( LLAMA); Lago Metzabok, 17°07'32"N, 091°37'51"W, 570 m, lowland wet forest, 6 Jun 2008 ( LLAMA); Nahá, 16°56'56"N, 091°35'42"W, 930 m, mesophil forest, 8 Jun 2008 ( LLAMA); VENEZUELA: Aragua: Ocumares de la Costa, 10°27'36"N, 067°46'35"W, 70 m, secondgrowth dry forest, 13 Aug 2008 (J. Longino).

Figures

FIGURE 1. Variation in mandibular dentition among (A) foreli, (B) symmetochus, (C) drifti, (D) incisus, (E) mondaboroides, and (F) silvestrii.