Megalomyrmex | |
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M. symmetochus | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hymenoptera |
Family: | Formicidae |
Subfamily: | Myrmicinae |
Tribe: | Solenopsidini |
Genus: | Megalomyrmex Forel, 1885 |
Type species | |
Megalomyrmex leoninus | |
Diversity [1] | |
44 species | |
Synonyms | |
CepobroticusWheeler, 1925 [2] Contents |
Megalomyrmex is a genus of ant in the subfamily Myrmicinae. The genus is known only from the Neotropics, where some of the species are specialized parasites or predators of Attini. [1] [3]
It is difficult to characterize morphologically. Bolton (2003) placed it in the tribe Solenopsidini, but with multiple exceptions to the diagnostic characters for the tribe. The tribal characters include a bicarinate clypeus and a median clypeal seta. Most Megalomyrmex species have a smoothly convex clypeus with no trace of the bicarinate condition, and most have abundant clypeal setae with no distinct or differentiated median seta. In Bolton's (1994) key to genera, Megalomyrmex keys in multiple places because of variability in mandibular dentition. Nevertheless, the genus has a distinctive habitus: the antenna is 12-segmented with a 3-segmented club; the general integument is smooth and shiny without coarse sculpture or dull areas; the promesonotum is evenly arched, without promesonotal groove; the propodeum is usually smoothly curved between dorsal and posterior faces, at most with blunt, broad-based tubercles, and never with spines; and the hind tibial spur is simple. In short, the workers look like a Solenopsis with Pheidole antennae. The mandibular dentition varies from a simple set of 5 similar teeth on the masticatory margin, gradually diminishing in size basally, to a condition with 2 large apical teeth followed by up to 12 small denticles. [3]
Some species have unusual alkaloids. [3] The hypothesis that alkaloids act at a distance converges with what is known for the genera Solenopsis , Monomorium and Megalomyrmex when workers release volatile venom alkaloids by waving their stingers (i.e., gaster flagging) during interspecific encounters causing their enemies to flee. [4]
It is close to Monomorium and should possibly be included in the latter. [5]
Although widespread in the Neotropics, from southern Mexico to northern Argentina, Megalomyrmex species are never abundant. They occur in low to middle elevation wet to dry forest habitats. Some species are free-living with large diffuse nests in the soil (e.g. Megalomyrmex modestus ) or small nests in dead wood (e.g. Megalomyrmex drifti ). Others are specialized social parasites or predators of Attini (e.g. Megalomyrmex adamsae , Megalomyrmex mondabora , Megalomyrmex symmetochus , Megalomyrmex wettereri ). [3]
Myrmicinae is a subfamily of ants, with about 140 extant genera; their distribution is cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes. The nests are permanent and in soil, rotting wood, under stones, or in trees.
Monomorium is a genus of ants in the subfamily Myrmicinae. As of 2013 it contains about 396 species. It is distributed around the world, with many species native to the Old World tropics. It is considered to be "one of the more important groups of ants," considering its widespread distribution, its diversity, and its variety of morphological and biological characteristics. It also includes several familiar pest species, such as the pharaoh ant and the flower ant.
Procryptocerus is a Neotropical genus of gliding ants, with the ability to "parachute" by steering their fall if they drop off of the tree they're on.
Rhopalothrix is a genus of ants in the subfamily Myrmicinae.
Megalomyrmex mondabora is a Neotropical species of ants in the subfamily Myrmicinae. Known from Costa Rica. In Costa Rica this species occurs in wet forest habitats, typically in mature rainforest. Collections are from sea level to 800 m elevation on the Atlantic slope of the Cordillera Volcanica Central, Cordillera de Talamanca, and Cordillera de Guanacaste. It is a specialized nest parasite of attines and is found most often in nests of Cyphomyrmex cornutus. It cohabits with C. cornutus in their nests, feeding on both host brood and the host's fungal symbiont.
Megalomyrmex mondaboroides is a Neotropical species of ant in the subfamily Myrmicinae. Megalomyrmex mondaboroides occurs in lowland wet forest habitats in Panama and Costa Rica. Colonies have been collected in the nests of small attines, primarily Cyphomyrmex costatus and Apterostigma goniodes. In Costa Rica a worker was collected in a Winkler sample of sifted leaf litter.
Megalomyrmex wallacei is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex wallacei can be found in Brazil, Guyana, Colombia, Costa Rica. This species occurs in mature wet forest, usually low-elevation rainforest. Brandão (2003) reports the species nesting under leaves on the forest floor, in colonies of up to 300 workers.
Megalomyrmex reina is a Neotropical species of ants in the subfamily Myrmicinae. Described in 2010, this species is known only from queens from Costa Rica. The fact that it is known only from queens is reflected in the name.
Megalomyrmex modestus is a Neotropical species of ants in the subfamily Myrmicinae. Known from Costa Rica, Panama, Colombia, Venezuela.
Megalomyrmex drifti is a Neotropical species of ants in the subfamily Myrmicinae. The species is widespread in tropical South America, north through Central America to southern Mexico.
Megalomyrmex foreli is a Neotropical species of ants in the subfamily Myrmicinae.
Megalomyrmex adamsae is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex adamsae, known from Panama, is very similar to M. symmetochus, known from Costa Rica to Panama.
Megalomyrmex incisus is a Neotropical species of ants in the subfamily Myrmicinae. The species is known from southern Mexico south to central Brazil and Peru.
Megalomyrmex miri is a Neotropical species of ants in the subfamily Myrmicinae. Known from Costa Rica. This species is known only from the type specimens and has no biological data. It is extremely similar to M. wettereri in color, size, shape, measurements, and pilosity. It differs in having a complete foraminal carina and some transverse rugosities on the anteroventral petiolar process.
Megalomyrmex wettereri is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex wettereri is known from two lowland rainforest sites: Barro Colorado Island in Panama and La Selva Biological Station in Costa Rica.
Megalomyrmex silvestrii is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex silvestrii is widespread in the mainland Neotropics from Mexico to northern Argentina. 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.
Megalomyrmex nocarina is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex nocarina occurs in mature wet forest habitats of the Atlantic slope of Costa Rica. It occurs from near sea level to 1110 m elevation. It is known exclusively as isolated workers in Winkler samples of forest floor litter.
Malagidris is a Malagasy genus of ants in the subfamily Myrmicinae. Described in 2014, the genus contains six species.
Megalomyrmex acauna is a Neotropical species of ants in the subfamily Myrmicinae. Known from Brasil and Peru. It is similar to M. leoninus-group. Its head width (HW) is 1.45—1.63 mm and head length (HL) is 1.68—1.75 mm. Its scapus length (SL) is 2.13—2.28 mm.