Ectomomyrmex

Ectomomyrmex is restricted to Asia and Australia. They are apparently epigeic generalist predators.

Identification
Schmidt and Shattuck (2014) - Ectomomyrmex workers can be identified by the following combination of characters: head, mesosoma and petiole strongly sculptured, head usually prismatic posteriorly, mesopleuron divided by a transverse groove, and petiole with a sweeping posterior face. Ectomomyrmex workers are similar to those of some Ponera species (e.g., Ponera alpha), but Ectomomyrmex workers lack an anterior fenestra in the subpetiolar process and have two metatibial spurs and a divided mesopleuron. Ectomomyrmex is also superficially similar to Pachycondyla, but Ectomomyrmex lacks the complex metapleural gland orifice and hypopygial spines of Pachycondyla, and Pachycondyla lacks the prismatic head shape of Ectomomyrmex. Ectomomyrmex is also somewhat similar to Cryptopone and Pseudoponera, but differs from them in having strong sculpturing, larger eyes, no basal mandibular pit, a prismatic head, divided mesopleuron, slit-shaped propodeal spiracles, a sweeping posterior petiolar face, and no traction setae on the mesotibiae. Ectomomyrmex may be confused with Pseudoneoponera or Bothroponera, but Ectomomyrmex lacks the shaggy pilosity and longitudinally striate tergite A3 of Pseudoneoponera, and the large eyes, undivided mesopleuron, and block-like petiole of Bothroponera.

Distribution
Ectomomyrmex ranges across most of the Indo-Australian and Australasian regions, from India east to Japan and from northwestern China south to northern Australia (Brown, 1963).

Species richness
Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data



Biology
Schmidt and Shattuck (2014) - Very little is known about the habits of Ectomomyrmex. Anecdotal observations, and the moderately small eyes of Ectomomyrmex workers, suggest that their foraging habits are somewhat intermediate between epigeic and hypogeic. They are apparently generalist arthropod predators (Wilson, 1958c, 1959a), and Ke et al. (2008) observed that workers of Ectomomyrmex astutus were particularly fierce predators of termites in an artificial arena. Wilson (1958c) observed Ectomomyrmex aciculatus foraging diurnally on the forest floor among and under leaf litter, observed Ectomomyrmex exaratus foraging on the forest floor, and reported that E. striatulus forms small colonies (fewer than 100 workers) and nests in rotting logs. Like its close relatives Ponera and Cryptopone, workers of Ectomomyrmex apparently feign death when disturbed (Wilson, 1958c).

Nomenclature

 *  ECTOMOMYRMEX  [Ponerinae: Ponerini]
 * Ectomomyrmex Mayr, 1867a: 83. Type-species: Ectomomyrmex javanus, by subsequent designation of Bingham, 1903: 85.
 * Ectomomyrmex as subgenus of Pachycondyla: Emery, 1901a: 42; Emery, 1911d: 78; Forel, 1917: 237.
 * Ectomomyrmex as genus: Bingham, 1903: 85; Wheeler, W.M. 1922a: 648; Brown, 1963: 9; Taylor, 1987a: 26.
 * Ectomomyrmex junior synonym of Pachycondyla: Snelling, R.R. 1981: 389; Hölldobler & Wilson, 1990: 11; Brown, in Bolton, 1994: 164.
 * Ectomomyrmex revived from synonymy: Schmidt & Shattuck, 2014: 191.
 * [Ectomyrmex: incorrect subsequent spelling by Donisthorpe, 1943f: 641.]

Description
Schmidt and Shattuck (2014):

Worker
Medium to large (TL 5–12.8 mm) ants with the standard characters of Ponerini. Mandibles triangular, with up to 10 teeth on the masticatory margin and often a faint basal groove. Anterior clypeal margin convex, sometimes medially emarginate. Frontal lobes small to moderate in size. Eyes very small to small, located anterior of head midline. Head usually prismatic posteriorly, with distinct angular ridges between dorsal and lateral surfaces. Mesopleuron divided by a transverse groove. Metanotal groove obsolete or reduced to a simple suture. Propodeum broad to narrowed dorsally, with sharp posterior margins. Propodeal spiracles slit-shaped. Metapleural gland orifice sometimes with a posterior flange. Metatibial spur formula (1s, 1p). Petiole squamiform to nodiform, the scale usually much wider than long, in dorsal view with a convex anterior face and in lateral view a forward-sweeping posterior face. Gaster with a moderate girdling constriction between pre- and postsclerites of A4. Head, mesosoma and petiole deeply striate, rugoreticulate or punctate, the gaster usually finely punctate but sometimes striate (e.g. in Ectomomyrmex acutus). Head and body with abundant short pilosity and light to dense pubescence. Color black.

Queen
Similar to worker but slightly larger, winged, with ocelli, larger compound eyes, and the usual modifications of the thoracic sclerites (Ogata, 1987).

Male
See description by Ogata (1987).