Gnamptogenys

Gnamptogenys is a group of predatory ectatommine ants found in tropical and subtropical, mesic forested areas in Southeast Asia and Australasia and from the southern United States to northern Argentina. Most species nest at ground level in rotten wood or leaf litter, but some are arboreal. Their colonies are relatively small, with at most a few hundred workers. Reproduction is generally through queens, though worker reproduction is known in some species from Southeast Asia. While many species are generalist predators, specialized diets such as millipede predation have arisen in several New World lineages. The New World species of Gnamptogenys were revised by Lattke in 1995 while the Asian and Australian species were revised by Lattke in 2004.

Identification
The forward sections of the frontal lobes and the antennal sockets are separated by the broadly rounded or triangular rearward extension of the clypeus. When viewed from above, the pronotum and mesonotum form a single, uninterrupted plate. The first segment (coxa) of the hind leg has a tooth or spine on its upper surface near the body in the vast majority of species. The node of the petiole has distinct front, top and rear faces.

While the majority of Gnamptogenys species can be diagnosed by the presence of the denticle on the metacoxal dorsum, this structure is absent in a number of species (currently 5 cases are known). An invariable autapomorphy for Gnamptogenys is the loss of the apical seta on the fore tibia. The absence of this seta will allow identification of the few species which lack the distinctive spine on the dorsum of the hind coxa.

These ants share many features with Ectatomma, Heteroponera and Rhytidoponera, but the fused pronotum and mesonotum and the spine on the coxa of the hind leg (near the body) are unique and will separate these ants from all others.

The new world species have been arranged into species groups.

Biology
Gnamptogenys are predatory ants that inhabit tropical and subtropical mesic forests. Nesting is typically at ground level in rotten wood or leaf litter. Some exceptions include species that are arboreal, a dry forest species and species that nests in sandy savannahs. Colony size tends to be, at most, in the hundreds. Queens are the reproductives in most species. Worker reproduction (gamergates) is known from a few species in Southeastern Asia. Generalist predation is the primary foraging/dietary strategy. Specialization on specific groups (millipedes, beetles, other ants) has developed in a few species.

Brown's (1993) account of predation and feeding for the species Gnamptogenys ingeborgae provides insight into how some of the species in this genus specialize on millipede prey.

Nomenclature

 *  GNAMPTOGENYS [Ectatomminae: Ectatommini]
 * Gnamptogenys Roger, 1863a: 174. Type-species: Ponera tornata, by subsequent designation of Emery, 1911d: 44.
 * [Type-species not Ectatomma concinna, unjustified subsequent designation by Wheeler, W.M. 1911f: 164; see Wheeler, W.M. 1913a: 79.]
 * Gnamptogenys subgenus of Ectatomma: Mayr, 1887: 540; Dalla Torre, 1893: 23; Emery, 1911d: 44; Wheeler, W.M. 1922a: 644; Kusnezov, 1956: 14.
 * Gnamptogenys revived status as genus and senior synonym of Alfaria (and its junior synonym Opisthoscyphus), Barbourella, Commateta, Emeryella, Holcoponera, Parectatomma, Poneracantha, Rhopalopone (and its junior synonym Mictoponera), Spaniopone, Stictoponera, Tammoteca, Wheeleripone: Brown, 1958g: 211.
 * ALFARIA [junior synonym of Gnamptogenys]
 * Alfaria Emery, 1896e: 177 (diagnosis in key). Type-species: Alfaria simulans, by original designation.
 * [Alfaria also described as new by Emery, 1896g: 41.]
 * Alfaria senior synonym of Opisthoscyphus: Brown, in Borgmeier, 1957: 115.
 * Alfaria junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * BARBOURELLA [junior synonym of Gnamptogenys]
 * Barbourella Wheeler, W.M. 1930f: 10 [as subgenus of Emeryella]. Type-species: Emeryella (Barbourella) banksi, by original designation.
 * Barbourella junior synonym of Gnamptogenys: Brown, 1958g: 212.
 * COMMATETA [junior synonym of Gnamptogenys]
 * Commateta Santschi, 1929h: 476 [as subgenus of Ectatomma]. Type-species: Ectatomma (Parectatomma) bruchi, by original designation.
 * Commateta junior synonym of Gnamptogenys: Brown, 1958g: 212.
 * EMERYELLA [junior synonym of Gnamptogenys]
 * Emeryella Forel, 1901e: 334. Type-species: Emeryella schmitti, by monotypy.
 * Emeryella junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * HOLCOPONERA [junior synonym of Gnamptogenys]
 * Holcoponera Mayr, 1887: 540 [as subgenus of Ectatomma]. Type-species: Gnamptogenys striatula, by subsequent designation of Emery, 1911d: 40.
 * Holcoponera raised to genus: Emery, 1902b: 181.
 * Holcoponera junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * MICTOPONERA [junior synonym of Gnamptogenys]
 * Mictoponera Forel, 1901e: 372 [as subgenus of Ectatomma]. Type-species: Ectatomma (Mictoponera) diehlii, by monotypy.
 * Mictoponera junior synonym of Rhopalopone: Emery, 1911d: 34.
 * Mictoponera junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * OPISTHOSCYPHUS [junior synonym of Gnamptogenys]
 * Opisthoscyphus Mann, 1922: 4. Type-species: Opisthoscyphus scabrosus (junior synonym of Alfaria minuta), by original designation.
 * Opisthoscyphus junior synonym of Alfaria: Brown, in Borgmeier, 1957: 115.
 * Opisthoscyphus junior synonym of Gnamptogenys: Brown, 1958g: 212.
 * PARECTATOMMA [junior synonym of Gnamptogenys]
 * Parectatomma Emery, 1911d: 44 [as subgenus of Ectatomma]. Type-species: Ectatomma triangulare, by original designation.
 * Parectatomma subgenus of Gnamptogenys: Forel, 1917: 236; Wheeler, W.M. 1922a: 643.
 * Parectatomma subgenus of Ectatomma: Kusnezov, 1956: 14.
 * Parectatomma junior synonym of Gnamptogenys: Brown, 1958g: 212.
 * PONERACANTHA [junior synonym of Gnamptogenys]
 * Poneracantha Emery, 1897d: 547 [as subgenus of Ectatomma]. Type-species: Ectatomma (Holcoponera) bispinosum, by original designation.
 * Poneracantha junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * RHOPALOPONE [junior synonym of Gnamptogenys]
 * Rhopalopone Emery, 1897d: 549. Type-species: Rhopalopone epinotalis, by monotypy.
 * Rhopalopone senior synonym of Mictoponera: Emery, 1911d: 34.
 * Rhopalopone junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * SPANIOPONE [junior synonym of Gnamptogenys]
 * Spaniopone Wheeler, W.M. & Mann, 1914: 11. Type-species: Spaniopone haytiana, by monotypy.
 * Spaniopone junior synonym of Gnamptogenys: Brown, 1958g: 212.
 * STICTOPONERA [junior synonym of Gnamptogenys]
 * Stictoponera Mayr, 1887: 539 [as subgenus of Ectatomma]. Type-species: Ponera coxalis, by subsequent designation of Bingham, 1903: 82.
 * Stictoponera raised to genus: Emery, 1911d: 47.
 * Stictoponera junior synonym of Gnamptogenys: Brown, 1958g: 211.
 * TAMMOTECA [junior synonym of Gnamptogenys]
 * Tammoteca Santschi, 1929h: 476 [as subgenus of Ectatomma]. Type-species: Ectatomma concinnum, by original designation.
 * Tammoteca junior synonym of Gnamptogenys: Brown, 1958g: 212.
 * WHEELERIPONE [junior synonym of Gnamptogenys]
 * Wheeleripone Mann, 1919: 282. Type-species: Wheeleripone albiclava, by original designation.
 * Wheeleripone junior synonym of Gnamptogenys: Brown, 1958g: 212.

Lattke (1995):

Generic Synopsis Worker

Sculpture consisting mostly of even parallel costae, costulae or strigae, occasionally rugose; distinct dorsomedian cephalic carinae usually absent, at most never extending more than half-way between clypeus and vertex; eyes at midlength of head or posterad, surrounded by a fine groove; lobes of frontal carinae broadly convex and partially raised, incompletely covering antennal condyles (except minuta group); funniculus filiform or incrassate, never with a distinct club; anterior clypeal border with narrow lamella of variable length; mesepisternum anteroventrally bordered by narrow lamella; pronotum unarmed, without protuberances; propodeal spiracles round or slightly ovoid, never slit-like; transverse sutures and grooves on mesosomal dorsum present or absent; mesonotum never prominently convex and bulging; anterior prosternal process bidentate; anterior mesepisternal process produced as thin triangular lobe with pointed or bluntly pointed apex; metepisternum with deep posterior cleft for petiolar insertion and continuous with open metacoxal fossae; metepisternal process located anterad of cleft and of variable development; metacoxal dorsum usually with denticle, lobe or tubercle, absent in some species; helcium protruding medianly on anterior postpetiolar face; tergite of helcium much larger than sternite; fortibial apex lacking stout moveable setae; outer border of fore tarsal comb (opposite calcar) usually with single prominent seta; meso- and metatibial spurs one or two (weakly developed), barbulate or simple; empoida lacking. In most species the pretarsal claws are bidentate on all legs, and the median tooth may vary in its position among species, and the claws may not necessarily be alike on all legs. In small species the claws may be hard to observe.

Malpighian tubule number six (Brown 1988). The genus is so diverse that characterizing it can be difficult. The following characters can be considered synapomorphies of the genus which distinguish it from its closest relatives: Ectatomma and Rhytidoponera: the single stout moveable seta on the foretibial apex and a spine or tubercle on the metacoxal dorsal surface. This former trait is lacking in some species. The following combination of characters are synapomorhic for the genus if one excludes the problem species discussed further on in the text: inconspicuous metanotum, disappearance of the median cephalic carina, lack of row of stout setae on foretarsal base opposite the strigii, leaving only one seta.