Rasopone

Rasopone is small genus of Central and South America ants known from 11 species. They are found in a wide range of habitats but are most common in rainforests where they forage in leaf litter and rotten wood.

Identification
Schmidt and Shattuck (2014) - Workers of Rasopone lack obvious autapomorphies and are superficially similar to those of a number of other genera, including Austroponera, Hypoponera, Neoponera and Pseudoponera. Separation from these and other genera of the Ponerinae is based on the following set of characters: eyes present, mandibles relatively long, mandibular pit or groove absent, mesosomal profile nearly continuous, the metanotal groove shallow or absent, metapleural gland orifice without a posterior U-shaped cuticular lip, propodeal spiracle round or ovoid, mesotibiae dorsally without abundant stout traction setae, ventral apex of the metatibia with both a large pectinate spur and a smaller simple spur, fenestra absent from the petiolar process, prora absent on anterior margin of first gastral sternite, and stridulatory organ absent from A4 pretergite.

Longino and Branstetter (2020) emended the diagnosis above from 'prora present' to ‘prora absent’, with the following explanation: There is no true prora in any caste of Rasopone or Mayaponera as defined here. In some cases there is a denticle on the sternite of the helcium that can be misinterpreted as a prora.

Schmidt and Shattuck (2014) - While similar overall, Rasopone and Neoponera belong to different genus groups and can be separated by the configuration of the metapleural gland opening. Hypoponera, while also somewhat similar, has only a single metatibial spur while two are present in Rasopone. Separation from Pseudoponera is based on the lack of a basal mandibular pit or groove and the presence of a round or ovoid propodeal spiracle. And the Australian and New Zealand genus Austroponera differs in possessing a stridulatory organ on A4 and in having a differently configured clypeus.

Distribution
Rasopone is restricted to Central and South America.

Species by Region
Number of species within biogeographic regions, along with the total number of species for each region.

Biology
Schmidt and Shattuck (2014) - While these ants are most abundant in forested habitats, they occur in a wide range of habitats, including open disturbed grassy areas, cacao and coffee plantations, mixed dry oak forest, upper montane oak forest, rocky tropical canyons, second growth rainforest, tropical montane evergreen forest, wet montane forest, primary rainforest, and cloud forest (Mackay & Mackay, 2010). Rasopone ferruginea has been collected in caves near the entrances (Reddell & Cokendolpher, 2001). Workers forage in leaf litter and rotten wood and have been collected in subterranean traps baited with Vienna sausage; they are known to be attracted to carrion (Mackay & Mackay, 2010). Most species nest in soil with some also nesting in rotten wood.

Nomenclature

 *  RASAPONE [Ponerinae: Ponerini]
 * Rasopone Schmidt & Shattuck, 2014: 208. Type-species: Ponera ferruginea, by original designation.

Description
Schmidt and Shattuck (2014):

Worker
Medium- to large-sized (TL 4–12 mm) ants with the standard characters of Ponerini.

Mandibles triangular, with roughly seven to twelve teeth, often variable size, and without a basal pit or groove. Anterior margin of clypeus variable, broadly convex or centrally concave, sometimes with a medially tooth. Frontal lobes moderately large and closely approximated. Eyes small to moderately large, located far anterior on sides of head. Mesopleuron generally entire but sometimes divided by a weak transverse impression. Metanotal groove reduced to a suture or shallow angle. Propodeum not narrowing dorsally. Metapleural gland orifice without a posterior U-shaped cuticular lip. Propodeal spiracles round or ovoid. Metatibial spur formula (1s, 1p). Petiole squamiform. Gaster with a girdling constriction between pre- and postsclerites of A4. Head and body finely punctate, sometimes with light striations on the sides of the mesosoma, and with sparse to abundant pilosity and often dense pubescence. Color variable, ferrugineous to dark brown-black.

Queen
Similar to worker but slightly larger, alate, with ocelli and larger compound eyes, and with the modifications of the thoracic sclerites that are typical of alate ponerine queens.

Male
See descriptions by Mackay & Mackay (2010) for several of the species placed here.

Larva
Described for Rasopone ferruginea (Wheeler & Wheeler, 1976).

Etymology
Rasopone is based on the geographic region of the New World where these ants occur (from the Ancient Egyptian rsw, south wind) combined with the suffix -pone, derived from the subfamily name Ponerinae.