Neoponera inversa

Mackay and Mackay (2010) - This species nests in rotten cocoa pods (Heinze et al., 2001) and knot holes in cocoa trees (Kolmer and Heinze, 2000b). Dealate females were collected in May and June. Specimens in Costa Rica were collected at 9:00 am on the foliage of Byttneria aculeata [Sterculiaceae]. Queens may cooperate during colony founding (Kolmer and Heinze, 2000b, Tentschert et al., 2004), and may form polygynous mature nests (Heinze et al., 2001, 2004). The queens mate with two or more males and the queens that cooperatively form new nests are not closely related (Kellner et al., 2007). Workers will become reproductive when the nest female is removed and aggressively form dominance hierarchies (Heinze et al., 2002).

Identification
Mackay and Mackay (2010)- The strongly concave anterior face of the petiole of the worker and female of N. inversa would separate this species from the closely related Neoponera villosa, as well as from most of the other species in the genus. Mariano et al. (2000) compare the cytogenetics of N. villosa and N. inversa, and Kolmer and Heinze (2000a) recognize them as two separate species.

Neoponera curvinodis was recognized as a distinct species by Lucas et al., (2002, as Pvi2). Although we were unable to locate the type, measurement of the node in Plate 1, Figure 12 of Forel (1899), after an 8X enlargement, shows that the height of the anterior face is less than the length (0.97X), more closely matching the details of Pvi2 (Lucas et al., 2002:251). The anterior face of the petiole is also only moderately concave, characteristic of most Pvi2 (Lucas et al., 2002:251). The cuticular hydrocarbons of N. inversa and N. curvinodis are distinct (Lucas et al., 2002). Thus the two taxa with the strongly concave anterior face of the petiole are apparently distinct species, although it is nearly impossible to distinguish them.

Separation of N. inversa from N. curvinodis is difficult and the shape of the petiole is apparently one of the only morphological characteristic that will separate them. Basically N. curvinodis has a longer petiole, with a length greater than 1.3 mm when viewed in profile (measured from the anterior edge of the lateral flanges to the posterior margin, above the peduncle). The length of the petiole of N. inversa is less than 1.3 mm. The petiole of N. inversa has a more concave anterior face, making the angle at the apex strongly acute. That of N. curvinodis is generally less concave and the apex forms a less acute angle. This difference in petiolar shape results in the petiole of N. inversa appearing “taller” and the petiole of N. curvinodis appearing more robust. There is no consistent difference in the pilosity on the ventral surface of the petiole. The shape of the subpostpetiolar process differs between the two species in both the workers and females. Neoponera inversa has the area between the process and the remainder of the sternum interrupted by a constricted region, making the process or tooth appear isolated from the rest of the sternum. That of N. curvinodis is connected to the remainder of the sternum of the postpetiole by a sharp carina (or at least by a continuously raised area).

The females can be also separated by the width of the petiole; those with a wide petiole (greater than 1.5 mm) are N. curvinodis, those with a narrower petiole (less than 1.5 mm) being N. inversa.

Fernandes et al. (2014) - Worker. Propodeum punctate with sharp lateral carina; anterior face of petiole strongly concave, with sharp lateral carina.

Male: Anterior face of petiole strongly concave, dorsal region forming an apex medially; dorsopropodeum strongly striate.

The petiole of Pachycondyla inversa has a strongly curved anterior face in lateral view and the dorsum does not form an acute apex, while N. curvinodis has a more pronounced curve in the upper half of the petiole. The species also differ in size, N. inversa has SL < 2.39 mm, while that of N. curvinodis has SL > 2.63, and the scape index of N. inversa has SI < 94.65 mm, while that of N. curvinodis has SI > 104.24. According to Mackay and Mackay (2010) the taxon called Pvi2 (Pachycondyla villosa inversa 2) by Lucas et al. (2002) is currently N. curvinodis. To clarify the status of this taxon we compared N. curvinodis (original description and plate) with the type of N. inversa and we concluded that Pvi2 belongs to a new species we call N. bactronica. The male of N. inversa here described can be easily recognized by the shape of its petiole, strongly curved on the anterior face, and by a striate dorsopropodeum. Like other species of the N. foetida complex, N. inversa has a wide distribution throughout the Neotropics, occurring from Mexico to Paraguay. The species shows little variation in color, although specimens collected closer to the equator circle are more brown in color. Body size is another variable character, but is not correlated with any changes in morphological characters. Diet and age of nest are known to influence body size in many ant species.

Distribution
Central America through central South America. (Mackay and Mackay 2010)

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Panama, Paraguay, Peru, Suriname, Venezuela.

Habitat
Unknown, specimens have been collected from between 175 – 1830 meters. (Mackay and Mackay 2010)

Biology
Trindl et al. (1994) isolated and characterized 5 microsatellite loci, which are also present in the closely related Neoponera villosa.

Fernandes et al. (2014) - Neoponera inversa nests have been found in rotten cocoa pods and knot holes in cocoa trees of Theobroma cacao L. and their rotten fruits lying in the litter (Kolmer and Heinze 2000, Heinze et al. 2001). Workers have been found foraging under sheets of Byttneria aculeata Jacq. (Sterculiaceae). Several studies have indicated that colonies of N. inversa may be founded by a single queen (haplometrosis) or several (pleometrosis) and may also result in polygynous colonies (Heinze 1993, Trunzer et al. 1998, Kolmer and Heinze 2000, Heinze et al. 2001, Tentschert et al. 2001, Kolmer et al. 2002, D'ettorre et al. 2005). Pleometrosis, secondary monogyny and cannibalism were observed for the species N. inversa (I.O. Fernandes, M.L. De Oliveira & J.H.C. Delabie, unpubl.). In many ant species, newly mated queens associate with other queens to establish new colonies, independent of parentage (I.O. Fernandes, M.L. De Oliveira & J.H.C. Delabie, unpubl.).

Nomenclature

 *  inversa. Ponera inversa Smith, F. 1858b: 96 (w.) SOUTH AMERICA. Wheeler, G.C. & Wheeler, J. 1952c: 615 (l.); Mackay & Mackay, 2010: 410 (q.). Combination in Pachycondyla: Mayr, 1886c: 358; in Neoponera: Emery, 1904b: 597; in Pachycondyla: Brown, in Bolton, 1995b: 306; in Neoponera: Schmidt & Shattuck, 2014: 151. Subspecies of villosa: Emery, 1904b: 597; Mann, 1922: 7; Bolton, 1995b: 306. Raised to species: Mackay & Mackay, 2010: 409.

Worker
Fernandes et al. (2014) - (n = 164): SL: 2.30-2.38; HW: 2.43-2.50; HL: 2.60-2.78; PW: 1.70-1.78; WL: 3.96-4.30; NLd: 0.97-1.30; NWd: 1.29-1.39; NLl: 1.16-1.23; NHl: 1.00-1.17; NIl: 105.12-116.00; SI: 94.65-95.20.

Redescription of lectotype: SL: 2.39; HW: 2.45; HL: 2.67; PW: 1.72; WL: 4.23; NLd: 1.28; NWd: 1.38; NHl: 1.00; NLl: 1.15; NI: 115.00; SI: 97.55.

Head: mandibles with 14 teeth, posterior border of head slightly convex, with short erect golden hairs; eye well developed, positioned near anterior lateral margin of head; malar carina well developed and reaching eye; median portion of clypeus elevated and shiny.

Mesosoma: pronotal carina very sharp, integument finely punctate; mesonotum nearly circular and finely punctate; notopropodeal groove deep, breaking sculpture on dorsum; propodeum elevated dorsally, with rounded shape and propodeal carina well developed.

Petiole: anterior face strongly con-cave and meeting posterior face above, apex of posterior face slightly oval-shaped, sharp carina on posterolateral edges; sternopetiolar process consisting of anterior keel se-parated by carina.

Gaster: sternopostpetiolar process poorly developed.

Sculpture, pilosity and color: integument of head black finely punctate, golden pubescence and erect hairs are present on all surfaces; mandibles with row of short golden hairs near to the teeth; anterior border of the clypeus with row of short and long golden hairs; an-tennal scape covered by golden pubescence; funiculus cov-ered with golden pubescence and erect golden hairs; integument of mesosoma black, finely punctate, covered with sparse golden pubescence and long golden hairs distributed on dorsum; legs with silver and golden pubescence; anterior basitarsus and tarsus with golden pubescence on ventral surface; median and posterior tarsus black with row of golden setae in ventral surface; tarsal claws not armed with tooth; arolium brown; integument of petiole black, finely punctate, with sparse golden pubescence distributed on surface, the sides finely punctate and glossy, the dorsal surface smooth and shiny with fine punctations and erect golden hairs; integument of gaster black, finely punctate and weakly shining, erect hairs present on the dorsum; tergites and pretergites covered with sparse golden pubescence and long golden hairs; hypopygidium and pygidium strongly punctate. Appressed golden pubescence present on all surfaces and especially obvious on the head, dorsum and side of the mesosoma, posterior face of the petiole and dorsum of the gaster.

Mackay and Mackay (2010): The worker is a large (total length 13 mm) black ant with slightly lighter colored appendages. The mandible has approximately 15 teeth; the anterior border of the clypeus is indented in middle. The malar carina is well developed and extends from the anterior part of the head to the edge of the eye, which is relatively large (maximum diameter 0.75 mm) and located slightly more than one diameter from the anterior edge of the head (side view). The scapes extend about the first two funicular segments past the posterior lateral corner of the head. The carina on the pronotal shoulder is very sharp and overhangs the side of the pronotum. The mesosoma is depressed at the metanotal suture, which breaks the sculpture on the dorsum. The dorsal face of the propodeum is approximately 1½ times the length of the posterior face, the propodeal spiracle is slit-shaped. The anterior face of the petiole is strongly concave and meets the broadly rounded posterior face at the anterior edge. The petiole is relatively narrow when seen in profile (1.15 mm in the syntype). The posterior lateral edges of the petiole are sharp and nearly form carinae. The metasternal process consists of two large rounded somewhat triangular lobes.

Erect hairs are abundant on all surfaces including the scapes, the dorsum of the head, the dorsum of the mesosoma, the legs, the petiole and the gaster. Fine golden appressed pubescence is present on all surfaces and is especially obvious on the head, dorsum and side of the mesosoma, posterior face of the petiole and dorsum of the gaster. The syntype nearly lacks the pubescence on the posterior face of the petiole, which is smooth and shining.

The dorsum of the head is densely and coarsely punctate, the dorsum of the mesosoma is finely punctate and somewhat glossy and shiny, the side of the mesosoma is finely punctate and somewhat glossy, the side of the petiole is finely punctate and glossy, the posterior face is punctate and moderately glossy, the gaster is finely punctate and weakly shining.

Queen
Mackay and Mackay (2010) - The female (undescribed) is a large (total length 14 mm) black ant. The mandible has 9 large teeth with smaller teeth present between each of the large teeth. The anterior margin of the clypeus, including the medial region, is convex and rounded. The head length is 3.26 mm; the head width is 2.92 mm. The malar carina is well developed and sharp. The maximum eye diameter is 0.85 mm, which is located approximately one diameter of the anterior edge of the head. The ocelli are small, the maximum diameter of the median ocellus is 0.18 mm, located more than two diameters from the lateral ocellus (maximum diameter 0.12 mm). The scape (3.16 mm) extends approximately the first two funicular segments past the posterior lateral corner of the head. The pronotal carina is well developed and slightly overhangs the side of the pronotum. The propodeal spiracle is slit-shaped. The petiole is relatively narrow (width from above the spiracular horn to the top of the posterior peduncle is 1.40 mm). The anterior face of the petiole is strongly concave and meets the broadly rounded posterior face at a sharp anterior angle. The subpetiolar process consists of a broad lobe with a tiny angle anteriorly, the process gradually diminishing in thickness posteriorly. The anterior face of the postpetiole is slightly concave and meets the dorsal face and nearly a right angle. The stridulatory file is well developed and the arolia are present between the tarsal claws.

Erect hairs are present on most surfaces, including the mandibles, clypeus, sides of the head, posterior margin, dorsal and ventral surfaces of the head, shaft of the scape, dorsum of the mesosoma, dorsum of the petiole, all surfaces of the gaster and all parts of the legs. Appressed golden pubescence is present on all surfaces and is especially noticeable on the head, dorsum of the mesosoma, the petiole and the gaster.

The mandibles are finely striate and weakly shining. The head and mesosoma are finely punctate with most surfaces weakly shining, the side of the pronotum and the mesopleuron are moderately shining, the posterior face of the petiole is moderately shining and the gaster is shining but the surface is difficult to see due to the abundant appressed golden pubescence.

Fernandes et al. (2014) - (n = 22): SL: 2.50-2.60; HW: 2.73-2.85; HL: 2.93-3.01; PW: 2.20-2.29; WL: 4.63-4.74; NLd: 1.09-1.12; NWd: 1.55-1.61; NLl: 1.30-1.38; NHl: 1.38-1.42; NIl: 94.20-97.18; SI: 91.22-91.57.

Male
Fernandes et al. (2014) - (n = 15): HW: 1.92-2.01; HL: 1.50-1.56; PW: 1.60-1.65; WL: 4.01-4.09; NLd: 0.65-0.70; NWd: 0.80-0.84; NHl: 0.78-0.80; NLl: 0.85-0.90; NIl: 108.97-112.50.

Head: mandibles poorly developed; median region of clypeus convex and punctate.

Mesosoma: pronotum with swelling at shoulder and pronotal carina not developed; Mayrian sutures Y-shaped, not reaching scutellum in dorsal view; axial region concave and covered by oblique striae; dorso-propodeum strongly striate and slightly concave posteriorly.

Petiole: dorsal face with apex con-cave; anterior face strongly concave, and sides with fine carina; sternopetiolar process well developed forming anterior projection.

Gaster: sternopostpetiolar process consisting of projection without keels.

Genitalia: as the diagnosis for N. foetida complex (genitalia dissected on dried specimens).

Sculpture, pilosity and color: integument of head black, with fine punctations, and surface covered with long golden and silver hairs; mandibles with basodorsal area white; palpal segment covered by silver and golden sparse pubescence; silver and golden pubescence near the eyes, antennae and clypeus; integument of mesosoma black and punctate, with surface covered by golden and silver pubescence; wings light brown and shiny; legs black, covered with golden and silver pubescence; median and posterior tibia with golden pubescence on surface; anterior, median and posterior basitarsi and tarsi brown with dense golden pubescence in ventral region; median and posterior tarsi brown with row of golden setae on ventral surface; tarsal claws with median tooth and golden pubes-cence; arolium brown; integument of petiole black, with the dorsal face shiny and with long silver hairs; integument of gaster black finely punctate; tergum and sternum covered by golden and silver pubescence and long silver hairs; erect golden hairs present on head, mesosoma, petiole and gaster. Appressed silver and golden pubescence present in all surfaces.

Type Material
Fernandes et al. (2014) - Lectotype by present designation: worker, labeled “S. Amer. [Ecuador] Napo”. We were informed by the Museum that the other syntype is presumedly lost.

Mackay and Mackay (2010) - Ecuador: Napo. 1 syntype worker seen,, second syntype worker is Neoponera villosa

Ponera inversa

Two worker syntypes in. Labelled “S. Amer. Napo. 51/70.” Acc. Reg.: “1851 no. 70 (July 24). S. America (Napo River). Purchased of Mr Stevens.” One syntype, labelled as type of inversa, fits the original description; the other matches the note on “var.” given by Smith.

Etymology
The name of this species is based on the Latin word inversus, meaning turned upside down, referring to the shape of the anterior face of the petiole. (Mackay and Mackay 2010)