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.

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.

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.

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.

Worker
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.

Male
Males are not known for this species.

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

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)