Dinoponera gigantea (Perty)

Lenhart, Paul A., Dash, Shawn T. & Mackay, William P., 2013, A revision of the giant Amazonian ants of the genus Dinoponera (Hymenoptera, Formicidae), Journal of Hymenoptera Research 31, pp. 119-164 : 137-139

Dinoponera gigantea (Perty) Figs 1D , 4A, F, K , 5C , 9C , 10C , 11B, C

Ponera gigantea Perty, 1833: 135, pl. 27, Fig. 3. (worker) BRAZIL: Amazonas, Rio Negro [type not found]; Kempf, 1971: 372 (male); combination in Dinoponera , Roger, 1861:38.

Ponera grandis Guérin-Méneville, 1838: 206 (worker) [type not found]; combination in Dinoponera , Roger, 1861:38; junior synonym of gigantea: Roger, 1861: 38; Kempf, 1971:371. Emery, 1911: 219 (male); Wheeler, G.C. and Wheeler, J. 1985: 387 (larvae).

Worker diagnosis.

Dinoponera gigantea can be distinguished from other Dinoponera species by the following combination of character states: antero-inferior corner of pronotum with distinct tooth-like process ( Fig. 1D ); integument finely micro-sculptured and not shiny ( Fig. 12B ); drab pilosity notably dense, long and flagellate; scape length longer than head width; total body length over 30 mm. Dinoponera gigantea is the largest species in the genus reaching up to 3.6 cm total body length. Dinoponera gigantea can be separated from all but two species by the presence of a tooth-like process on the antero-inferior corner of the pronotum. Dinoponera lucida and Dinoponera australis have a tooth-like process on the pronotum, but are smaller (usually less than 30 mm). In addition Dinoponera lucida has a shiny integument and Dinoponera australis lacks the long, flagellate pubescence.

Description of the worker.

Measurements (mm) (n=15) TBL: 31.62-36.02 (34.34); MDL: 4.59-5.35 (4.92); HL: 5.89-6.65 (6.31); HW: 5.74-6.27 (6.00); SL: 5.95-6.43 (6.30); WL: 8.71-9.94 (9.35); PL: 2.72-3.06 (2.81); PH: 3.08-3.67 (3.59); PW: 1.85-2.07 (1.98); GL: 9.43-12.24 (10.94); HFL: 8.10-9.3 (8.74). A description of the external morphology of the worker is given in Kempf (1971):

" Length of scape exceeding maximum width of head. Pubescence on front of head quite dense yet inconspicuous, not concealing the integument. Gular (ventral) surface of head reticulate-punctate throughout, very finely striate in front, the striae strongly converging mesad toward the anterior border. Sides of head reticulate-punctate, subopaque. Antero-inferior corner of pronotum dentate. Pronotal disc reticulate-punctate, subopaque, the paired swellings rather inconspicuous, but the median impression between swellings distinct, integument irregularly wrinkled. Tarsus I of hind leg longer than maximum head length. Petiole reticulate-punctate and subopaque, rectangular in profile, the anterior surface straight to slightly concave; the anterior upper corner more narrowly, the posterior corner more broadly rounded; posterior surface with the vertical sulcus always distinct; in dorsal view the petiole is decidedly longer than broad, width-length proportion below 0.80. Terga I and II of gaster opaque, sharply reticulate-punctate, densely foveolate (from each foveola arises a short decumbent hair), with scattered, bristle bearing, larger pints. The appressed pubescence, although inconspicuous, is densely spread over the entire terga, stridulatory file on acrotergite (portion of tergum that is normally concealed under the overlapping preceding tergum) of tergum II short, narrow, inconspicuous, not crossing beyond anterior half of acrotergite (hence not easily seen if entire acrotergite is not exposed)."

Male diagnosis.

Males of this species are easily recognized by their funiculus which is covered in long standing setae ( Fig. 4F ), shiny dark reddish brown integument and the combination of a long pygidial spine ( Fig. 4K ), volsella with two basal teeth, lobed end of digitus volsellaris ( Fig. 10C ) and deep concavity on the side of the penis valve of the aedeagus ( Fig. 11C ).

Description of the male.

A description of the external morphology of the male is given in Kempf (1971). Measurements done by Kempf (1971) are included as only one male Dinoponera gigantea was examined by us while the measurements of Kempf (1971) most likely represent the means of the four males examined in that study:

" Measurements in millimeters: total length 22.0; maximum length of head capsule 2.48; maximum width of head (eyes included) 3.10; maximum diameter of eyes 1.86; scape length 0.93; length of funicular articles I: 0.21, II: 1.86; Weber’s length of thorax 7.12; hind femur length 5.57; hind tarsus I length 5.38; petiole length 2.16, width 1.24, height 1.76; tergum I of gaster length 3.09, width 2.88; fore wing length 15.6; hind wing length 12.15. Chestnut brown, smooth and shining except funiculi, clypeus, front, tibiae and tarsi which are finely punctuate to reticulate-punctate; terga III and following of gaster weakly, superficially and finely reticulate. The entire insect covered with long, subdecumbent, silky pubescence, except funiculi where the pubescence is minute. Standing hairs long and abundant on body, lacking on mid-dorsum of terga II-V of gaster; long hairs on scapes rather numerous, length not much longer than twice the diameter of scape … Anterior border of labrum rounded, not visibly excised … Pygidial spine long and well developed. Parameres (gonostyli) of genitalia in side-view narrow and spear-pointed … Hypopygidium (subgenital plate of subandrium) apically rounded … "

Description of male genitalia.

Basal ring with wide dorso-anterior loop structures, dorsal depression on basal ring posterior to cleft between dorso-anterior loops, ridge extending from anterior of depression to center; parameres long, narrow, rounded spade-shape, emarginated ventro-basal edge ( Fig. 9C ); volsella with finger-like cuspis volsellaris and broad cusp-like digitus volsellaris, cuspis volsellaris with pointed end, flange extending on dorsal edge, digitus volsellaris with numerous small circular bumps, lobe on postero-dorsal edge, 2 teeth on medial ventro-basal corner of volsella, posterior tooth with lobe on posterior edge; penis valve of aedeagus with lateral arm of apodeme at anterior border, deep, wide, ventral concavity under ridge at base of apodeme, distal edge of valve wedge-shaped, proximal ventral edge of valve ending in tooth descending at roughly 45°, ventral edge with large laterally curved lip, serrated edge ( Fig. 11C ), serrations facing laterally on either side of aedeagus in dorsal view (similar to penis valve in Fig. 8A ).

Distribution.

Dinoponera gigantea has been found on the coast of Guyana, in the Brazilian states of Amazonas, Pará including Marajo Island, Mato Grosso and Maranhão as well as the Loreto Province in Perú. Dinoponera gigantea is reported to be common in un-flooded forests in the vicinity of Belém, Pará ( Kempf 1971, Overal 1980) ( Fig. 13 ). It is probable that Dinoponera gigantea is found in French Guyana, Surinam, Venezuela and southeastern Colombia because these regions are adjacent to known Dinoponera gigantea localities and have similar lowland rainforest habitat. However, no specimens from these nations are known to us, perhaps as a result of a lack of sampling or the range is absent from Colombia and southwestern Venezuela.

A record from Rio de Janeiro (from the CASC) is puzzling as it is disjunct from the known range of Dinoponera gigantea . The most southeastern locality for Dinoponera gigantea is over 1,480 km to the nearest portion of the state of Rio de Janeiro. In addition, Rio de Janeiro is in a well collected area where no other Dinoponera have been found. The label reads 'R.d.Janeiro, Brazil, D. Davis’ and the specimen agrees in all morphological characters with Dinoponera gigantea . This locality is omitted from the species’ range map ( Fig. 13 ) because of its questionable nature. If other collections can validate this locality it would mean a significant range extension for Dinoponera gigantea .

Discussion.

Dinoponera gigantea is a valid species with a distinct suite of morphological characters listed in the diagnosis above. The validity of Dinoponera gigantea is strengthened by range overlaps with Dinoponera longipes and actual sympatry with Dinoponera hispida , both with no integration of morphological characters.

Material examined.

BRAZIL, PARÁ: Belém (6 w, v.1924, FX Williams, LACM, 7 w, vi.1924, FX Williams, LACM, USNM, 1 w, i.1938, GN Wolcott and LF Martorell, USNM, 1 w, 19.ix.1943, MCZC, 1 w, vii.1961, WA Burk, LACM, 1 w, 17.iii.1964, CE and ES Ross, CASC, 1 w, 16.ii.1975, ES Ross, CASC, 1 m, 21.vii.1979, JO Schmidt, LACM); Belém APEG Forest flight trap (1 w, 29.vii-6.viii.1974, DG Young, FSCA); Braganza (1 w, HB Merrill, USNM); Jabaty (1 w, v.1924, JF Illigworth, LACM); Marajo Island (3 w, viii-x.1907, HB Merril,FMNH); Mocajuba (1 w, 9.xii.1926, EG Holt, USNM); Peixe Boi (1 w, viii-x.1907, HB Merrill, FMNH); Río Guamá nr. Belém (20 w, 10.xii.1976, CL Hogue, LACM); Tucuruí Margem esq. (1 w, 16.iii.1979, WL Overal, LACM); Utinga tract nr. Belém (1 w, 2.viii.1962, PF Darlington, MCZC); Souza (2 w, but the 16.ix.1920, LACM, AMNH); locality not specified (1 w, HB Merrill, LACM); locality not specified (2 w, 1954, WM Mann, LACM, USNM), 4 w, Baker, MCZC, CUIC, USNM, 4 w, Thayer Expedition, AMNH, 1 w, G Franch, AMNH); RIO DE JANEIRO: locality not specified (1 w, D Davis, CASC); State and locality not specified (1 w, HH Smith and T Pergande, USNM). GUYANA, CUYUNI-MAZARUNI: Dist. Bartica Kalacoon (1 w, 1916, AMNH).

Figures

Figure 1. Features of Dinoponera workers. A Head, frontal view B-C Occiput of head, oblique antero-lateral view D-E Pronotum, lateral view F-H Petiole, lateral view. A-B Dinoponera longipes C Dinoponera hispida D Dinoponera gigantea. E-F Dinoponera mutica G Dinoponera hispida H Dinoponera lucida.

Figure 4. Features of Dinoponera males. A-E Head, frontal view F-J Right scape, first and second funicular segments, frontal view K-O Pygidial spine, dorsal view A, F, K Dinoponera gigantea B, G, L Dinoponera quadriceps C, H, M Dinoponera longipes D, I, N Dinoponera snellingi E, J, O Dinoponera australis.

Figure 5. Wings of known males. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 8. Dinoponera longipes male genitalia. A dorsal view B lateral view C ventral view.

Figure 9. Dinoponera rightbasiparamere / paramere of known males, lateral view. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 10. Dinoponera rightvolsella of known males, lateral view. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 11. Dinoponera rightpenis valves from the aedeagus of known males. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 12. Worker head, oblique antero-lateral view illustrating microsculpturing difference. A Dinoponera mutica (this smooth integument type is also found in Dinoponera lucida, Dinoponera longipes and Dinoponera hispida) B Dinoponera quadriceps (this rough integument type is also found in Dinoponera gigantea and Dinoponera australis).

Figure 13. Distribution map of Dinoponera species. Symbols in black are records added by this study; open symbols are from literature sources (Kempf 1971, 1975, Araujo et al. 1990, Peeters et al. 1999, Monnin and Peeters 1999, Fourcassie and Oliviera 2002, Monnin et al. 2003, Mariano et al. 2004, Araujo and Rodriques 2006, Marques-Silva et al. 2006).