Dinoponera mutica Emery, 1901

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 : 146-147

Dinoponera mutica Emery Figs 1E, F , 12B , 13

Dinoponera grandis subsp. mutica Emery, 1901: 48 Syntype workers, BRAZIL: Mato Grosso, Germain (leg.) (MCSN) [examined] (specific locality of Rondonópolis proposed by Kempf (1971); Wheeler, G.C. and Wheeler, J. 1952: 607 (larvae.); raised to species Kempf, 1971: 378.

Worker diagnosis.

Dinoponera mutica is identified by its smooth and shiny integument with a bluish luster ( Fig. 12A ), a rounded pronotal corner lacking a tooth-like process ( Fig. 1E ), gular striations on the ventral surface of the head, long and flagellate pubescence, scape length longer than head width and petiole with even dorsal corners ( Fig. 1F ).

Description of the worker.

Measurements (mm) (n=12) TBL: 29.42-32.34 (30.99); MDL: 4.10-5.48 (4.71); HL: 5.13-6.30 (5.65); HW: 5.13-5.64 (5.39); SL: 5.43-6.05 (5.72); WL: 7.53-8.61 (8.20); PL: 2.26-2.67 (2.41); PH: 2.82-3.38 (3.17); PW: 1.54-1.90 (1.76); GL: 8.61-11.99 (10.06); HFL: 7.18-8.00 (7.60). A description of the morphology of the worker is given in Kempf (1971):

" Antennal scape remarkably longer than head width. Pubescence on front and vertex generally longer and denser than in gigantea, but lacking the golden luster on longipes. Gular face smooth and shiny, with fine, more or less distinct striation antero-laterally and antero-mesially (sometimes nearly effaced). Sides of head smooth and shining in spite of the very fine, superficial microsculpture which is reticulate-punctate. Antero-inferior corner of pronotum obtusely angulate or rounded. Pronotal disc smooth and shiny, lacking irregular fossae and wrinkles; the paired swellings rather weakly expressed. Tarsus I of hind leg decidedly longer than head width. Petiole of distinctive shape …, shorter than that of gigantea and longipes, but width-length proportion still under 0.08; anterior and posterior upper corners subequally rounded; smooth and shining; vertical sulcus on posterior face usually obsolete, present only in one Bolivian specimen. Terga I and II of gaster very indistinctly, superficially and finely reticulate-punctate yet quite smooth and shining, lacking the dense foviolae of longipes on disc where the pubescence is likewise scarce. Stridulatory file well-developed, triangular but short, visible only when acrotergite of tergum II is fully exposed."

Male.

Unknown.

Distribution.

Dinoponera mutica is found in central South America in the Brazilian states of Rondônia, Mato Grosso, Goias and Mato Grosso do Sul, in eastern Bolivia and northwest Paraguay ( Fig. 12 ).

Discussion.

Dinoponera mutica is a valid species based on our study. Dinoponera quadriceps is the closest to Dinoponera mutica in terms of morphological characters and is not synonymized in this work because of the differences stated in the diagnosis above. Males of Dinoponera mutica may provide further support for separation from Dinoponera quadriceps . Dinoponera quadriceps has a finely micro-sculptured integument which is not shiny ( Fig. 12B ), lacks gular striations and has a petiole which bulges on the dorso-anterior edge. Dinoponera longipes and Dinoponera hispida may also be confused with Dinoponera mutica but this species lacks the dense golden pubescence of the former, or the short, stiff setae and forward bulging petiole of the latter.

Material examined.

BRAZIL, MATO GROSSO DO SUL: Corumbá (1 w, MCZC); Urucum, Corumbá (3 w, 23-29.xii.1919, LACM, CUIC); RONDÔNIA: 7 km NW Costa Marques (1 w, 16.xi.1986, R Wilkerson, FSCA); Schmitt Ranch (1 w, ix.1996, R. Rogers, PALC). BOLIVIA, SANTA CRUZ: Perseverancia (1 w, 18.iii.1990, P Bettella, LACM). PARAGUAY, BOQUERÓN: Enciso (1 w, T. del Sinne, CWEM).

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 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).