Daceton armigerum (Latreille)

Azorsa, Frank & Sosa-Calvo, Jeffrey, 2008, Description of a remarkable new species of ant in the genus Daceton Perty (Formicidae: Dacetini) from South America, Zootaxa 1749, pp. 27-38 : 30-32

Daceton armigerum (Latreille)

(figs. 1, 3, 5, 7, 17–19)

Formica armigera Latreille, 1802: 244 , pl. 9, fig. 58. Syntype (?) worker, Brazil (not seen).

Myrmecia cordata Fabricius, 1804: 425 . Syntypes, 2 workers, America Meridionali [South America]. (Synonymy by Roger, 1862: 290.) (seen)

Daceton armigerum (Latreille) ; Perty, 1833: 136 (combination).

Atta (?) armigera (Latreille) ; Guérin-Méneville, 1844: 421 (combination).

Daceton armigerum (Latreille) ; F. Smith, 1853: 226 (revived combination).

Worker. Measurements (mm): EL 0.44–0.87, GL 1.89–4.50, HL 1.44–4.06, HW 1.58–4.17, ML 0.79–3.32, PL 0.78–1.93, PPL 0.26-0.51, PSL 0.32-1.59, PW 1.38-4.60, SL 0.94-2.77, TL 6.91-17.8, WL 1.70–4.24. Indexes: CI 102–113, MI 55–88, PI 41–52, PSI 18–39, SI 59–73 (17 measured).

Polymorphic. Head wider than long, heart-shaped. Mandibles linear and elongate, each with an apical fork of two teeth that overlap at full closure, of which the ventral tooth is the largest. Inner (masticatory) margin of mandibles lacking any dentition but with a series of short, thick setae that differ from any other pilosity present on mandibles. Outer margin of mandibles lacking hairs completely or with very short, appressed hairs. Mandibles, in full-face view, somewhat long and narrow [(MW/ML')*100= 25–40] (fig. 23). Palp formula 5,3. Depressions, adjacent to and ventral to the mandibular insertion, deep. Clypeus without standing hairs. Pronotal humeri with acute tubercles. Lateral pronotal spines bifurcate, the anterior tips larger than the posterior ones. Metanotal groove deeply impressed. Mesosoma glabrous. Petiolar node with an anterior-lateral pair of long spines and a pair of small but sharp tubercles, located underneath the anterior-lateral spines. First gastral tergite finely reticulate and devoid of any erect or semi-erect pilosity, sometimes with very short, appressed hairs. Color of head, mesosoma, and metasoma, usually red-brown to red-yellowish, sometimes dark red-brown or rarely bicolored; petiole, postpetiole, and gaster darker than rest of body.

Range. This species is known to occur in the Terra Firma and flooded forests of Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad, and Venezuela.

The material examined conforms perfectly to the description given by Latreille (1802: 244). Daceton armigerum has been studied extensively by Wheeler & Wheeler (1954, description of larvae), Wilson (1962, ecology and behavior), Blum & Portocarrero (1966, trail pheromone and venom), Hölldobler et al. (1990, chemical communication), Moffet & Tobin (1991, physical castes), Groenenberg (1996, mandibular mode of action), and Bolton (1999, 2000, classification).

Material examined. Myrmecia cordata Fabricius , Syntypes, 2 workers, labeled: “ Essequibo [possibly Guyana], Smidt. Mus. de Sehestedt. Armigerum , Latr. [Latreille] Myrmecia cordata , worker, Fabr. [Fabricius].” Deposited in ZMUC.

Bolivia: 8 workers, Beni, Cavinas, i.1954 (W.M. Mann) [ USNM]; 4 workers, Beni, Cavinas, ii.1954 (W.M. Mann) [ USNM]; 3 workers, Beni, Huachi, ix.1954 (W.M. Mann) [ USNM]; 5 workers, Beni, Rurrenabaque, x.1954 (W.M. Mann) [ USNM]; 18 workers, Rosario, Mulford Biological Station, (L Rocagua) xi.1921 –1922, (W.M. Mann) [ USNM]. Brazil: 55 workers, Amazonas, Hwy ZF 2, Km 19, ca 60 Km N. Manaus, 02°30’S 60°15’W, 17.viii.1979, Terra Firma (T.L. Erwin et al.) [ USNM]; 2 workers, Amazonas, Rio Taruma Mirim, 20 Km NW Manaus, 02°53’S 60°07’W, 2.iii.1979 (T.L. Erwin et al.) [ USNM]; 1 worker, Amazonas, Rio Taruma Mirim, 2 Km from Rio Negro, 03°02’S 06°17’W, 29.vii.1979, Igapo black water inundation, forest canopy (T.L. Erwin et al.) [ USNM]; 9 workers, Amazonas, Itacoatiara ( Mann and Baker); 1 workers, Manaus, Reserva Ducke, 9.vi.1971, rainforest, (W.L. and D.E. Brown) [ MCZC]; 4 workers, Pará, vii.1962, B-253 (W.L. Brown) [ USNM]; 8 workers, Para, (W.M. Mann) [ USNM]; 2 workers, Mato Grosso, Tangará da Serra, 30.v.2003 (P.R. M a r l a) [ CPDC]. Colombia: 1 worker, Guaviare, R. Nukak, Cr. Moyano, Caño Cucuy. Ban 02º10’35”N 71º10’58”W, ii.1996, elev. 250 m, exc. humano (F. E s c o b a r) [IAvH]; 4 workers, Meta, PNN Sierra de la Macarena, Cabaña Cerrillo, 3º21’N 73º56’W, 21.xii.2002 to 4.i.2003, elev. 460 m,

Malaise trap, (A. Herrera and W. Villalba) [IAvH]; 3 workers, Meta, PNN Sierra de la Macarena, Caño Curia, parcela, 3º21’N 73º56’W, 9–24.ix.2003, elev. 460 m, Malaise trap, (W. Villalba) [IAvH]; 9 workers, Meta, La Macarena, 10.i.1977, in a tree (C. Kugler) [IAvH]; 3 workers, Meta, Fundación Yamato, Río Meta, Caño Miti- Miti, 1.iv.1997 (J. Madrid) [IAvH]; 3 workers, Meta, PNN Tinigua, Caño Nevera, 02º11’N 73º48’W, 23.xi.2002 to 7.i.2003, elev. 390 m, Malaise trap (C. Sanchez) [IAvH]; 1 worker, Meta, PNN Tinigua, Vda.

Bajo, 02º16’N 73º48’W, 12.xi.2002 to 5.i.2003, elev. 460 m, Malaise trap (C. Sanchez) [IAvH]; 2 workers, Meta, Villavicencio, iii.1984 (N. Ruiz) [ USNM]; 1 worker, Vichada, Cumaribo, Cgto. Santa Rita, PNN El Tuparro, 05º19’ 54”N 67º53’27”W, 10.ii.2004, elev. 135 m, mata de monte, hand collecting (I. Quintero) [IAvH]. Ecuador: 6 workers, Napo, Prov. Limoncocha, 10.vi.1977 (D.L.Vincent) [ USNM]; 1 worker, Prov. Sucumbios, Garza Cocha-Anyagu, 175 Km ESE Coca, 25.ii–2.iii.1994, (P.J. D e v r i e s) [ MCZC]. French Guiana: 2 workers, Les Nouragues, iii.2006 (A. Delean) [ CPDC]; 2 workers, Paracou, Lisière de Forêt, xi.1996 (B. Corbara et al.) [ CPDC]; 3 workers, Petit Sant Basse Vie, vi–vii.2000 (S. Durou et al.) [ CPDC]. Guyana: 1 worker, Iwokrama, Island in Essequibo River, 4° 43.890’N 58° 50.992’W, 10.iv.1996, elev. ~ 60 m, hand collecting, 1° forest, tree, (T.R. Schultz and U.G. Mueller) [ USNM]; 1 worker, Rupununi, Upper-Essequibo River, Kwatata, 3° 38.192’N 59° 27.217’W, 25.x.2002, elev. 115 m, hand collecting, bush island, (T.R. Schultz) [ USNM]. Peru: 1 worker, Loreto, Iquitos, 12 Km W, 16.ii.1984 (W. Mathis) [ USNM]; 1 worker, Loreto, Explornapo Camp on Rio Sucusari, 2 Km upstream from Rio Napo, 160 Km NE Iquitos, 20.vii.1990 (Menke and Awertschenko) [ USNM]; 5 workers, Loreto Region, 37 Km SSW of Iquitos, 04.049°S, 73.445°W, 28.viii.2004 (S. Yanoviak) [ USNM]; 7 workers, Madre de Dios, 30 Km SW Puerto Maldonado, 7.ix.1982 (J.J. Anderson) [ USNM]. Suriname: 1 worker, Temomairem Cosh Toemoeh Hoemak, 25.viii.1939 (Geijskes) [ USNM]; 1 worker, Lely Mountains, 4°16’13”N 54°44’18”W, 28.x.2005 (J. Sosa-Calvo) [ USNM]. Trinidad: 6 workers, Cumuto Village, 10–16.iv.1961, semi-deciduous forest in the Aripo savanna, (E.O. Wilson) [ MCZC]; 1 worker, 20.ii.1929, (J.G. Myers) [ USNM]. Venezuela: 3 workers, Orinoco Delta, i–ii.1935, (N.A. Weber) [ MCZC]; 1 worker, Suapure, Caura River, 2.iv.1900, (E.A. Klages) [ MCZC]; 3 workers, T.F. Amazonas, Cerro de la Neblina, Basecamp, 0°50’N 66°9’44”W, 140 m., 1–10.iii.1984 (Davis and McCabe) [ USNM].

Worker variation. Most of the within-species morphological variation in D. armigerum workers is manifested in the form of the promesonotum and, to a lesser degree, in the forms of the petiole, postpetiole, and gaster. This variation includes: (i) Lateral spines bifurcate, the posterior spine projecting upwards and curving at the tip in major workers, whereas in small or median workers this spine not curving at the tip. In small workers the posterior spine is very short, almost vestigial when viewed in profile, but conspicuous in dorsal view. (ii) Short, simple, and appressed hairs present on the first gastral tergite in some individuals from Brazil and Peru. On other workers, hairs on the first gastral segment are absent. (iii) Humeral spines, in smaller workers, vestigial or present as very low carinae. Median and larger-sized workers with humeral tubercles that are spinose or acute. (iv) The posterior pair of petiolar tubercles reduced, rounded and low in smaller workers, whereas tubercles acute in larger workers. (v) Large workers with posterior promesonotal tubercles truncate and flattened in profile. (vi) Anterior spines of petiole long and diverging with intervening space concave or with intervening space discontinuous. Anterior spines of petiole in smaller workers shorter than in other castes.