Content uploaded by Jeffrey Sosa-Calvo
Author content
All content in this area was uploaded by Jeffrey Sosa-Calvo on Mar 18, 2015
Content may be subject to copyright.
Accepted by J. Longino: 24 Feb. 2008; published: 14 Apr. 2008 27
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Copyright © 2008 · Magnolia Press
Zootaxa 1749: 27–38 (2008)
www.mapress.com/zootaxa/
Description of a remarkable new species of ant in the genus Daceton Perty
(Formicidae: Dacetini) from South America
FRANK AZORSA1 & JEFFREY SOSA-CALVO2,3,4
1Departmento de Entomología, Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Apartado Postal 14-0434,
Lima 14-Perú. E-mail: frankazorsa@gmail.com
2Maryland Center for Systematic Entomology, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, Col-
lege Park, Maryland 20742.
3Department of Entomology, National Museum of Natural History, Smithsonian Institution, POB 37012, NHB, CE518, MRC 188;
Washington, D.C. 20013-7012; E-mail: sossajef@si.edu
4Corresponding author
Abstract
A remarkable new species in the ant genus Daceton, which has remained monotypic for 205 years, is described from
Brazil and Peru. The new species, Daceton boltoni sp. nov., is similar to its sister species, D. armigerum, but differs from
it mainly in the form of the pronotal lateral spines and in the pilosity of the first gastral segment. The taxonomic history
and biology of the genus is reviewed.
Key words: Ants, Brazil, Daceton armigerum, D. boltoni, Myrmicinae, Peru
Resumen
Una nueva especie de hormiga en el género Daceton, el cual ha permanecido monotípico por 205 años, se describe de
Brasil y Perú. La nueva specie, Daceton boltoni sp. nov., es similar a D. armigerum, pero difiere de ésta, principalmente,
en la forma de las espinas pronotales y en la pilosidad en el dorso del primer segmento del gaster. Una revisión de la his-
toria taxonómica y biología del género es presentada.
Palabras clave: Brasil, Daceton armigerum, D. boltoni, hormigas, Myrmicinae, Perú
Introduction
The monotypic ant genus Daceton Perty (Myrmicinae: Dacetini), and its hitherto known sole species D.
armigerum (Latreille), is restricted to South American rainforests (Kempf 1972, Fernández & Sendoya 2004,
Bolton et. al. 2007). In this region, Daceton and the larger species of the genus Cephalotes Latreille are argu-
ably the most morphologically striking arboreal ants. Daceton usually nests in cavities in the branches and
trunks of trees previously bored by beetles and other insects. Blum and Portocarrero (1966) and Moffet and
Tobin (1991) state that colonies of D. armigerum contain up to 2500 individuals, whereas Wilson (1962) and
Hölldobler & Wilson (1990) estimate that colonies contain between 5000 to 10000 workers. Daceton
armigerum has a complex continuously polymorphic caste system, in which smaller workers nurse the brood
and larger workers hunt, dismember prey items, and defend the nest (Wilson 1962; Oster & Wilson 1978;
Hölldobler & Wilson 1990). Wilson (1962) reports that workers of this highly predaceous myrmicine ant hunt
AZORSA & SOSA-CALVO
28 · Zootaxa 1749 © 2008 Magnolia Press
individually for a variety of live insects, including flies, grasshoppers, larvae and adults of moths and beetles,
and fulgorids. In addition, some workers have been observed tending coccids (Bodkin in Crawley 1916;
Brown & Wilson 1960; Wilson 1962). (Refer to Wilson [1962] for further information on the behavior of D.
armigerum.) Recently, Yanoviak et al. (2005) found that individuals of D. armigerum show controlled aerial
descent behavior. The genus has been considered primitive with respect to other members of the Dacetini
(Brown and Wilson 1959; Bolton 1998, 1999, 2000), but a phylogenetic analysis of the tribe is necessary to
fully understand the relationships of its constituent species and genera. Current molecular phylogenetic evi-
dence suggests that Dacetini may not be monophyletic (Brady et al. 2006).
Although workers of Daceton are conspicuous and commonly encountered and collected, there has been
no evidence of more than one species in the genus. A study of specimens collected in recent and past biodiver-
sity surveys in Peru and Brazil has revealed the existence of a second remarkable species. Herein we describe
this new species and provide a review of the genus.
Material and methods
Study sites
Specimens of the new species were collected from the canopies of two rainforests in the Amazon water-
shed, one in Peru and one in Brazil. The Peruvian samples were collected in Iquitos, Loreto. Individual work-
ers were attracted to a bait consisting of a mixture of honey and tuna placed approximately 25 m above the
ground on a branch of a Sloanea sp. (Elaeocarpaceae) tree. Collections were conducted during both day and
night. The Brazilian samples were collected by insecticide fogging of a Terra Firma canopy forest within 70
km of Manaus during the dry season (July–August 1979) by T. L. Erwin and co-workers. The canopy-fogging
technique utilized by Erwin consisted of a radio-controlled Dyna-fog machine suspended in the canopy and
rotated through a 90° angle while discharging insecticide into the surrounding vegetation (Erwin 1983).
Insects and other arthropods falling from the canopy were collected at ground level into 4 oz Nalgene bottles
containing 70% alcohol that were mounted on the bottoms of funnel-shaped sheets (Erwin 1983).
Entomological Collections
Specimens for this study have been examined from or have been deposited in the following institutions:
BMNH The Natural History Museum, London, United Kingdom.
CPDC Centro de Pesquisa do Cacau, CEPEC/CEPLAC, Ilheus, Bahia, Brazil.
IAvH Instituto de Investigación de Recursos Biológicos “Alexander von Humboldt,” Villa de
Leyva, Colombia.
ICN Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia.
MCZC Museum of Comparative Zoology, Cambridge, Massachusetts, U.S.A.
MUSM Museo de Historia Natural “Javier Prado,” Universidad Nacional Mayor de San Marcos,
Lima, Perú.
MZSP Museu de Zoologia da Universidade de São Paulo, São Paulo, Brazil.
USNM National Museum of Natural History, Smithsonian Institution, Washington DC, U.S.A.
ZMUC Zoological Museum, University of Copenhagen Universitetsparken 15, DK-2100, Denmark.
Morphology and measurements
Examination and measurement of specimens were completed at various magnifications using a light stere-
omicroscope (Leica MZ16) and were recorded to the nearest 0.001 mm. All measurements are given in milli-
meters unless noted otherwise. Specimens were photographed using a JVC KY-F70B video camera mounted
Zootaxa 1749 © 2008 Magnolia Press · 29
NEW SPECIES OF DACETON PERTY FROM SOUTH AMERICA
on a Leica Z16 APO microscope with a Leica Motor-focus System attached to an IBM Intellistation M Pro
computer, on which composite images were assembled using Auto-Montage Pro Version 5.03.0018 BETA
software® (Synoptics Ltd.). Scanning electron micrographs were taken using an Amray 1810 Scanning Elec-
tron Microscope (SEM) with LaB6 electron source. Specimens were sputter-coated with 20–30 nm gold/pal-
ladium alloy 60:40 wt% in a Cressington Scientific 108auto/SE. During the coating process, the samples were
tilted and rotated to ensure uniform coverage. Images were cropped and enhanced using Photoshop CS2 Ver-
sion 9.0.2® (Adobe Inc.). Morphological terminology employed throughout follows Bolton (1994) with mod-
ifications where noted. Anatomical abbreviations are as follows:
EL Eye Length: maximum diameter of compound eye in full-face view.
GL Gaster Length: the length of the gaster in lateral view from the anteriormost point of first gas-
tral segment (fourth abdominal segment) to the posteriormost point.
HL Head Length: the length of the head proper, excluding the mandibles; measured in full-face
view from the midpoint of the anterior clypeal margin to a line drawn across the posterior
margin of cephalic lobes.
HW Head Width: the maximum measurable width of the head in full-face view.
ML Mandible Length: in ventral view, the distance from a line drawn across the lateral condyles
where the mandibles attach the cephalic capsule to the apical tooth with the mandibles closed.
ML' Mandible length: in full-face view, the distance from the anterior margin of the clypeus to the
apical tooth with the mandibles closed.
MW Mandible Width: in full-face view, the maximum measurable width of the mandible.
PL Petiole Length: the straight line from the posteriormost margin of the petiole to the posterior-
most margin of the metapleural lobe, in lateral view.
PPL Postpetiole Length: the maximum length of the postpetiole in lateral view.
PSL Propodeal Spine Length: the distance from the tip of the propodeal spine to the nearest border
of the propodeal spiracle.
PW Pronotal Width: the maximum width of the pronotum in dorsal view, measured as the distance
between the tips of the lateral pronotal spines.
SL Scape Length: the maximum length of the antennal scape excluding the condylar bulb.
TL Total Length: HL+ML+WL+PL+PPL+GL.
WL Weber’s Length: in lateral view, the distance from the posteriormost border of the metapleural
lobe to the anteriormost border of the pronotum.
CI Cephalic Index: (HW/HL) X 100.
MI Mandibular Index: (ML/HL) X 100.
PI Petiolar Length Index: (PL/WL) X 100.
PSI Propodeal Spine Index: (SpL/WL) X 100.
SI Scape Index: (SL/HW) X 100.
Systematic treatment
Daceton Perty
Daceton Perty, 1833: 136. Type-species: Formica armigera Latreille, 1802: 244, by monotypy.
Dacetum Agassiz, 1848: 332, unjustified emendation of Daceton. [Synonymy by Brown, 1973: 179.]
A complete diagnosis of the genus is provided by Bolton (1999, 2000).
AZORSA & SOSA-CALVO
30 · Zootaxa 1749 © 2008 Magnolia Press
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) mar-
gin 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 poste-
rior 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 gas-
tral 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, Colom-
bia, 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. [Fabri-
cius].” 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. Ma rla ) [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. Esco bar) [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,
Zootaxa 1749 © 2008 Magnolia Press · 31
NEW SPECIES OF DACETON PERTY FROM SOUTH AMERICA
FIGURES 1–6. Scanning Electron Micrographs of workers of: Daceton armigerum (1, 3, 5) and Daceton boltoni (2, 4,
6). 1–2 full-face view; 3–4 dorsal view; 5–6 mandibles in ventral view.
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.
AZORSA & SOSA-CALVO
32 · Zootaxa 1749 © 2008 Magnolia Press
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. De vri es) [MCZC]. French Gui-
ana: 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. Amazo-
nas, 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 man-
ifested 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.
Daceton boltoni Azorsa and Sosa-Calvo, new species
(figs. 2, 4, 6, 8–16, 20–22)
Holotype worker. Measurements (mm): EL 0.66, GL 3.29, HL 3.21, HW 3.47, ML 2.34, PL 1.40, PPL 0.55,
PSL 1.05, PW 3.13, SL 2.01, TL 13.9, WL 3.07. Indexes: CI 108, MI 73, PI 46, PSI 34, SI 58.
Polymorphic. Head heart-shaped; wider than long. Mandibles elongate and linear with apical fork consist-
ing of two teeth of which the ventral one is the largest. Mandibles finely reticulate-punctate. Inner (mastica-
tory) margin of mandibles with long hairs, lacking any short, thick hairs. Outer margin of mandibles with
some decumbent hairs. Mandibles, in full-face view, somewhat short and stout [(MW/ML')*100= 34–44] (fig.
23). Dorsum of clypeus with suberect to subdecumbent hairs. In some intermediate and major castes, dorsum
of head with a small but conspicuous ocellus. Ocular carina absent. Ocular crest, in lateral view, with 1–3
Zootaxa 1749 © 2008 Magnolia Press · 33
NEW SPECIES OF DACETON PERTY FROM SOUTH AMERICA
FIGURES 7–13. Scanning Electron Micrographs of workers of: Daceton armigerum (7) and Daceton boltoni (8–13). 7–
8 lateral view; 9–10 mesosoma in lateral and dorsal views, respectively; 11–12 gaster in lateral and dorsal views, respec-
tively; 13 head in lateral view.
AZORSA & SOSA-CALVO
34 · Zootaxa 1749 © 2008 Magnolia Press
FIGURES 14–16. Automontage photographs of Daceton boltoni, holotype worker. 14 body, dorsal view; 15 body, lat-
eral view; 16 head, full-face view.
erect, simple hairs. Antennal scapes not surpassing the posterior margin of head. Antennal scapes slightly
thickening towards the apex, finely reticulate and shiny, and with most of their lengths covered with sparse
decumbent to subdecumbent hairs. Base of mandibles, in lateral view, finely reticulate-punctate and ventrally
rugose, rest of lateral margin of mandibles smooth and shiny. Sides of head lacking a broad gap between bases
of mandibles and margins of head capsule when mandibles fully closed (except in two minors studied, in
which case there is a narrow gap). Depressions, adjacent to and ventral to mandibular insertion, shallow
(much deeper in D. armigerum).
Pronotum with a pair of humeral tubercles that are more carina-like and a pair of lateral, single-tipped
(rather than bifurcate) spines. Propleuron, in lateral view, strongly angulate. Posterior portion of promesono-
tum with a pair of low tubercles. Promesonotum with at least two pairs of standing simple hairs. Metanotal
groove weakly impressed. Propodeal spines long and somewhat curved inwards (U-shaped) when seen in
fronto-dorsal view. Propodeal spiracles appearing, in dorsal view, as lateral prominences of propodeum; open-
ing of propodeal spiracle longer than wide (oval).
Peduncle of petiole long. Anterior-lateral margins smooth and shiny. Dorsum of petiole anteriorly with a
pair of small spines that project latero-posteriorly. Disc of petiole finely reticulate-punctate, lacking a second
pair of tubercles or spines. Postpetiole, in dorsal view, hexagonal. Disc of postpetiole finely reticulate-punc-
Zootaxa 1749 © 2008 Magnolia Press · 35
NEW SPECIES OF DACETON PERTY FROM SOUTH AMERICA
tate and with appressed hairs. Posterior margin of postpetiole, in lateral view, angulate. Dorsum of first gastral
segment mainly with subdecumbent to decumbent hairs in addition to some appressed hairs.
FIGURES 17–22. Automontage photographs contrasting the waist segments and the dorsum of the first gastral segment
of Daceton armigerum (17–19) and Daceton boltoni (20–22).
Paratype workers. Measurements (mm): EL 0.31–0.79, GL 1.69–3.82, HL 1.08–3.57, HW 1.17–4.13,
ML 0.66–2.83, PL 0.67–1.58, PPL 0.24-0.60, PSL 0.28-1.20, PW 0.95-3.60, SL 0.74-2.11, TL 5.68–15.9, WL
1.34–3.55. Indexes: CI 106–116, MI 61–79, PI 41–52, PSI 21–40, SI 51–74, (29 measured).
Holotype worker, Peru: Loreto, Iquitos, ACTS Field Station, Canopy Walkway, 03º15’00’’S
72º55'12’’W, 20–24.iii.2006 (F. Azorsa). [Deposited in MUSM.]
Paratypes, 14 workers with same data as holotype; 15 workers, Brazil: Amazonas, Hwy ZF 2, Km 19, ca
60 Km N. Manaus, 02°30’S 60°15’W, 16.viii.1979, Terra Firma (T.L. Erwin et al.). [Deposited in BMNH (1),
IAvH (1), ICN (1), MCZC (2), MZSP (2), MUSM (6), USNM (16).]
Non-paratypic material examined. 6 workers, Brazil: Amazonas, Manaus, Reserva 41 WWF, iii.1992
(F.P. Ben to n) [CPDC].
Gyne and male. Unknown.
Range. This species is known to occur in Iquitos, Peru, and Manaus, Brazil.
Etymology. It gives us great pleasure to name this ant in honor of Mr. Barry Bolton for his extensive con-
tributions to the study of ant taxonomy and, especially, to the taxonomy of the tribe Dacetini. His worldwide
revision of the tribe Dacetini is a monumental, well-documented work containing well-executed SEM micro-
graphs and a very user-friendly taxonomical key that facilitates identification of the many miniscule, curious
species of the tribe.
AZORSA & SOSA-CALVO
36 · Zootaxa 1749 © 2008 Magnolia Press
Habitat. This species seems to be an exclusively canopy-dwelling ant. The Peruvian specimens were col-
lected on a Sloanea sp. (Elaeocarpaceae) tree.
Worker variation. Among the specimens studied, some morphological variation has been documented,
including: (i) All castes with sides of head lacking a broad gap between bases of mandibles and margins of
head capsule when mandibles are fully closed, with the exception of the two minor workers studied, in which
case there is a narrow gap. (ii) Erect hairs on the ocular crest are present in all workers examined. However,
the number of hairs varies among specimens. We suspect that these hairs are fragile and can be easily lost,
which may account for the variation observed between specimens. This seems also to apply to the standing
hairs on the median promesonotum and behind the posterior tubercles of the promesonotum. (iii) Humeral
tubercles are strongly reduced, sometimes forming a carina or absent, especially in smaller workers. (iv) The
propodeal spines of all of the Peruvian specimens examined converging at the tips (U-shaped, when seen in
fronto-dorsal view), whereas in most of the specimens from Brazil the propodeal spines are diverging, more
like the state in D. armigerum. (v) Petiolar spines short, almost absent in the smaller castes. The petiolar
spines are more developed in the specimens from Brazil.
FIGURE 23. Relationship between ML' (mandible length in full-face view) and MW (mandible width) between Dace-
ton armigerum and Daceton boltoni.
Key to the species of Daceton.
Pronotal humeral spines bifurcate, the anterior tip larger than the posterior one (fig. 3). First gastral tergite
without standing hairs (sometimes with very short, appressed hairs) (figs. 3, 7, 17–19). Mesonotum and
metanotum divided by a strongly impressed metanotal groove (fig. 3). Inner (masticatory) margin of man-
dibles with a row of short thick setae (fig. 5)............................................................. Daceton armigerum.
-. Pronotal humeral spines long and simple (figs. 4, 10, 14). First gastral tergite with suberect to subdecum-
bent hairs (figs. 4, 8, 11–12, 14–15, 20–22). Mesonotum and metanotum divided by a weakly impressed
metanotal groove (figs. 4, 10, 14). Inner (masticatory) margin of mandibles lacking a row of short thick
setae (fig. 6)....................................................................................................................... Daceton boltoni.
Zootaxa 1749 © 2008 Magnolia Press · 37
NEW SPECIES OF DACETON PERTY FROM SOUTH AMERICA
Discussion
The worker caste of Daceton boltoni shares many important character states with that of its sister species D.
armigerum, including the heart-shaped head, the large eyes located on a low cuticular prominence (Bolton
2000), the number of apical mandibular teeth, and general habitus (figs. 1–8). Daceton boltoni differs from D.
armigerum by the absence of a specialized row of thick setae on the inner (masticatory) margin of the mandi-
bles; by mandibles that are slightly shorter and more stout, which could indicate differences in prey prefer-
ences between the two species (B. Bolton, pers. comm.); by a broad gap, when seen in profile, between the
bases of the fully-closed mandibles and the margins of the head capsule; by shallow depressions adjacent to
and ventral to the mandibular insertions; by long and simple lateral pronotal spines; by a weakly impressed
metanotal groove; and by subdecumbent to decumbent hairs on the tergite of abdominal segment IV.
Behaviorally, D. boltoni appears to be very similar to D. armigerum. However, drop tests conducted at the
type locality indicate that D. boltoni individuals exhibit weak and inconsistent aerial gliding behavior relative
to those of D. armigerum (S.P. Yanoviak, pers. comm.).
These characters strongly suggest that D. boltoni is a distinct species rather than a variety of D.
armigerum. These character states are consistent across all 30 specimens examined from two distant localities
in South America (Iquitos, Peru, and Manaus, Brazil) where both species co-occur. No intermediate forms
were observed to suggest that the two forms are conspecific. Rather, D. boltoni is sympatric with D.
armigerum. Although its known distribution is currently only two locations in the Amazonian forest, it is pos-
sible and indeed likely that D. boltoni shares a broadly overlapping distribution with D. armigerum.
The discovery of a new species in the heretofore monotypic genus Daceton, a widely distributed genus of
large and conspicuous ants occurring in most South American rainforests, suggests the possibility of a similar
pattern in two other ant genera currently regarded as monotypic and likewise widely distributed, Paraponera
Smith and Gigantiops Roger. Individuals of these monotypic genera are, like those of Daceton, large and con-
spicuous. It is well worth considering that, as with Daceton, these features may have blinded myrmecologists
to the possibility that these “monotypic” genera consist in reality of multiple cryptic species.
Acknowledgments
We thank Sean Brady, Matt Buffington, Fernando Fernández, Janet Gorrell-Sutter, Regan Nally, Carlos Peña,
Ted R. Schultz, and Steve P. Yanoviak for commenting on earlier versions on the manuscript. We are indebted
to Lars B. Vilhelmsen (ZMUC) for loaning the type specimens of Myrmecia cordata, to Stefan Cover
(MCZC) for loaning invaluable material and John S. LaPolla for kindly hand-carrying them to USNM, to
Diego Perico (IAvH) for allowing JSC to examine material deposited in IAvH, to Jacques H. Delabie (CPDC)
for allowing JSC to examine material deposited in CPDC, and to Scott Whittaker (USNM) for coating speci-
mens and assisting with the scanning electronic micrographs. We thank Terry Erwin (USNM) for information
about his collecting methods and for the specimens from Brazil. Barry Bolton, John Lattke, and John Longino
critically reviewed the manuscript. We thank S. Madigosky and the research board of the Amazon Conserva-
tory for Tropical Studies (ACTS) for allowing us to conduct research on the canopy walkway. We also thank
P. Jenson and the staff at Explorama Tours for providing transportation and logistical support. Fieldwork in
Peru was supported in part by a grant from the National Geographic Society to S.P. Yanoviak. Idea Wild sup-
ported FA with equipment to study the diversity of Peruvian ants. JSC was supported in part by an Ernst Mayr
Travel Award in Animal Systematics (Harvard University), a Jacob K. Goldhaber Travel Award (University of
Maryland), and a National Science Foundation Grant (IRCEB DEB 0110073) to Ted R. Schultz (USNM).
AZORSA & SOSA-CALVO
38 · Zootaxa 1749 © 2008 Magnolia Press
References
Agassiz, J.L.R. (1848) Nomenclatoris Zoologici Index Universalis, continens nomina systematica classium, ordinum,
familiarum, et genera animalium omnium, tam viventium quam fossilium: Soloduri, 1135 pp.
Blum, M.S. & Portocarrero, C.A. (1966) Chemical releasers of social behavior. X. An attine trail substance in the venom
of a non-trail laying myrmicine, Daceton armigerum (Latreille). Psyche, 73, 150–155.
Bolton, B. (1994) Identification guide to the ant genera of the world. Harvard University Press, Cambridge, Mass., 222
pp.
Bolton, B. (1999) Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). Journal of Natural History, 33, 1639–
1689.
Bolton, B. (2000) The ant tribe Dacetini with a revision of the Strumigenys species of the Malagasy region by Brian L.
Fisher, and a revision of the Austral epopostrumiform genera by Steven O. Shattuck. Memoirs of the American Ento-
mological Institute, 65, 1–1028.
Bolton, B., Alpert, G., Ward, P.S. & Naskrecki, P. (2007) Bolton’s Catalogue of ants of the World: 1758–2005. Harvard
University Press. (CD-ROM)
Brady, S.G., Schultz, T.R., Fisher, B.L. & Ward, P.S. (2006). Evaluating alternative hypotheses for the early evolution
and diversification of ants. Proceedings of the National Academy of Sciences of the United States of America, 103,
18172–18177.
Brown, W.L., Jr. (1973) A comparison of the Hylean and Congo-West African rain forest ant faunas. In Meggers, B. J.,
Ayensu, E. S., and Duckworth, W. D. (eds.). Tropical forest ecosystems in Africa and South America: a comparative
review. Smithsonian Institution Press, 161–185, Washington, DC
Brown, W.L., Jr. & Wilson, E.O. (1959) The evolution of the dacetine ants. Quarterly Review of Biology, 34, 278–294.
Crawley, W.C. (1916). Ants from British Guiana. Annals and Magazine of Natural History, 17, 366–378.
Erwin, T.L. (1983) Beetles and other insects of tropical forest canopies at Manaus, Brazil, sampled by insecticidal fog-
ging. In: S.L. Sutton, T.C. Whitmore, and A.C. Chadwick (eds.). Tropical Rain Forest: Ecology and Management.
Special Publication Number 2 of the British Ecological Society. Blackwell Scentific Publications, Oxford. U.K., 59–
75.
Fabricius, J.C. (1804) Systema Piezatorum. Carolum Reichard, 439 pp., Brunsvigae. Fernández, F. & Sendoya, S. (2004).
List of Neotropical ants (Hymenoptera: Formicidae). Biota Colombiana, 5, 3–93.
Gronenberg, W. (1996) The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp. The Jour-
nal of Experimental Biology, 199, 2021–2033.
Guérin-Méneville, F.E. (1844) Iconographie du Règne Animal de G. Cuvier, Vol. 7, Insects. Bailliere Brothers, Paris, 576
pp.
Hölldobler, B., Palmer, J. & Moffett, M.W. (1990) Chemical communication in the dacetine ant Daceton armigerum.
Journal of Chemical Ecology, 16, 1207–1220.
Hölldobler, B. & Wilson, E.O. (1990) The Ants. Belknap Press, Cambridge, Massachusetts, 732 pp.
Kempf, W.W. (1972) Catálogo abreviado das formigas da região Neotropical (Hymenoptera: Formicidae). Studia Ento-
mologica, 15, 3–344.
Latreille, P.A. (1802) Histoire naturelle des fourmis, et recueil de memoires et d'observations sur les abeilles, les
araignees, les faucheurs, et autres insectes. Paris. 445 pp.
Moffett, M.W. & Tobin, J.E. (1991) Physical castes in ant workers: a problem for Daceton armigerum and other ants.
Psyche, 98, 283–292.
Oster, G.F. & Wilson, E.O. (1978) Caste and ecology in the social insects (Monograph in Population Biology, No. 12).
Princeton University Press, Princeton, NJ. 352 pp.
Perty, J.A.M. (1833) Delectus animalium articulatorum, quae in itinere per Brasiliam annis MDCCCXVII-MDCCCXX
jussu et auspiciis Maxilimiliani Josephi I. Bavariae regis augustissimi peracto collegerunt Dr. J. B. de Spix et Dr. C.
F. Ph. de Martius. Fascicle, 3, 125–224. Monachii.
Roger, J. (1862) Synonymische Bemerkungen. Berliner Entomologische Zeitschrift, 6, 283–297.
Smith, F. (1853) Monograph of the genus Cryptocerus, belonging to the group Cryptoceridae - family Myrmicidae - divi-
sion Hymenoptera Heterogyna. Transactions of the Entomological Society of London, (2) 2 (1854), 213–228.
Wheeler, G.C. & Wheeler, J. (1954) The ant larvae of the myrmicine tribes Basicerotini and Dacetini. Psyche, 61, 111–
145.
Wilson, E.O. (1962) Behavior of Daceton armigerum (Latreille), with a classification of self-grooming movements in
ants. Bulletin of the Museum of Comparative Zoology, Harvard, 127, 401–422.
Yanoviak, S.P., Dudley, R. & Kaspari, M. (2005) Directed aerial descent in canopy ants. Nature, 433, 624–626.
