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A Review of the Dacetine Ants of Guyana (Formicidae: Myrmicinae)
J
EFFREY
S
OSA
-C
ALVO
,T
ED
R. S
CHULTZ
,
AND
J
OHN
S. L
A
P
OLLA
(JS-C) Maryland Center for Systematic Entomology, Department of Entomology, University of
Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742, U.S.A.
(JS-C, TRS) Department of Entomology, National Museum of Natural History, Smithsonian
Institution, POB 37012, NHB, CE516, MRC 188, Washington, D. C. 20013-7012, U.S.A.
(JSL) Department of Biological Sciences, Towson University, 8000 York Road, Towson,
Maryland 21252, U.S.A.
A Review of the Dacetine Ants of Guyana (Formicidae: Myrmicinae)
J
EFFREY
S
OSA
-C
ALVO
,T
ED
R. S
CHULTZ
,
AND
J
OHN
S. L
A
P
OLLA
(JS-C) Maryland Center for Systematic Entomology, Department of Entomology, University of
Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742, U.S.A.
(JS-C, TRS) Department of Entomology, National Museum of Natural History, Smithsonian
Institution, POB 37012, NHB, CE516, MRC 188, Washington, D. C. 20013-7012, U.S.A.
(JSL) Department of Biological Sciences, Towson University, 8000 York Road, Towson,
Maryland 21252, U.S.A.
___________________________ _______________________________________________________________________________________________________________________________
Abstract.—The dacetine ants of Guyana are reviewed. One genus, Acanthognathus, is added to the
three genera reported previously from Guyana. A total of 42 species are reported, 32 of which are
new records for Guyana. Among these 32 species, the following five are new species: Pyramica
dahlanae sp. n.,Pyramica mariae sp. n.,Strumigenys acarai sp. n.,Strumigenys royi sp. n., and
Strumigenys waiwai sp. n.Pyramica dahlanae is unusual for the genus because it lacks propodeal
spines and possesses distinctive mandibular morphology. Pyramica mariae belongs to the gundlachi
group and is apparently closely related to P. denticulata based on the length of the mandibles, the
absence of spongiform tissue on the ventral margin of waist segments, general body pilosity, and
general habitus. Pyramica denticulata is illustrated in order to show morphological differences from
P. mariae.Strumigenys royi is a remarkable ant because its waist segments lack ventral spongiform
tissue, it possesses short propodeal spines, its mandibles are long and with a minute denticle
proximal to the apicodorsal tooth of the mandibular fork, and its coloration is distinctive.
Strumigenys acarai is unusual because it possesses a minute denticle on the inner margin of the
mandibles, distinctive rugulose sculpture on the dorsum of mesonotum that differs from sculpture
found on other parts of the body, and a longitudinal median carina on the promesonotum.
Strumigenys waiwai is easily recognized by the unusual multifurcate pilosity of the cephalic dorsum
and small body size. Modifications of Bolton’s (2000) keys to Pyramica and Strumigenys are provided
to accommodate the newly described species.
___________________________ _______________________________________________________________________________________________________________________________
Resumen.—En este artı
´culo se revisaron las hormigas dacetinas presentes en Guyana. El ge
´nero
Acanthognathus se adiciona a los tres ge
´neros de hormigas dacetinas conocidos anteriormente para
Guyana. Se reportan un total de 42 especies, de las cuales 32 constituyen nuevos registros en este
paı
´s. Dentro de estos 32 nuevos registros, cinco especies son nuevas: Pyramica dahlanae sp. n.,
Pyramica mariae sp. n.,Strumigenys acarai sp. n.,Strumigenys royi sp. n.,yStrumigenys waiwai
sp. n.Pyramica dahlanae es fa
´cilmente reconocida por que carece de espinas en el propodeo y su
morfologı
´a mandibular es distintiva. Pyramica mariae pertenece al grupo gundlachi yesta
´
probablemente relacionada con P. denticulata por la longitud de las mandı
´bulas, la ausencia de
tejido en forma de esponja en la margen ventral del pecı
´olo y postpecı
´olo, la pilosidad en el cuerpo
y por la forma del cuerpo en general. Tambien se ilustra Pyramica denticulata con el fin de mostrar
las diferencias morfolo
´gicas que la separan de P. mariae.Strumigenys royi es una hormiga notable
caracterizada por la carencia de tejido en forma de esponja en la parte ventral del pecı
´olo y
postpecı
´olo, por la presencia de espinas propodeales cortas, por la presencia de mandı
´bulas largas
y con un diminuto dentı
´culo pro
´ximo al diente apicodorsal en la bifurcacio
´n apical, y por la
coloracio
´n caracterı
´stica. Strumigenys acarai es una hormiga poco usual porque posee un diminuto
dentı
´culo en el borde interno pro
´ximo a la parte media de las mandı
´bulas, presenta una
caracterı
´stica escultura rugulosa en el dorso del mesonoto la cual difiere de cualquier escultura
presente en el resto del cuerpo, y presenta una carina media longitudinal en el promesonotum.
Strumigenys waiwai es fa
´cilmente reconocida por la pilosidad multi-furcada poco usual en el dorso
J. HYM. RES.
Vol. 19(1), 2010, pp. 12–43
cefa
´lico y por el reducido taman
˜o de las obreras. Modificaciones a las claves de Bolton (2000) para
identificar las species de Pyramica ydeStrumigenys son presentadas para incluir las nuevas
especies.
Key words.—Dacetini, Hymenoptera, leaf-litter sampling, Neotropics, new species, Pyramica,
Strumigenys, taxonomy
_____________________________________________________________________________ _______________________________ ______________________________________________
Species of ants in the tribe Dacetini
(Formicidae: Myrmicinae) vary greatly in
size, morphology, and behavior (Ho
¨lldob-
ler and Wilson 1990). They inhabit rotten
wood, leaf litter, soil, and trees (Ho
¨lldobler
and Wilson 1990; Bolton 1998) and feed on
a diverse variety of small arthropods
(Wilson 1953; Dejean 1985a; Bolton 1998).
It has been hypothesized that the bizarre
mandibular morphology of dacetines, in-
cluding the different mandibular modes of
action, and the conspicuous spongiform
tissue located mostly on the waist seg-
ments are adaptations for attracting and
capturing springtails (Collembola) on
which most members of the tribe presum-
ably feed (Brown and Wilson 1959; Dejean
1985a, b, 1987; Dietz and Branda
˜o 1993;
Gronenberg 1996; Kantarovich et al. 2006;
Masuko 1984, 2009).
Guyana occupies a central position
within the Guiana Shield, a large
(,1,000,000 km
2
), ancient (Proterozoic,
,2.5 billion years ago) geological area that
was once attached to West Africa (Gibbs
and Baron 1993) and that currently extends
between the Amazon and the Orinoco River
Basins. Unlike most tropical countries,
,70% of Guyana’s land, including large
tracts of primary rainforest, remains intact
or is only marginally affected by human
disturbance (Funk and Richardson 2002).
Due to the creation of new roads, the influx
of new inhabitants (especially from Brazil),
and increased mining and timber-harvest-
ing activity, this situation is rapidly chang-
ing. It is therefore imperative to gather the
biological information necessary for identi-
fying areas of conservation concern.
The ant fauna of Guyana remains largely
unknown. Wheeler (1916, 1918) and La-
Polla et al. (2007) have produced the only
publications specifically addressing this
fauna. Weber (1946) studied the fungus-
growing ants (Attini) from Guyana; Kempf
(1972) and Fernandez and Sendoya (2004),
based primarily on literature reports, re-
corded ,350 described ant species from
Guyana. LaPolla et al.’s (2007) study
recorded 230 ant species (44 genera)
collected from eight localities using leaf-
litter mini-Winkler sampling. These figures
clearly underestimate the actual number of
species present in the country; for example,
La Selva, a ,1500 ha Biological Reserve in
Costa Rica, possesses at least 437 ant
species (Longino et al. 2002). Bolton
(2000) and Fernandez and Sendoya (2004)
reported three dacetine genera and 10
species for Guyana. As a result of recent
leaf-litter surveys in Guyana (Appendix 1),
we increase the number of Guyana’s
dacetine ant species to 42, describe two
new species in the genus Pyramica Roger
and three new species in the genus
Strumigenys F. Smith, and report for the
first time species of Acanthognathus Mayr in
Guyana (Appendix 2). Although Bolton’s
generic level classification of dacetines has
recently been questioned (Baroni-Urbani
and de Andrade 2007), we choose to follow
it here for the sake of taxonomic stability in
the face of indecisive phylogenetic data.
Despite Bolton’s (2000) recent mono-
graph of the dacetines, it is clear that many
species remain to be discovered and
described in this species-rich tribe. Fortu-
nately, Bolton’s study provides the context
for rapidly identifying and describing new
species as they are discovered (Deyrup
2006; Sosa-Calvo et al. 2006; Longino 2006;
Azorsa & Sosa-Calvo 2008, Bolton et al.
V
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2008). This study summarizes the current
state of dacetine taxonomy in Guyana and
describes several new species. While
Guyana certainly contains many more
dacetine species, both described and un-
described, we believe it is important to
begin the process of documenting Guya-
nese dacetine diversity because (i) this
information will facilitate the sorting and
identification of material generated by
ongoing ant surveys in Guyana, as well
as in French Guiana, Suriname, and eastern
Venezuela (Appendix 3); (ii) this informa-
tion, combined with the information gen-
erated by those ongoing studies, will
provide data urgently required by conser-
vation efforts underway in Guyana and
Suriname (LaPolla et al. 2007; Sosa-Calvo
2007; Alonso and Mol 2007; Alonso et al.
2008); and (iii) this information can be
incorporated into ongoing studies aimed at
understanding biodiversity patterns of the
Guiana Shield, especially those generated
by the Smithsonian’s Biodiversity of the
Guianas Program (Funk et al. 2002; Funk
and Richardson 2002). This study increases
our knowledge of the species that occur in
Guyana and complements publications on
other genera including Acropyga Roger
(LaPolla 2004), Lachnomyrmex Wheeler (Fei-
tosa and Branda
˜o 2008), Pheidole Westwood
(LaPolla and Cover 2005), and Rogeria
Emery (LaPolla and Sosa-Calvo 2006).
MATERIAL AND METHODS
Specimens were examined and measured
to the nearest 0.001 mm at various magni-
fications using a Leica MZ125 light stereo-
microscope. All measurements are in milli-
meters unless noted otherwise. Specimens
were photographed using a JVC KY-F70B
video camera mounted on a Leica M420
stereomicroscope attached to an IBM In-
tellistation M Pro computer on which
composite images were assembled using
Auto- Montage Pro Version 5.03.0018 BETA
softwareH(Synoptics Ltd.). Images were
cropped and enhanced using Photoshop
CS2 Version 9H(Adobe Inc.). Scanning
electron micrographs (SEM) of uncoated
specimens (P. dahlanae,P. mariae, and S. royi)
were taken using a Philips XL-30 ESEM
with Lanthanum Hexaboride (LaB6) source
and a backscatter detector. Strumigenys
acarai and S. waiwai were sputter-coated
with 60:40 wt% Gold:Palladium alloy on a
Cressington Scientific 108 auto/SE sputter
coater to a thickness of 25-20 nm. Scanning
electron micrographs for these specimens
were taken using an Amray 1810 SEM with
LaB6 source. Terminology for morphologi-
cal features and surface sculpture, as well as
abbreviations, follow Bolton (1994, 2000)
and Harris (1979) with modifications where
noted. Anatomical abbreviations are as
follows:
EL Eye Length: Maximum dia-
meter of compound eye in
lateral view.
GL Gaster Length: Length of gaster
in lateral view from anterior-
most point of first gastral seg-
ment (third abdominal seg-
ment) to posterior-most point,
excluding sting apparatus if
protruding.
HL Head Length: Length of head
in full-face (dorsal) view, in-
cluding occipital lobes and
anterior clypeal margin but
excluding mandibles.
HW Head Width: Maximum mea-
surable width of head in full-
face view, excluding eyes.
ML Mandible Length: Exposed
length of closed mandibles, in
full-face view, from anterior
clypeal margin to apex of
mandibles.
PL Petiole Length: Straight line
from posterior-most margin of
petiole to posterior-most mar-
gin of metapleural lobe in
lateral view.
PPL Postpetiole Length: Maximum
length of postpetiole in lateral
view.
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PW Pronotal Width: Maximum
measurable width of pronotum
in dorsal view.
SL Scape Length: Maximum
length of antennal scape, ex-
cluding condylar bulb.
TL Total Length: HL +ML +WL +
PL +PPL +GL.
WL Weber’s Length: Maximum
length of diagonal connecting,
in lateral view, antero-dorsal
angle of pronotum to posterior-
most basal angle of meta-
pleuron. (5Alitrunk Length in
Bolton [2000].)
CI Cephalic Index: (HW/HL) 3
100.
MI Mandibular Index: (ML/HL) 3
100.
PI Petiolar Length Index: (PL/
WL) 3100.
SI Scape Index: (SL/HW) 3100.
Specimens examined were borrowed
from and/or have been deposited in the
following institutions: The Natural History
Museum, London, U.K. (BMNH); Centre
for the Study of Biological Diversity, Uni-
versity of Guyana, Georgetown, Guyana
(UGBC); Museum of Comparative Zool-
ogy, Harvard University, Cambridge, MA.,
U.S.A. (MCZC); Museu de Zoologia da
Universidade de Sa
˜o Paulo, Sa
˜o Paulo,
Brazil (MZSP); National Museum of Nat-
ural History, Smithsonian Institution, Wash-
ington, D.C., U.S.A. (USNM).
RESULTS AND DISCUSSION
Pyramica dahlanae Sosa-Calvo, Schultz,
and LaPolla, n. sp.
(Figs 1–5)
Material examined.—Holotype: worker, labeled:
‘‘GUYANA: Mabura Hill camp at end of Rd.
from Georgetown to Lethem Rd.; 64 m; 58u
41.9829W5u9.3139N; 29 x 2002; J.S. LaPolla et
al.; primary forest; litter sample. (JSL021029-
LS04)’’ USNM ENT No. 00442119 (UGBC).
Paratype: worker, labeled: ‘‘GUYANA: Calm
Water Creek along Essequibo River nr. Bartica;
58u37.169W6u28.069N; 23 ix 2002; J.S. LaPolla;
primary forest; litter sample. (JSL020923-LS02)’’
USNM ENT No. 00441577 (USNM).
Diagnosis (worker).—Very small (TL 5
1.38–1.42); eyes absent; mandibles linear,
elongate, and in closed position with gap
between basal mandibular teeth and ante-
rior portion of clypeus; propodeum un-
armed; ventral portion of petiole lacking
spongiform tissue.
Description (worker).—Head: in full-face
view, clypeus slightly concave anteriorly,
with long apical spoon-shaped hairs ex-
tending over mandibular gap; mandibles
sublinear and elongate; at full closure
mandibles contacting only in apical halves
of their lengths, leaving gap between them
basally; mandibles with 10 teeth, basal
tooth acute, all other teeth rounded and
flattened; teeth 1, 3, 5, 7, 9, and 10 (from
base to apex) larger than other teeth; lateral
dorsum of mandible with appressed sim-
ple hairs; eyes absent; sculpture on clypeal
plate imbricate; sculpture on cephalic
dorsum areolate and covered with squa-
mate hairs; hairs on anterior margin (lead-
ing edge) of scape spoon-shaped and
directed basad; antennal scape narrowed
basally, anterior margin abruptly ex-
panded, distinctly widest at point of
expansion; apicoscrobal hair absent. Meso-
soma: dorsum of anterior portion of prono-
tum glabrous; pronotal humeral hair ab-
sent; dorsum of promesonotum and dor-
sum and declivity of propodeum entirely
areolate; propodeum lacking spines or
denticles at its posterior margin; meso-
pleuron and metapleuron smooth and
shining; dorsal portion of mesosoma cov-
ered with appressed spoon-shaped hairs
(as on head) without erect hairs of any
kind, lateral portions glabrous. Metasoma:
petiole lacking ventral spongiform lobe,
petiolar disc areolate and covered with
slightly appressed spatulate hairs; lateral
surface of petiolar peduncle smooth and
shining; ventral surface of side of petiole
weakly sculptured; disc of postpetiole
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weakly sculptured and shining, covered
with hairs similar to those on petiole but
narrower; ventral surface of postpetiole
with well-developed spongiform lobe that
extends throughout its entire length; lateral
spongiform tissue overhanging ventral
spongiform lobe; dorsal surface of first
gastral segment smooth with some lon-
gitudinal basigastral costulae. Color: indi-
viduals light yellow to dark yellow. Hairs
throughout body lighter than integument.
Measurements: holotype (and paratype):
GL 50.3 (0.32), HL 50.34, HW 50.27 (0.28),
ML 50.09, PL 50.17, PPL 50.12 (0.11), PW
50.19 (0.18), SL 50.16, TL 51.42 (1.38), WL
50.39 (0.36). Indexes: CI 582 (79), MI 526,
PI 547 (44), SI 559 (57). (n 52)
Gyne and male.—Unknown.
Etymology.—Named after Ms. Nor Far-
idah Dahlan in recognition of her expertise
and hard work in support of Smithsonian
ant research and in gratitude for her
consistent good will and friendship. JS-C
is deeply grateful to Faridah for all her help
and care when he first arrived in the
United States.
Comments.—Pyramica dahlanae n. sp. is
most similar to members of the Nearctic
pergandei-group, which includes P. angulata
(M.R. Smith), known from the southeastern
United States and Illinois, and P. pergandei
(Emery), widely distributed in Canada and
the United States. Pyramica dahlanae shares
with those species the following characters:
(i) mandibles short (MI 25–35) and, in
frontal view, narrow and elongate, dentate
only at the apical portion where they are in
contact leaving an edentate gap between
them; (ii) specialized mandibular dentition
(alternating pattern of longer and shorter
mandibular teeth); (iii) lateral clypeal mar-
gins, in dorsal view, extending beyond the
line of the outer margin of the mandibles
when closed; and (iv) preocular carina
broad and conspicuous. Pyramica dahlanae
differs from the species in the pergandei-
group in four character states: (i) 10
mandibular teeth (15–16 in the pergandei-
group), (ii) absence of triangular teeth on
the propodeum (present in the pergandei-
group), (iii) absence of a well-developed
spongiform tissue on the ventral portion of
the petiole (present in the pergandei-group),
and (iv) shorter antennal scape, SI 57–59 (SI
65–84 in the pergandei-group).
The mandibles of P. dahlanae are similar
to those within the pergandei-group in that
they contact in the apical third, producing
a basal gap between the mandibles. This
condition is different from the one found in
species in the ohioensis-group, in which the
masticatory margins contact through al-
most their entire lengths and in which the
mandibles are triangular rather than elon-
gate. Elongate mandibles can be found in
the gundlachi- and argiola-groups, the latter
an Old World group introduced into the
United States (P. hexamera (Brown)). Man-
dibles in P. hexamera are highly distinctive
with an elongate and spiniform apicodor-
sal tooth and two long preapical teeth (see
Bolton 2000 for further information). Spe-
cies of the gundlachi-group share with P.
dahlanae the absence of a spongiform lobe
on the ventral surface of the petiole but
differ from P. dahlanae in: (i) mandibular
length and morphology, (ii) the presence of
a pair of triangular teeth or short spines on
the propodeum, and (iii) the presence of
pronotal humeral hairs and, in almost all
species, a pair of laterally projecting apico-
scrobal hairs.
Pyramica dahlanae may also be related to
P. paradoxa Bolton, known from a single
worker collected in Costa Rica. Both
species share the absence of propodeal
spines; however, P. dahlanae differs from P.
paradoxa by the shape of the mandibles,
and the head and mesosoma strongly
areolate with the meso- and metapleuron
smooth and shining. The head and meso-
soma are mostly smooth and shining in P.
paradoxa. Although P. dahlanae shares a
number of character states with some
members of the aforementioned groups,
this species is not easily placed in any of
the species groups defined by Bolton
(2000).
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Figs 1–5. Scanning electron micrographs of the holotype worker of Pyramica dahlanae, new species. 1, Full-face
(dorsal) view. 2, Closed mandibles. 3, Dorsal view of petiole and postpetiole. 4, Dorsal view of mesosoma. 5,
Lateral view.
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MODIFIED VERSION OF KEY IN BOLTON (2000)
Pyramica dahlanae will not key out to any known species of Pyramica in either the Nearctic or the
Neotropical keys of Bolton (2000). The key to Neotropical species can be modified as below to include
P. dahlanae. The numbering of couplets follows Bolton (2000).
7. Dorsum of postpetiole (5disc) smooth and with weak costulae ............... 7b
– Dorsum of postpetiole entirely reticulate-punctate . . . ..... couplet 12 in Bolton (2000)
7b. Cephalic dorsum with 1 or 2 pairs of standing hairs. Apicoscrobal and pronotal
humeral hairs present… . . . ...................... couplet 8 in Bolton (2000)
– Cephalic dorsum lacking standing hairs. Apicoscrobal and pronotal humeral hairs
absent ........................................ P. dahlanae new species
Pyramica mariae Sosa-Calvo, Schultz, and
LaPolla, n. sp.
(Figs 6, 8, and 10)
Material examined.—Holotype: worker, labeled
‘‘GUYANA: Mt. Ayanganna montane forest;
1300 m; 59u57.9699W5u22.4839N; 13.x.2002;
T.R. Schultz,J. LaPolla,C. Marshall,R. Williams;
litter sample.’’ USNM ENT No. 00413858.
(UGBC). Paratypes: 3 workers, same locality as
in holotype. USNM ENT No. 00413859,
00442882, 00442883. (USNM).
Diagnosis (worker).—Mandibles linear,
elongate, and narrow; inner margin of
mandibles with two clearly defined teeth,
which are larger than the rest; labral lobes
short with long trigger hairs at their apices;
metapleuron smooth and shining; ventral
portions of petiole and postpetiole lacking
spongiform tissue.
Description (worker).—Possessing char-
acters of the gundlachi-group and gundlachi-
complex (Bolton 2000). Head: in full-face
view nearly as broad as long; inner margin
of elongate mandibles slightly concave to
more or less straight, with 4 teeth on left
mandible and 3 on right mandible, of
which a pair of teeth are larger on each
mandible (same in paratypes); with 2 mi-
nute intercalary denticles between apico-
dorsal and apicoventral fork teeth; labral
lobes short, almost invisible in full-face
view; trigger hairs long; eyes with 3
ommatidia in longest row, with 6–7 om-
matidia in total. Cephalic dorsum with two
pairs of erect hairs: one pair located close
to occipital margin and another pair
located close to highest point of vertex;
each upper scrobal margin with a short
apicoscrobal hair that projects laterally.
Mesosoma: pronotum with a pair of short
humeral hairs that project laterally; meso-
notum with a pair of short, erect, stiff hairs;
mesopleuron and metapleuron mostly
smooth and shining; dorsum of promeso-
notum, propodeum, and propodeal decliv-
ity strongly reticulate. Metasoma: peduncle
of petiole long, length of petiole 3–3.5 times
longer than its disc; petiolar disc reticulate-
punctate, with a pair of erect hairs on
posterior portion of disc; ventral portion of
petiole lacking spongiform tissue; disc of
postpetiole reticulate, ventral portion of
postpetiole lacking spongiform tissue; pos-
terior portion of postpetiole disc with a
row of 4 erect hairs; first gastral tergite
almost entirely reticulate except for a small
portion at posterior portion of tergite.
Individuals light brown to brown.
Measurements: holotype (and paratype):
GL 50.59 (0.48), HL 50.52 (0.48–0.50),
HW 50.42 (0.38–0.46), ML 50.36 (0.36–
0.38), PL 50.28 (0.24–0.27), PPL 50.12,
PW 50.27 (0.23–0.24), SL 50.30 (0.30–
0.31), TL 52.47 (2.24–2.28), WL 50.58
(0.55–0.56). Indexes: CI 581 (78–92), MI 5
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73 (72–75), PI 548 (43–49), SI 571 (65–82).
(n 54)
Gyne and male.—Unknown
Etymology.—Named in honor of the first
author’s mother, Maria del Carmen Calvo,
in gratitude for her encouragement and
support.
Comments.—Pyramica mariae n. sp. is
clearly a member of the gundlachi-group
(refer to Bolton [2000: 176–179 p.] for
further information). Within the gundlachi-
group, Bolton (2000) identified two com-
plexes, crassicornis and gundlachi.Pyramica
mariae belongs to the gundlachi complex
and resembles P. denticulata (Mayr), P.
enopla Bolton, and P. vartana Bolton. Pyr-
amica mariae shares with P. vartana the
smooth and shining mesopleuron and
Figs 6–11. Full-face (dorsal) and lateral views of the holotype worker of Pyramica mariae, new species (6, 8, 10)
and P. denticulata (7, 9, 11).
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metapleuron, but P. mariae can be distin-
guished from P. vartana by the form of the
apicoscrobal and pronotal humeral hairs,
both short and stiff (mariae) rather than
long and filiform (vartana), and the disc of
the postpetiole is reticulate (mariae) rather
than smooth and shining (vartana).
Pyramica mariae is of similar size and
color as P. enopla. However, P. mariae
differs from P. enopla in that the apicoscro-
bal, humeral, and mesonotal hairs are
short, erect, and stiff (mariae) rather than
long and filiform (enopla); the metapleuron
is smooth and shining (mariae) rather than
reticulate (enopla); the dorsum of the
petiole bears a single pair of hairs (mariae)
rather than two pairs of hairs (enopla); and
the dorsum of the postpetiole lacks an
anterior pair of hairs (mariae), present in
enopla.
Pyramica mariae can easily be confused
with P. denticulata (Figs 7, 9, and 11) with
which it shares the most character states.
However, the species can be separated by:
(i) mandibular dentition: P. denticulata has
5–10 preapical denticles of similar size,
whereas P. mariae has 3–4 preapical denti-
cles, two of which are larger than the rest.
In Pyramica mariae, at least in the four
specimens examined, there are 4 teeth on
the left mandible and 3 teeth on the right
mandible; (ii) mesosomal sculpture: the
metapleuron in P. denticulata is reticulate,
whereas in P. mariae it is smooth and
shining; (iii) petiole proportions: the petio-
lar peduncle in P. denticulata is relatively
shorter (PI 38–42) than in P. mariae (PI 43–
49) (Figs 12–13).
The four specimens known of P. mariae
were collected in a leaf-litter sample
extracted with a mini-Winkler. The sample
was collected in a primary lower montane
forest (1300 m). Other species in the
gundlachi-group have been recorded from
wet forest habitats and from lowland rain-
forest to cloud forest and some in agro-
ecosystems. Pyramica denticulata, the spe-
cies perhaps most closely related to P.
mariae, has been collected in lowland (,
1000 m) forests in Panama (Sosa-Calvo et
al. 2006) to subtropical forests in the wet
Chaco region of Argentina (Theunis et al.
2005). Nothing is known about the biology
of P. mariae other than the collection data.
MODIFIED VERSION OF KEY IN BOLTON (2000)
In Bolton’s (2000) key, Pyramica mariae keys out to P. denticulata. The key can be modified as
below to include P. mariae. Numbering of couplets follows Bolton (2000).
23. In lateral view, postpetiole lacking ventral spongiform lobe; sometimes a minute
vestige visible; mesonotum with a pair of erect hairs . . .................. 23b
– In lateral view, postpetiole with reduced ventral spongiform lobe but distinct; if lobe
very shallow then mesonotum with pair of straggly (i.e., laid out in an irregular,
untidy way) flagellate hairs . ...................... couplet 25 in Bolton (2000)
23b. Mandibles long, MI 72–85. Dorsum of pronotum lacking pair of stiff erect hairs . . . 23c
– Mandibles short, MI 58–65. Dorsum of pronotum with pair of stiff erect hairs ... eggersi
23c. Inner margin of mandibles with 5–10 preapical denticles of similar size. Metapleuron
densely reticulate. Peduncle of petiole short, PI 38–42 . . ............ denticulata
– Inner margin of mandibles with 3–4 preapical denticles, two distinctly larger than rest.
Metapleuron smooth and shining. Peduncle of petiole elongate, PI 48–49 . . ...
................................................. mariae new species
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Strumigenys royi Sosa-Calvo, Schultz, and
LaPolla, n. sp.
(Figs 14–25)
Material examined.—Holotype: worker, labeled
‘‘GUYANA: Kanuku Mts.: Nappi Creek. camp;
128 m; 59u33.9639W, 3u21.0189N; 24.x.2002; J.S.
LaPolla; forest; on tree trunk. (JSL021024-08)’’
USNM ENT No. 00537288. (UGBC). Paratype:1
worker, same locality as in holotype. USNM
ENT No. 00537289. (USNM).
Diagnosis (worker).—Leading edge of
antennal scape with all hairs curving to
apex, lacking hairs that curve to the base of
segment; mandibles long and linear with a
small, but conspicuous preapical tooth
Fig. 12. Relationship between head width and head length among Pyramica denticulata,P. mariae, and P. enopla.
Measurements in millimeters.
Fig. 13. Relationship between petiole length and Weber’s length among Pyramica denticulata,P. mariae, and P.
enopla. Measurements in millimeters.
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close to the apicodorsal teeth; propodeum
with small denticles; segments of the waist
with ventral margin lacking spongiform
tissue of any kind; first gastral sternite
lacking spongiform pad; body strongly
reticulate and with area within each re-
ticulation verrucose; coloration distinctive:
mandibles mostly whitish, antennae and
legs yellowish, mesosoma mostly ferrugi-
nous, waist segments light brown, and
head and gaster mostly dark brown or
black.
Description (worker).—Head: in full-face
view, mandibles thick throughout most of
their length and abruptly narrowing just
before apex by sudden oblique divergence
of inner margin, a minute but conspicuous
preapical denticle arising on this oblique
Figs 14–22. Scanning electron micrographs of the holotype worker of Strumigenys royi, new species. 14, Lateral
view. 15, Lateral view of head. 16, Full-face view. 17, Closed mandibles. 18, Lateral view of mesosoma. 19,
Lateral view of petiole, postpetiole, and gaster. 20, Dorsal view of mesosoma. 21, Dorsal view of mesosoma,
waist segments, and first gastral tergite. 22, Dorsal view of waist segments (petiole and postpetiole).
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section; mandibles with intercalary denti-
cle that arises from dorsal base of apico-
ventral tooth; in full-face view, anterior
margin of clypeus transverse to very
slightly concave and with at least 6
narrowly spatulate elongate hairs; dorsum
of clypeus finely reticulate-punctate and
with short, appressed, simple hairs; ocular
carina short, ending at eye level; leading
edge of scapes with all hairs curved or
inclined toward apex of scape; funicular
segments II and III long [holotype: 2
nd
5
0.073, 3
rd
50.092; paratype: 2
nd
50.079, 3
rd
50.092], their lengths, when combined,
almost as long as funicular segment IV;
occipital margin deeply emarginate, form-
ing prominent rounded cephalic lobes;
dorsum of head with two pairs of erect
fine hairs: one pair close to margin of
occipital concavity and another close to
highest point of vertex, clearly differing
from appressed simple ground-pilosity
Figs 23–25. Automontage images of a paratype of Strumigenys royi, new species. 23, Full-face view. 24, Dorsal
view. 25, Lateral view.
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(sensu Bolton 2000:998: referring to ‘‘the
short pilosity often present on cephalic
dorsum, dorsolateral margins of head,
promesonotum and its margins. These
hairs could be simple or spatulate to
orbicular, usually decumbent to appressed
and may rarely be elevated’’); eye with 13–
14 ommatidia on longest row; apicoscrobal
hair elongate and simple (this hair lacking
on holotype due to damage); dorsum of
head strongly reticulate and with areas
within each reticulation verrucose (i.e.,
containing wart-like protuberances). Meso-
soma: humeral hair elongate and simple,
similar in shape to apicoscrobal hair but
longer; pilosity on dorsum of pronotum
consisting of decumbent hairs; dorsum of
pronotum with irregular rugae and mark-
edly reticulate with areas within reticula-
tion verrucose; mesonotum, in lateral view,
raised and separated from pronotum by
transverse or rounded carina; mesonotum,
in lateral view, with pair of erect elongate
simple hairs and pair of short erect simple
hairs; dorsum of mesonotum with conspic-
uous longitudinal rugae and strongly
reticulate with area within reticulation
verrucose; mesopleuron and metapleuron
separated by deep scrobiculate constriction
that extends to dorsum of alitrunk to form
metanotal groove; in lateral view, constric-
tion extends backward from propodeum
throughout base of propodeal denticles,
before beginning of propodeal declivity;
propodeum with small denticles; declivity
of propodeum with thin reticulate carina;
mesopleuron mostly reticulate and with
area within reticulation verrucose; proximal
to border with metapleuron (and especially
upper portion of katepisternum), reticula-
tions fading leaving only verrucose sculp-
ture visible; anepisternum mostly verru-
cose; metapleuron reticulate and with areas
within reticulation verrucose. Metasoma:
waist segments lacking ventral spongiform
tissue; petiole with anterior acute process;
node of petiole, in lateral view, rounded;
pilosity on petiole, in frontodorsal view,
consisting of anterior pair of elongate,
simple suberect hairs and posterior trans-
verse row of four elongate, simple suberect
hairs (hair on each side of petiole and pair
on posterior dorsum of petiole); posterior
margin of petiolar node with low spongi-
form crest; disc of petiole, in dorsal view,
rugose-reticulate and with area within
reticulation verrucose. Postpetiole, in lateral
view, globose and in fronto-dorsal view,
with two transverse rows of four elongate,
simple suberect hairs, located on anterior
and posterior portions of postpetiole. (Dis-
tribution of these hairs similar to that of
posterior row on petiole.) Anterior margin
of postpetiole, in dorsal view, concave;
postpetiole wider than long [length 5
0.205, width 50.238]; posterior margin of
postpetiolar disc with small spongiform
crest; disc of postpetiole reticulate with
areas within reticulations verrucose. First
gastral tergite finely reticulate-substrigulate
with some verrucose sculpture confined to
basigastral area; dorsum of first gastral
tergite with widely spaced elongate erect
simple hairs. Similar hairs on gastral ster-
nite but more abundant; first gastral sternite
reticulate, differing from sculpture on ter-
gite; basigastral costulae longitudinal,
spaced, and very short but conspicuous.
Color: anterior portion of head yellowish
and gradually increasing in color to ferru-
ginous by level of eyes and dark brown on
rest of head. Mandibles mostly whitish with
tips ferruginous to dark brown. Mesosoma
ferrugineous; petiole and postpetiole light
brown; legs and antennae yellowish,
slightly lighter in color than waist segments;
first gastral tergite black or dark brown,
second and third gastral tergites ferrugi-
neous, fourth gastral tergite yellowish; first
to third gastral sternites ferrugineous,
fourth gastral sternite yellowish.
Measurements: holotype (and paratype):
EL 50.16 (0.14), GL 50.79 (0.78), HL 5
0.86, HW 50.65, ML 50.49 (0.52), PL 5
0.40 (0.37), PPL 50.19 (0.20), PW 50.36
(0.35), SL 50.57 (0.59), TL 53.53, WL 5
0.79 (0.80). Indexes: CI 575, MI 557 (60),
PI 551 (46), SI 588 (90). (n 52)
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Gyne and male.—Unknown.
Etymology.—This species is named in
honor of Roy Snelling to acknowledge his
numerous contributions to the taxonomy
of ants, bees, and wasps. He will live on
through the solid foundation he provided
for ant taxonomy and through the thou-
sands of specimens that he left behind for
myrmecologists to ponder over for many
years to come.
Biology.—Strumigenys royi was col-
lected from an upright, living tree trunk
in a small dirt tunnel (likely made by
termites) that ran up the side of the
tree.
Comments.—This large species is easily
distinguished from any other species in the
genus Strumigenys (sensu Bolton 2000) by
lacking the spongiform tissue on the
ventral margin of the waist segments
(petiole and postpetiole) and lacking a
spongiform pad on the first gastral sternite,
by having the apical fork of the mandibles
with an intercalary denticle that arises
from the dorsal base of apicoventral tooth,
by having antennal funicular segments II
and III, when combined, almost as long as
funicular segment IV (shared with S. fair-
childi Brown), by having a minute denticle
close to the apicodorsal tooth (similar in S.
lanuginosa Wheeler), and by having
marked body sculpture. Due to this com-
bination of characters it is difficult to place
this species in any of the species groups
given by Bolton (2000).
Strumigenys royi differs from S. idiogenes
Bolton, to which it keys out in Bolton’s
(2000) key, as the latter possesses: a
larger and conspicuous lobe on ventral
margin of postpetiole, a narrow spongi-
form pad on the base of first gastral
sternite, asymmetrical dentition on the
mandibles, and a pair of narrow spines
on the propodeum.
MODIFIED VERSION OF KEY IN BOLTON (2000)
Strumigenys royi will key out to S. idiogenes in Bolton’s (2000) ‘‘key to Neotropical-Nearctic
Strumigenys species.’’ The key for the species of Strumigenys can be modified as below to include S.
royi. Numbering of couplets follows Bolton (2000).
4. Mandibles without intercalary teeth or denticles that arise between apicodorsal and
apicoventral teeth of apical fork, nor arise from dorsal base of apicoventral
tooth ........................................ couplet 5 of Bolton (2000)
– Mandible with 1 or 2 intercalary teeth or denticles that arise between apicodorsal and
apicoventral teeth of apical fork, or arise from dorsal base of apicoventral
tooth ........................................ couplet 10 of Bolton (2000)
10. Mandibles without, or with only one, preapical tooth or denticle couplet 11 of Bolton
(2000)
– Mandible with 2 preapical teeth or denticles . ........... couplet 15 of Bolton (2000)
11. Preapical dentition consisting of single tooth on one or both mandibles; preapical tooth
conspicuously dentiform and located close to apicodorsal tooth ............. 12
– Preapical dentition absent from both mandibles or single minute denticle present; if
the latter denticle located close to midlength, not near apicodorsal tooth ...... 14
12. First gastral tergite very densely clothed with long fine flagellate hairs. Dorsolateral
margin of head with 2 freely laterally projecting long flagellate hairs, one at level of
eye, other apicoscrobal . . .................................... lanuginosa
– First gastral tergite with stout curved hairs that are remiform or apically spatulate or
simple erect standing hairs. Dorsolateral margin of head without projecting
flagellate hairs or with single hair, in apicoscrobal position . . . ............. 13
13. Scape strongly dorsoventrally flattened and very broad; in full-face view maximum
width of scape greater than maximum width of mandible. First gastral tergite
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unsculptured. Pronotal humeral hairs stiff and stout. With head in profile highest
point of vertex without erect hairs . . . .......................... platyscapa
– Scape subcylindrical; in full-face view maximum width of scape less than maximum
width of mandible. First gastral tergite with sculpture present other than
basigastral costulae. Pronotal humeral hairs elongate or flagellate. With head in
profile highest point of vertex with pair of erect hairs . . .................. 13b
13b. Ventral surface of postpetiole with large and distinct spongiform lobe. Propodeal
spines long. Mandibles with asymmetrical preapical dentition (left mandible
without trace of preapical dentition, right mandible with small slender preapical
tooth located close to apicodorsal tooth and slightly smaller than intercalary
tooth) .................................................... idiogenes
– Ventral surface of postpetiole without spongiform lobe or crest. Propodeal spines
short. Mandibles with symmetrical preapical dentition (both mandibles with small
preapical tooth located close to apocidorsal tooth) ............ royi new species
Strumigenys acarai Sosa-Calvo, Schultz,
and LaPolla, n. sp.
(Figs 26–39)
Material examined.—Holotype:worker,la-
beled ‘‘GUYANA: Upper Takutu-Upper Esse-
quibo, Acarai Mountains, New Romeo Camp,
1069 m., 58u57.8289W, 1u19.9389N; 14.x.2006;
T.R. Schultz,J. Sosa-Calvo,C.J. Marshall,R.
Williams;1uupland forest; leaf-litter sample.
(JSC061014-01)’’ USNM ENT No. 00537294.
(UGBC). Paratypes:9workers,labeled
‘‘GUYANA: Upper Takutu-Upper Essequibo,
Acarai Mountains, New Romeo Camp, 1069 m.,
58u57.8289W, 1u19.9389N; 14.x.2006; T.R. Schultz,
J. Sosa-Calvo,C.J. Marshall,R. Williams;1u
upland forest; leaf-litter sample. (JSC061014-02,
JSC061014-03). USNM ENT No. 00537295–
00537303. (BMNH (1), MCZC (1), and USNM
(6))
Diagnosis (worker).—Small (TL 1.62–
1.79); eyes vestigial, consisting of one or
two ommatidia; masticatory margin of
mandibles with an inconspicuous tooth,
visible under high magnifications; leading
edge of antennal scapes with some hairs
that curve toward the base of scape;
dorsum of promesonotum rugulose and
with a conspicuous median longitudinal
ruga that extends for entire length of
promesonotum; petiole lacking a ventral
process or spongiform tissue of any kind.
Description (worker).—Head: mandibles
elongate with outer margin convex; inner
margin of mandibles with minute incon-
spicuous preapical denticle in mandible’s
midlength, visible under high magnifica-
tion; apical fork of mandibles lacking
intercalary teeth; anterior margin of cly-
peus slightly concave or transverse; dor-
sum of antennal scape imbricate; anterior
edge of antennal scape with at least 3
narrowly spatulate hairs curving toward
base, some hairs on scape multi-furcate
(Fig. 30); hairs on upper margin of scrobe
narrowly spatulate and curving anteriorly;
apicoscrobal hair flagellate; dorsum of
head strongly areolate; ocular carina failing
to reach level of eyes; eyes minute, with
only 1 (one paratype, most of them with
two) or 2 ommatidia; dorsum of head with
fine subdecumbent hairs, some of which
curve medially and with pair of erect hairs
present on cephalic margin (very difficult
to see). Mesosoma: humeral hair flagellate;
anterior portion of pronotum, in dorsal
view, strongly reticulate; dorsum of pro-
mesonotum rugulose and with conspicu-
ous median longitudinal ruga or carina
that extends for entire length of promeso-
notum; areas between rugae smooth and
shining; dorsum of promesonotum with
subdecumbent hairs that curve medially,
most hairs directed backwards; posterior
half of promesonotum areolate; mesono-
tum with pair of flagellate simple hairs;
dorsum of propodeum and declivity of
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propodeum areolate; mesopleuron and
metapleuron mostly smooth and shining;
mesopleuron and metapleuron divided by
strip of aerolate sculpture that originates at
ventral margin of mesopleuron and meta-
pleuron and extends dorsally in direction
of metanotal groove, this strip incomplete,
fading before it connects with metanotal
groove; propodeal spines long; declivity of
propodeum with a thin carina. Metasoma:
dorsum and sides of petiole strongly
areolate; ventral margin lacking spongi-
form tissue or process of any kind; node of
petiole, in lateral view, with two transverse
rows each consisting of four long subde-
cumbent and simple hairs and composed
of two hairs medially and two hairs
distally (Fig. 35); posterior margin of pet-
iolar node with small spongiform crest,
best seen in fronto-dorsal view; in dorsal
view, lateral projections of crest conspic-
uous and triangular; postpetiole with ven-
tral and lateral spongiform lobes well
developed; dorsum of postpetiole with
longitudinal rugae, areas between rugae
smooth and shining; base of first gastral
sternite bearing conspicuous pad of spon-
giform tissue; basigastral costulae lon-
gitudinal and sharply defined, longer than
maximum length of disc of postpetiole;
dorsum of first gastral tergite with numer-
ous long flagellate hairs; entire tergite
posterior to basigastral costulae smooth
and shining.
Measurements: holotype (and paratypes):
GL 50.40 (0.35–0.41), HL 50.42 (0.39–
0.41), HW 50.31 (0.29–0.33), ML 50.25
(0.24–0.25), PL 50.20 (0.15–0.19), PPL 5
0.09 (0.08–0.11), PW 50.18 (0.17–0.19), SL
50.29 (0.27–0.30), TL 51.77 (1.62–1.79),
WL 50.41 (0.38–0.42). Indexes: CI 573
(74–81), MI 559 (58–64), PI 548 (38–51), SI
594 (88–96). (n 510)
Gyne and male.—Unknown.
Etymology.—The name of this species
refers to the Acarai Mountains, in the
Upper Takutu-Upper Essequibo region of
southern Guyana, where specimens of this
species were collected.
Comments.—Strumigenys acarai seems to
belong to the S. silvestrii species group
(sensu Bolton 2000), sharing with some
members of that group: (i) the ventral
margin of petiole lacking spongiform tis-
sue; (ii) the small worker size (HL 0.39–
0.43, HW 0.29–0.33, TL 1.62–1.79, WL 0.38–
0.42 in S. acarai, HL 0.36–0.52, HW 0.28–
0.44, TL 1.5–2.2, WL 0.36–0.56 in the S.
silvestrii group); (iii) the apical fork of
mandibles lacking intercalary denticles;
(iv) the leading edge of the antennal scapes
having two or more hairs that are curved
or inclined toward the base of the scape; (v)
the eyes minute, usually with only 1–3
ommatidia in total; (vi) the preocular
carina short and ending before the level
of the eye; (vii) the propodeal spines
usually present; and (viii) the head and
alitrunk usually sculptured but the meso-
pleuron and metapleuron entirely smooth
and shining.
Strumigenys acarai shares with S. cari-
nithorax Borgmeier, in addition to the
character states mentioned above, the pres-
ence of a median fine longitudinal carina
on the mesonotum. Strumigenys acarai
differs from S. carinithorax, however, by
having the ground-pilosity of the head,
from above level of eye to close to occipital
margin, very narrowly spatulate (almost
simple) rather than spatulate as in S.
carinithorax; the mandibles with a pair of
minute inconspicuous preapical denticles
proximal to the midlength of the mand-
ibles rather than with a pair of spiniform
preapical teeth as found in S. carinithorax,
which are located in the distal third, and
with a minute pair of denticles that may be
difficult to see that are just proximal to the
midlength of the mandibles (Bolton 2000);
the leading edge of the antennal scapes
with some multifurcated narrowly spatu-
late hairs rather than spoon-shaped hairs
of S. carinithorax.Strumigenys acarai shares
with S. waiwai (described here) the pres-
ence of multifurcated hairs. In the former
species, however, these hairs seem to be
restricted to the leading edge of the
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antennal scapes, whereas in the latter these
hairs are present on the dorsum of the
head. The two species described here (S.
acarai and S. waiwai) also differ from each
other in mandibular dentition (inconspic-
uous pair of teeth at midlength of mand-
ibles in S. acarai, and having a pair of
spiniform teeth and a minute, but conspic-
uous pair of teeth at midlength of mand-
ibles in S. waiwai), in the sculpture of the
dorsum of the promesonotum (rugulose
and with a conspicuous median longitudi-
nal ruga in S. acarai, and strongly aerolate
in S. waiwai), and in the length of the
costulae on first gastral tergite (longer than
the maximum length of the disc of post-
petiole in S. acarai, and barely as long as the
disc of postpetiole in S. waiwai).
Figs 26–36. Scanning electron micrographs of a paratype worker of Strumigenys acarai, new species. 26, Head
and mandibles in full-face view. 27, Cephalic capsule in full-face view. 28, Mandibles in dorsal view. 29, Tooth
on inner margin of mandibles in dorsal view. 30, antennal scapes and hairs on leading edge of scape in full-face
view. 31, Lateral view. 32, Dorsal view. 33, Lateral view of mesosoma. 34, Dorsal view of mesosoma. 35, Dorsal
view of waist segments (petiole and postpetiole). 36, Dorsal view of postpetiole and first gastral tergite.
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MODIFIED VERSION OF KEY IN BOLTON (2000)
In Bolton’s (2000) key, Strumigenys acarai will not key out to any of the known species. The key for
the species of Strumigenys of the Neotropics can be modified as below to include S. acarai.
Numbering of couplets follows Bolton (2000).
48. Cephalic dorsum with two pairs of short erect hairs that differ from other cephalic
ground-pilosity, one pair close to occipital margin, other close to highest point of
vertex. Ventral surface of petiole with curtain or fringe of spongiform tissue, or at
least with spongiform lobes linked by carina . . ....... couplet 49 of Bolton (2000)
Figs 26–36. Continued.
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– Cephalic dorsum without or with one pair of short erect hairs that differs from other
cephalic ground-pilosity, when one present it is close to occipital margin. Ventral
surface of petiole without spongiform tissue, sometimes with rounded or angular
anteroventral cuticular process . . ..... 52a (different to couplet 52 in Bolton 2000)
52a. Mandible with minute inconspicuous denticle close to midlength . . . . acarai new species
– Mandible with 1 or 2 very conspicuous spiniform preapical teeth, distal one in apical
third, proximal one close to midlength .............. couplet 52 in Bolton (2000)
Strumigenys waiwai Sosa-Calvo, Schultz,
and LaPolla, n. sp.
(Figs 40–47)
Material examined.—Holotype: worker, labeled
‘‘GUYANA: Upper Takutu-Upper Essequibo,
Acarai Mountains, camp edge Kamoa River,
394 m., 58u49.9299W, 1u32.7869N; 22.x.2006; J.
Sosa-Calvo,T.R. Schultz;1uforest; leaf-litter
sample. (TRS 061022-LS04)’’ USNM ENT
No. 00537291. (UGBC). Paratypes: 2 workers,
same locality as in holotype. USNM ENT
No. 00537290, 00537292; 1 worker, labeled
‘‘GUYANA: Upper Takutu-Upper Essequibo,
Acarai Mountains, camp edge Kamoa River,
530 m., 58u50.2999W, 1u33.0469N; 24.x.2006; J.
Sosa-Calvo,T.R. Schultz,C.J. Marshall,R. Wil-
liams;1uforest; leaf-litter sample. (JSC 061024-
LS10)’’ USNM ENT No. 00537293. (USNM).
Diagnosis (worker).—Small (TL 1.35–
1.45); cephalic margin with multi-furcate
hairs; leading edge of antennal scapes at
least with one hair that curves towards
base of scape; eyes small, consisting of two
Figs 37–39. Automontage images of the holotype worker of Strumigenys acarai, new species. 37, Full-face view.
38, Lateral view. 39, Dorsal view.
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or three ommatidia; inner margin of
mandibles with a pair of spiniform teeth
and a minute but conspicuous pair of teeth
at midlength of mandibles; ventral margin
of petiole with angular ventral process. In
some workers (paratypes) ventral process
of petiole very reduced.
Description (worker).—Head: leading
edge of antennal scapes with at least one
hair curving toward base of antennal
scape; hairs on leading edge of antennal
scapes narrowly spatulate or simple; inner
margin of mandibles with pair of preapical
spiniform teeth close to apicodorsal tooth
and minute but conspicuous pair of teeth
at midlength of mandibles; anterior margin
of clypeus slightly concave (Figs 40, 42);
dorsum of clypeus finely reticulate; dor-
sum of head markedly areolate and with
multi-furcate hairs on posterior occipital
portion (Figs 40–41, 43); upper margin of
scrobes with row of simple hairs that curve
anteriorly and with two flagellate hairs,
one of which is in apicoscrobal position;
eyes very reduced, with 2 or 3 ommatidia;
ocular carina weakly developed, short and
not reaching level of eyes; cephalic dor-
sum, in profile, with 2 pairs of inconspic-
uous erect simple hairs, very difficult to see
and perhaps fragile and easily lost but
differing from bifurcating pilosity that
surrounds them. Mesosoma: dorsum of
promesonotum, propodeum, and declivity
of propodeum strongly areolate; dorsum of
pronotum with elongate pair of hairs in
addition to those at humeri; humeral hair
flagellate; promesonotal spiracle in dorsal
view projecting laterally, giving pronotum
wider appearance and mesonotum and
propodeum narrower appearance; mesono-
tum with pair of elongate hairs; sides of
pronotum and anepisternum strongly areo-
late; mesopleuron and metapleuron mostly
smooth and shining; dorsum of promeso-
notum and propodeum with simple sub-
decumbent hairs; propodeal spines minute
and acute, subtended by broad lamella on
declivity. Metasoma: dorsum of peduncle,
disc, and sides of petiole strongly areolate;
in lateral view, petiole with long ventral
process. In one worker (paratype) ventral
process reduced to small tooth (Fig. 43);
petiole, in lateral view, subquadrate; sides
of petiole, in dorsal view, with conspicuous
triangular crest; postpetiole, in lateral view,
with large ventral spongiform lobes; disc of
postpetiole with some longitudinal rugae;
areas between rugae smooth and shining;
dorsum of postpetiole with decumbent
hairs; first gastral sternite with pad of
spongiform tissue; first gastral tergite
smooth and shining, with some conspicu-
ous longitudinal basigastral costulae, barely
as long as disc of postpetiole; first gastral
tergite mostly with subdecumbent and
decumbent hairs and some erect hairs
(lacking in some paratype specimens. It is
probable that these hairs are very fragile
and lost easily).
Measurements: holotype (and paratypes):
GL 50.31 (0.28–0.31), HL 50.33 (0.31–
0.34), HW 50.26 (0.25–0.26), ML 50.18
(0.18–0.19), PL 50.17, PPL 50.08 (0.08–
0.09), PW 50.16 (0.14–0.16), SL 50.21
(0.19–0.21), TL 51.44 (1.35–1.45), WL 5
0.36 (0.32–0.36). Indexes: CI 579 (76–80),
MI 555 (53–58), PI 548 (47–51), SI 581
(77–82). (n 54)
Gyne and male.—Unknown
Etymology.—This species is named after
the Wai-Wai indigenous people, who de-
pend on the area where we collected this
species for their sustenance. Without their
guidance, support, and permission to con-
duct research on their land, this work
would not have been possible.
Comments.—Strumigenys waiwai is most
similar to members of the Neotropical
silvestrii-group. Strumigenys waiwai shares
with most of the 18 known species in this
group the following characters: (i) the
small size (HL 0.31–0.34, HW 0.25–0.26,
TL 1.35–1.45, WL 0.32–0.36. In members of
the silvestrii-group HL 0.36–0.52, HW 0.28–
0.44, TL 1.5–2.2, WL 0.36–0.56); (ii) the
absence of intercalary tooth between the
apicodorsal and apicoventral teeth in the
apical fork of the mandibles (this character
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state is shared with all the species in the
group, except for S. xochipili Bolton from
Mexico, which possesses a single interca-
lary tooth); (iii) the presence, on the inner
margin of mandibles, of a spiniform pair of
preapical teeth close to the apicodorsal
tooth of the apical fork and, in addition, a
minute pair of denticles on the midlength
of the mandibles that may be difficult to
see; (iv) the antennal scapes short to
moderate (SI 76–80. In members of the S.
silvestrii species group the SI 62–91), and
with some hairs on the leading edge of the
antennal scape that are curved toward the
base of the scape; (v) the eyes very small,
commonly formed by 1–3 ommatidia in
total (some members of the S. silvestrii
species group with 6 or more ommatidia);
Figs 40–47. Scanning electron micrograph of a paratype worker of Strumigenys waiwai, new species. 40, Head
and mandibles in full-face view. 41, Cephalic capsule in full-face view. 42, Mandibles in dorsal view. 43, Lateral
view. 44, Dorsal view. 45, Dorsal view of mesosoma. 46, Waist segments in dorsal view. 47, Postpetiole and first
gastral tergite in dorsal view.
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(vi) the preocular carina short or weakly
developed, ending before level of the eye;
(vii) the propodeum, in profile, usually with
a triangular pair of teeth that are subtended
by a lamella or carina that extends down the
declivity; and (viii) ventral surface of petiole
lacking spongiform tissue instead with a
small, but conspicuous crest or ventral
process (members of the silvestrii-group
usually lack spongiform tissue on ventral
margin of petiole except for the species S.
nastata Bolton, S. perdita Bolton, and S.
calamita Bolton).
Variations in the presence of standing
erect hairs on the cephalic dorsum were
observed in the specimens studied (holo-
type and paratypes). In the material exam-
ined, some workers of S. waiwai have the
two pairs of erect simple hairs on the
dorsum of head that differ from the
cephalic ground-pilosity, of which one pair
is located close to occipital margin and the
other is located close to the highest point of
vertex. Among the variations observed in
other specimens are: the two pairs of
standing hairs are present, but curving at
the tips, or only one pair of hairs is visible,
or the hairs are difficult to see, or the hairs
are missing. Apparently these hairs are
very fragile and can be easily lost; therefore
specimens may appear to have no hairs.
Within the silvestrii-group, only individ-
uals in the species S. calamita,S. nastata,S.
perdita, and S. timicala Bolton, all endemic
to Central America, share with individuals
of S. waiwai the presence of two pairs of
erect hairs on the cephalic dorsum, but
these species differ from S. waiwai by
having a fringe or curtain of spongiform
tissue on the ventral margin of the petiole,
whereas S. waiwai has an angular crest or
small ventral process. In addition, S. waiwai
differs from: S. nastata by having the
antennal scape without a projecting nar-
row cuticular lamella that arises proximal
to the subbasal bend; S. timicala by having
the preapical tooth of the mandible sepa-
rated from the apicodorsal tooth by a
distance twice its length, rather than hav-
ing the preapical tooth very close to the
apicodorsal tooth; S. calamita and S. perdita
by having the first gastral tergite generally
with subdecumbent or decumbent simple
hairs (in some specimens it is possible to
see, in addition, a few erect simple hairs)
rather than entirely short stout hairs that
are remiform to claviform (in S. calamita)or
simple erect and stiff (in perdita); and from
all four species and any other species in the
S. silvestrii-group by: (i) having the dorso-
lateral margin of the head with two freely
laterally projecting elongate or short fla-
gellate hairs, one of which is located at the
level of the vestigial eye and the other the
apicoscrobal hair. This character state is
also shared with S. lanuginosa but these
hairs are shorter in S. waiwai than in S.
lanuginosa; (ii) having hairs on the upper
margins of the antennal scrobe simple and
curving anteriorly rather than spoon-
Figs 40–47. Continued.
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shaped, spatulate, or narrowly spatulate
and curving anteriorly (except for perparva
in which case these hairs are posteriorly
curved); and (iii) the cephalic ground-
pilosity composed of short erect or sub-
decumbent multifurcated hairs rather than
spoon-shaped, spatulate, or narrowly spat-
ulate hairs.
MODIFIED VERSION OF KEY IN BOLTON (2000)
In Bolton’s (2000) key, Strumigenys waiwai keys out to S. perdita. The key for the species of
Strumigenys of the Neotropics can be modified as below to properly include S. waiwai. Numbering
of couplets follows Bolton (2000).
47. In full-face view upper scrobe margin with a row of 4–5 broadly spatulate to spoon-
shaped hairs that are curved posteriorly .......................... perparva
– In full-face view upper scrobe margin with row of simple or spatulate to spoon-shaped
hairs that are all curved anteriorly . . . .............. couplet 48 in Bolton (2000)
48. Cephalic dorsum with two pairs of short erect hairs, one pair close to occipital margin,
the other close to highest point of vertex. Ventral surface of petiole with curtain or
fringe of spongiform tissue, or at least with spongiform lobes linked by carina. If
spongiform tissue reduced to angular anteroventral process present, then
dorsolateral margin of head with two freely laterally projecting short flagellate
hairs, one at level of the vestigial eye, the other the apicoscrobal . ........... 49
– Cephalic dorsum without or with one pair of short erect hairs, when one is present it is
close to occipital margin. Ventral surface of petiole without spongiform tissue,
sometimes with rounded or angular anteroventral cuticular process. Dorsolateral
margin of head without projecting flagellate hairs or with single hair, in
apicoscrobal position . . .......................... couplet 52 in Bolton (2000)
49. Distal preapical tooth conspicuous and obviously spiniform, located markedly
proximal of the apicodorsal tooth and at about right angle to long axis of the
mandible. Distal preapical teeth of opposing mandibles so long that their apices
meet or even slightly overlap when mandibles fully closed. Mandibles always with
small denticle just proximal of the inner midlength . . . ................... 50
– Distal preapical tooth small, thorn-like and not obviously spiniform, located very close
to the apicodorsal tooth and inclined toward it. Distal preapical teeth of opposing
mandibles so short that their apices are widely separated when mandibles fully
closed. Mandible usually without trace of denticle proximal to inner midlength but
rarely vestigial denticle visible . . ................................ timicala
50. Leading edge of scape at subbasal bend with projecting convex cuticular lamella;
lamella originates close to scape base and terminates just distal of the bend. Distal
preapical tooth about same distance from proximal preapical denticle as it is from
apicodorsal tooth . ............................................ nastata
– Leading edge of the scape at subbasal bend without projecting convex cuticular
lamella. Distal preapical tooth closer to apicodorsal tooth than it is to proximal
preapical denticle ................................................ 51a
51a. Leading edge of antennal scape with spoon-shaped or narrowly spatulate hairs. In
full-face view upper scrobe margin with row of spatulate to spoon-shaped hairs.
Cephalic ground-pilosity spoon-shaped or spatulate . . . . couplet 51 of Bolton (2000)
– Leading edge of antennal scape with simple or filiform hairs. In full-face view, upper
scrobe margin with a row of simple or filiform hairs. Cephalic ground-pilosity
multifurcated ...................................... waiwai new species
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ACKNOWLEDGMENTS
We would like to thank Barry Bolton for confirming
the new species. We thank George Else, Suzanne
Lewis, Christine Taylor (BMNH), and Carlos Roberto
Branda
˜o (MZSP) for specimen loans. Ted Suman
(USNM) sorted and prepared the specimens, Scott
Whittaker (USNM) assisted with the scanning elec-
tronic micrographs, and Eugenia Okonski (USNM)
databased and labeled the specimens. For corrections
and comments on earlier versions of the manuscript
we thank Matt Buffington, David Furth, Victor H.
Gonzalez, Akito Kawahara, Robert Kula, and John T.
Longino. Claudia M. Ortiz and Monica Pava-Ripoll
read and commented on the Spanish-language ab-
stract. We thank Brian Fisher and an anonymous
reviewer for comments that greatly improved the
manuscript. This project was supported in part by
NSF DEB 0110073 and DEB 0431330 to TRS, by a
National Geographic Society Committee for Research
and Exploration grant to JSL and TRS, by the
Smithsonian Institution USS Restricted Endowment
Fund grant to TRS, and by the Smithsonian Institu-
tion’s Biological Diversity of the Guiana Shield
Program (BDG). This manuscript is number 158 in
the BDG Program’s publication series.
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Appendix 1
Map of Guyana with locations of places sampled, modified from LaPolla et al. (2007).
Legend (Abbreviations follow those of Appendix 1): (1) CWC; (2) MAB, MAD, MAF,
MAU; (3) MHC; (4) IFR; (5) KMM; (6) ARC, ANR
1
, ANR
2
; (7) KRC.
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Appendix 2. Dacetine ant species currently known from Guyana.
Taxon Locality Notes/Reference
Acanthognathus brevicornis
M.R. Smith
ARC, ANR
2
, CWC, KRT, MAB New record
A. lentus Mann ANR
2
, IFR, KRT New record
A. ocellatus Mayr ARC, KRT New record
A. stipulosus?
Brown & Kempf
ANR
1
New record
Daceton armigerum
(Latreille)
IFR, Essequibo River, Rupununi
Savannah, Tukeit
Bolton 2000; Fernandez & Sendoya
2004; Wheeler 1916; this study
Pyramica alberti
(Forel)
ANR
2
, Kartabo, KRC, KRT Bolton 2000; Fernandez & Sendoya
2004; this study
P. auctidens Bolton ANR
1
, KMM, KRC, KRT New record
P. beebei (Wheeler) ARC, ANR
1
, IFR, KRC, KRT, MAB New record
P. cincinnata (Kempf) ANR
1
, ANR
2
, MAB New record
P. crassicornis (Mayr) ANR
1
, ANR
2
, Guyanas, KRC, KRT Kempf 1972; Bolton 2000;
Fernandez & Sendoya 2004;
this study
P. dahlanae n. sp. CWC, MHC New species
P. denticulata (Mayr) ARC, ANR
1
, ANR
2
, Berbice Dubulay
Ranch, CWC, IFR, KMM, KRC, KRT,
MAB, MHC, Morabukea, R. Mazaruni
Forest
Bolton 2000; Fernandez & Sendoya
2004; this study
P. depressiceps (Weber) Kartabo Bolton 2000; Fernandez & Sendoya
2004
P. glenognatha Bolton IFR, KMM, MAF, MAU New record
P. inusitata (Lattke) KRT New record
P. mariae n. sp. MAU New species
P. metopia (Brown) ARC, KRT New record
P. metrix Bolton ANR
1
, ANR
2
New record
P. mirabilis (Mann) ARC New record
P. stenotes Bolton MHC New record
P. subedentata (Mayr) ARC, ANR
1
, ANR
2
, IFR, KMM, KRC, KRT,
MAB, MHC
New record
P. thaxteri (Wheeler) MAB New record
P. urrhobia Bolton ARC New record
P. villiersi (Perrault) ANR
1
, IFR, KMM, KRC, KRT, MHC New record
Strumigenys acarai ANR
1
New species
S. cordovensis Mayr ARC, ANR
2
New record
S. cosmostela Kempf ANR
2
, MAB New record
S. dolichognatha
Weber
IFR, Kartabo, MAB, MHC Bolton 2000; Fernandez & Sendoya
2004; this study
S. dyseides Bolton CWC, KRC, MHC New record
S. elongata Roger ANR
1
, ANR
2
, CWC, IFR, KMM,
KRT, MAB, MHC, Morabukea,
Bolton 2000; Fernandez & Sendoya
2004; this study
S. godmani Forel Kartabo Bolton 2000; Fernandez & Sendoya
2004
S. pariensis Lattke &
Goitı
´a
ARC, ANR
1
, ANR
2
, KRC, KRT New record
S. perparva Brown ARC, ANR
1
, ANR
2
, Berbice Dubulay
Ranch, CWC, IFR, KMM, KRC, KRT,
MAB, MHC
Bolton 2000; Fernandez & Sendoya
2004; this study
S. precava Brown ANR
2
, Between R. Cuyuni & R.
Mazaruni, Kamakusa, KRC, MHC,
MAD
Bolton 2000; Fernandez & Sendoya
2004; this study
S. royi n. sp. KRC, KRT New species
S. ruta Bolton KMN New record
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Appendix 3
KEY TO DACETINI KNOWN FROM GUYANA
(NOTE: This key is an adaptation of that of Bolton [2000] to include only the species that occur in
Guyana. This key also includes modifications from Brown and Kempf [1969]; Bolton [1994])
1. Antenna 11–segmented ............................................... 2
– Antenna 4 to 6–segmented . . ........................................... 6
2(1). In lateral view, antennal scape passes below eye when in resting position. Propodeal
node bidentate. Palpal formula 5,3 . ..................... Daceton armigerum
– In lateral view, antennal scape passes above eye when in resting position. Propodeal
node unarmed. Palpal formula 0,1 . ................................... 3
3(2). Preapical area of masticatory margin of mandibles with irregular denticles . . . . . .
........................................... Acanthognathus brevicornis
– Preapical area of masticatory margin of mandibles lacking denticles . . . .......... 4
4(3). Node of petiole with convex anterior face and flat, sloping posterior face, not evenly
rounded . ................................... Acanthognathus stipulosus
– Node of petiole low and evenly rounded when seen in profile . . . .............. 5
5(4). Fossae on posterior half of dorsum of head smaller, mostly separated by flat, smooth
spaces . . . .................................... Acanthognathus ocellatus
– Fossae on posterior half of dorsum or head large, mostly contiguous or separated by
single, simple longitudinal rugulae . .................. Acanthognathus lentus
6(1). Mandibles inserted on sides of anterior cephalic margin and converging towards apex
when closed. Inner margin of mandibles generally with numerous teeth or
denticles . .............................................. 7(Pyramica)
– Mandibles inserted on median portion of anterior cephalic margin and diverging
towards apex when closed. Inner margin of mandibles with 0–2 preapical
teeth ............................................... 25 (Strumigenys)
Taxon Locality Notes/Reference
S. silvestrii Emery ANR
2
New record
S. smilax Bolton ARC New record
S. smithii Forel ANR
2
New record
S. trinidadensis
Wheeler
ANR
2
, KRC, MHC New record
S. trudifera Kempf
& Brown
ANR
2
, KRC, KRT New record
S. waiwai n. sp. KRC, KRT New species
Abbreviations for localities:ARC: Upper Takutu-Upper Essequibo, Acarai Mountains, Romeo Camp, 58u56.7899W,
1u23.1479N, elev. 290 m; ANR
1
: Upper Takutu-Upper Essequibo, Acarai Mountains, New Romeo Camp,
58u57.8289W, 1u19.9389N, elev. 1069 m; ANR
2
: Upper Takutu-Upper Essequibo, Acarai Mountains, New Romeo
Camp, 58u57.499W, 1u20.8549N, elev. 750 m; CWC: Calm Water Creek, 58u37.169W, 6u28.069N, elev. 20 m; IFR:
Iwokrama Forest Reserve Whitewater Camp, 58u50.9929W, 4u43.8909N, elev. 60 m; KMM: Kanuku Mountains
near Moco-Moco Falls, 59u38.3769W, 3u17.2979N, elev. 224 m; KMN: Kanuku Mountains near Nappi Creek
Camp, 59u33.9639W, 3u21.0189N, elev. 128 m; KRC: Upper Takutu-Upper Essequibo, Kamoa River Camp,
58u49.9299W, 1u32.7869N, elev. 530 m; KRT: Upper Takutu-Upper Essequibo, Kamoa River top mountain,
58u50.2999W, 1u33.0469N, elev. 717 m; MAB: Base Camp Mount. Ayanganna, 59u55.4869W, 5u20.0639N, elev.
732 m; MAD:Dicymbe Camp Mount Ayanganna, 59u54.6329W, 5u17.7609N, elev. 717 m; MAF: Falls Camp Mount
Ayanganna, 59u57.5639W, 5u22.3329N, elev. 1134; MAU: Upper Forest Mount Ayanganna, 59u57.9699W,
5u22.4839N, elev. 1300 m; MHC: Mabura Hill, 58u41.9829W, 5u09.3139N, elev. 64 m. ‘‘New record’’ refers to a new
record for Guyana.
Appendix 2 Continued.
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7(6). In full-face view, mandibles sublinear to linear, elongated and narrow; when closed,
mandibles contacting each other only in apical halves or less of their lengths; either
with an elongate space between mandibles or their inner margins convex so that
margins touch, or nearly touch, near midlength . . ........................ 8
– In full-face view, mandibles either short and trap-like, or triangular to elongate-
triangular; when closed contacting through most or all of their exposed length,
lacking an elongate space between mandibles or at most with diastema basally
between basal lamella and basal tooth . ................................ 15
8(7). Disc of postpetiole smooth or with weak longitudinal costulae in parts, never densely
reticulate-punctate ................................... Pyramica dahlanae
– Disc of postpetiole densely reticulate-punctate over most or all of its surface . . . . . . 9
9(8). Inner margin of mandible with clearly defined submedian tooth or distinctly enlarged
denticle at or just distal of midlength of mandible, this tooth or denticle obviously
larger than any other preapical dentition that may be present distal to it, if two
distinctive enlarged teeth present, distal located at about the apical third and
proximal in basal third of mandible length. Labral lobes very long and slender,
trigger hairs at apices of lobes short . . ................................ 10
– Inner margin of mandible without a tooth or distinctly enlarged denticle at or near the
midlength that is obviously larger than any other preapical dentition that may be
present distal to it, if two distinctive enlarged teeth present, both of them closer to
preapical dentition than to midlength of mandible. Labral lobes short, trigger hairs
at apices of lobes long . ............................................ 13
10(9). Pronotal humeral hair long and flagellate. Mesonotum with single pair of long
flagellate hairs . . . .................................... Pyramica metopia
– Pronotal humeral hair sometimes absent usually present, short-spatulate to filliform,
never flagellate. Mesonotum without flagellate hairs . . . ................... 11
11(10). Scape narrow basally; anterior margin of scape beyond base abruptly expanded and
almost lobate at subbasal angle, scape distinctly widest at this point. Dorsolateral
margin of head lacking apicoscrobal hair. Postpetiole, in profile, swollen or
subglobular . ..................................... Pyramica crassicornis
– Scape gradually broadening from base to apex; anterior margin convex but not
abruptly expanded at subbasal angle, scape widest at or near its midlength.
Dorsolateral margin of head with an apicoscrobal hair of some form. Postpetiole, in
profile, not swollen nor subglobular . . ................................ 12
12(11). Inner margin of mandible with single enlarged preapical tooth, located near midlength;
other minutely denticles present, but without a second equally sized tooth. Larger
species (HL 0.61–0.63, HW 0.41–0.43, AL 0.58–0.60) ............ Pyramica stenotes
– Inner margin of mandible with two enlarged preapical teeth of approximately equal
size; in addition to other minutely denticles. Smaller species (HL 0.50–0.52, HW
0.34–0.36, AL 0.46–0.50) ............................... Pyramica auctidens
13(9). In lateral view, dorsum of mesosoma with 4–6 pair of stout remiform standing hairs
(not including those at humeri). Mandibles short (MI 49–54). In full-face view, inner
margins of mandibles convex and, when entirely closed, touching at about
midlength . . ..................................... Pyramica subedentata
– In lateral view, dorsum of mesosoma with single pair of standing hairs (not including
those at humeri). Mandibles larger (MI 72–85). In full-face view inner margins of
mandibles more or less straight to shallowly concave . . ................... 14
14(13). Inner margin of mandibles with 5–10 preapical denticles of similar size. Metapleuron
entirely densely reticulate. Peduncle of petiole short, PI 38–42 . . . Pyramica denticulata
– Inner margin of mandibles with 3–4 preapical denticles, two of which are distinctly
much larger than rest. Metapleuron in most of its surface smooth and shining.
Peduncle of petiole elongate, PI 48–49 . ..................... Pyramica mariae
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15(7). With head in full-face view, anterior margin of scape with projecting curved hairs, of
which one or more, distal to subbasal bend, distinctly curve toward base of scape.
These hairs may be simple, spatulate, spoon-shaped, or wire-like . . . ......... 16
– With head in full-face view, anterior margin of scape without projecting hairs that
distinctly curve toward base of scape. Scape edge may have elongate simple
straight or flagellate projecting hairs present; or may have entirely anteriorly or
apically directed short hairs; or lacking hairs . . ......................... 21
16(15). Pronotal humeral hair present, may be filiform, flagellate, remiform, or clavate;
humeral hair always distinctly differentiated from any other pilosity that may be
present on dorsal pronotum . . ...................................... 17
– Pronotal humeral hair absent; humerus without a hair that is distinctly differentiated
from any other pilosity that may be present on dorsal pronotum . . . ......... 20
17(16). Ventral surface of petiole in profile with spongiform tissue reduced to absent;
discounting anterior subpetiolar process (if present) usually with narrow non-
spongiform cuticular carina, but if weakly spongiform strip occurs then its
maximum depth only fraction of depth of peduncle. Disc of postpetiole usually
sculptured at least in part, only rarely mostly smooth ..................... 18
– Ventralsurface of petiole in profile with deep, conspicuous andvery obviously spongiform
curtain, its maximum depth at least half that of peduncle and usually more. Disc of
postpetiolecompletelyunsculpturedandglassysmooth ............ Pyramica alberti
18(17). Metapleuron and side of propodeum entirely reticulate-punctate .............. 19
– Metapleuron and side of propleuron mostly or entirely smooth and shinning ....
................................................ Pyramica cincinnata
19(18). Pronotal humeral hair elongate and freely projecting, slightly flattened apically and
more or less straight. Scape in dorsal view slender, broadest point distinctly distal
of midlenght. Anterior margin of clypeus very shallowly convex in full-face view.
Disc of postpetiole not entirely densely reticulate-punctate ..... Pyramica urrhobia
– Pronotal humeral hair very short, clavate. Scape in dorsal view broad and flattened,
broadest point proximal of midlenght, at or just distal of subbasal bend. Anterior
margin of clypeus transverse to very shallowly concave in full-face view. Disc of
postpetiole entirely densely reticulate-punctate . .............. Pyramica metrix
20(16). Promesonotum, side of mesosoma, and disc of postpetiole finely reticulate-punctate.
Head in profile incredible dorsoventrally flattened; at eye level depth of head
capsule scarcely more than twice vertical diameter of the eye. Ventral margin of
petiole lacking curtain of lamellate or spongiform tissue . . . . Pyramica depressiceps
– Promesonotum and side of mesosoma smooth and shining, disco of pospetiole not
reticulate-punctate. Head in profile not strongly dorsoventrally flattened; at eye
level depth of head capsule distinctly more than twice vertical diameter of eye.
Ventral margin of petiole with lamellate curtain that extends entire length of
segment . . .......................................... Pyramica thaxteri
21(15). With head in full-face view dorsolateral margin behind levelof eye with laterally projecting
hairs present; at least an apicoscrobal hair but often more along margin . . .......... 22
– With head in full-face view dorsolateral margin behind level of eye without laterally
projecting hairs of any form; any hairs that do occur are minute and closely
appressed, not at all projecting ...................................... 24
22(21). Midline of clypeal dorsum raised into a high-arched thick longitudinal crest that
extends entire length of sclerite. With postpetiole in profile ventral spongiform lobe
either completely absent or reduced to minute triangular vestige anteriorly on
sternite . . ......................................... Pyramica inusitata
– Midline of clypeal dorsum not raised into a high longitudinal crest that extends length
of sclerite. With postpetiole in profile ventral spongiform lobe fully developed,
basally extending length of sternite and conspicuously convex apically . ...... 23
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23(22). Dorsal surface of petiole without erect cuticular lamella on peduncle and anterior face
of node. Dorsolateral margin of propodeum without an erect lamella on each side;
lamella on propodeal declivity narrow to cariniform, in profile its maximum width
much less than length of postpetiole disc . . . ............... Pyramica villiersi
– Dorsal surface of petiole with erect cuticular lamella that extends alongpeduncleand
ascends anterior face of node, terminating just behind anterodorsal angle. Dorsolateral
margin of propodeum with a tall erect cuticular lamella on each side that is continuous
with extremely broad lamella on declivity; in profile maximum width of lamella on
declivityequaltolengthofpostpetioledisc ................... Pyramica mirabilis
24(21). Dorsal outline of clypeus angled down at about 45 degrees to line of vertex. Ventral
surface of petiole with well-developed curtain, of spongiform or translucent
lamellar tissue, that runs most or all of the length of the segment. Head elongate (CI
68–70) .............................................. Pyramica beebei
– Dorsal outline of clypeus not angled down from line of vertex. Ventral surface of
petiole lacking curtain of spongiform or lamellar tissue. Head short and broad (CI
91–96) .......................................... Pyramica glenognatha
25(6). Anterior margin of scape with all hairs curved or inclined toward apex of scape,
without hairs that curve toward base of scape, and without a series of hairs at right-
angles to long axis of scape shaft .................................... 26
– Anterior margin of scape either with one to many hairs that distinctly curve toward
base of scape, or rarely with hairs that are at right angles to long axis of scape shaft;
never with all hairs obviously curved or inclined toward apex of scape ....... 29
26(25). Mandibles relatively short, MI ,75. Bulla of femoral gland located in apical quarter of
dorsum of each leg; each bulla usually appears as pale oval patch, less commonly
as short streak . . . ................................................ 27
– Mandibles relatively long MI .85. Bulla of femoral gland located close to midlength on
dorsum of each leg; each bulla appears as pale elongate streak or as oval patch ... 28
27(26). Mandibles short and stout (MI 41–48), broad and powerful, outer margins strongly
bowed outwards. Declivity of propodeum in profile with tooth or spine above and
triangular lobe or tooth below, two linked by lamella. First gastral tergite glassy
smooth behind minute to vestigial basigastral costulae . .... Strumigenys godmani
– Mandibles long and linear (MI 57–60), thick throughout most of their length and
abruptly narrowing just before apex by sudden oblique divergence of inner margin,
outer margins straight to slightly convex. Declivity of propodeum in profile with
single tooth or spine, lacking second tooth or lobe below. First gastral tergite finely
reticulate-substrigulate with some verrucose sculpture confined to basigastral
area . . .............................................. Strumigenys royi
28(26). In full-face view distal preapical tooth of mandible is closer to proximal preapical
tooth than it is to apicodorsal tooth . . . ............. Strumigenys dolichognatha
– In full-face view distal preapical tooth of mandible is closer to apicodorsal tooth than it
is to proximal preapical tooth . . . ................... Strumigenys cordovensis
29(25). Mandible without intercalary teeth or denticles that arise between apicodorsal and
apicoventral teeth, nor that arise from dorsal base of apicoventral tooth ....... 30
– Mandible with 1 or 2 intercalary teeth or denticles that arise between apicodorsal and
apicoventral teeth, or that arise from dorsal base of apicoventral tooth . ....... 40
30(29). Mandible without preapical teeth or denticles . . ........................... 31
– Mandible with 1 or 2 preapical teeth or denticles . . . ....................... 32
31(30). Hairs of first gastral tergite flagellate, not flattened and ribbon-like through most of
their length . ..................................... Strumigenys elongata
– Hairs of first gastral tergite flattened and ribbon-like through most of their length,
narrowly flagellate only in apical section . . . ............ Strumigenys pariensis
32(30). Mandibles very long, MI .100 ......................... Strumigenys trudifera
– Mandibles much shorter, MI ,75 ...................................... 33
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33(32). With head in profile preocular carina extends back almost to apex of scrobe, well
beyond level of minute eye. Bulla of femoral gland proximal of midlength on
dorsum of middle leg, very conspicuous. Scape relatively long, SI 111-112 ....
................................................. Strumigenys smilax
– With head in profile preocular carina terminates at level of eye. Bulla of femoral gland
distal of midlength on dorsum of middle leg or inconspicuous. Scape shorter, SI ,
100 ........................................................... 34
34(33). Large species (HL 0.86–1.02, ML 0.50–0.56, AL 0.80–1.00). Ventrolateral margin of head
in front of eye, and side of head above it, deeply concave; margin and side appear
excavated or constricted in oblique dorsal view ........... Strumigenys precava
– Smaller species (HL 0.39–0.45, ML 0.20–0.30, AL 0.36–0.47). Ventrolateral margin of
head in front of eye, and side of head above it, not deeply concave; margin and side
do not appear excavated or constricted in oblique dorsal view . ............. 35
35(34). In full-face view upper scrobe margin with row of 4–5 broadly spatulate to spoon-
shaped hairs that curve posteriorly . ................... Strumigenys perparva
– In full-face view upper scrobe margin with row of simple, or narrowly spatulate to
spoon-shaped hairs that all curve anteriorly . . . ......................... 36
36(35). Mandible with single spiniform preapicaltooth, in distal third, or with tooth in this
position and denticle, that may be minute and difficult to see, close to midlength . . . 37
– Mandible with minute inconspicuous denticle close to midlength lacking second tooth
of any form . . . ..................................... Strumigenys acarai
37(36). Leading edge of antennal scape with spoon-shaped or spatulate hairs. In full-face view
upper scrobe margin with row of spatulate to spoon-shaped hairs, and with
apicoscrobal hair only. Cephalic ground-pilosity spoon-shaped or spatulate .... 38
– Leading edge of antennal scape with narrowly spatulate or simple hairs. In full-face
view upper scrobe margin with row of simple hairs and with two flagellate hairs,
one of which is apicoscrobal hair. Cephalic ground-pilosity multi-furcate .....
................................................ Strumigenys waiwai
38(37). Hairs on first gastral tergite short and stout, broadly spatulate or remiform; elongate
slender fine hairs absent or restricted to transverse row at extreme apex of
sclerite . . . ....................................... Strumigenys silvestrii
– Hairs on first gastral tergite elongate and slender, finely filiform to flagellate, or
flexuous; short stout spatulate or remiform hairs entirely absent . . . . . . ...... 39
39(38). Mandibles relatively long, MI .60. Disc of postpetiole smooth and shinning.
Mesonotum without pair of erect flagellate hairs . . . ....... Strumigenys dyseides
– Mandibles relatively short, MI ,60. Disc of postpetiole densely punctate to reticulate-
punctate. Mesonotum with pair of erect flagellate hairs . . ...... Strumigenys ruta
40(29). Apical fork of mandible with single intercalary tooth or denticle that arises between apico-
dorsal and apicoventral teeth, or arises from dorsal surface of apicoventraltooth ........ 41
– Apical fork of mandible with two intercalary teeth or denticles that arise between
apicodorsal and apicoventral teeth; frequently represented by distinct intercalary tooth
accompaniedbylessconspicuousorminutedenticle ....... Strumigenys cosmostela
41(40). First gastral tergite very finely and densely longitudinally striolate-costulate and
opaque. Apicoscrobal hair, pronotal humeral hair and standing hairs on
mesonotum all flagellate. Entire body dull yellow to brownish-yellow, gaster not
contrasting with head and alitrunk . ................ Strumigenys trinidadensis
– First gastral tergite glassy smooth. Apicoscrobal hair, pronotal humeral hair and
standing hairs on mesonotum all stiff, simple to weakly remiform. Head and
alitrunk reddish brown to brown, gaster blackish brown to black, both
contrasting . . . ..................................... Strumigenys smithii
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