The Higher Classification of the Ant Subfamily Ponerinae (Hymenoptera: Formicidae), with a Review of Ponerine Ecology and Behavior
Author
Schmidt, C. A.
Author
Shattuck, S. O.
text
Zootaxa
2014
2014-06-18
3817
1
1
242
journal article
5350
10.11646/zootaxa.3817.1.1
d66f1b27-5891-4fa5-96e0-f75cb3ec2445
1175-5326
10086256
A3C10B34-7698-4C4D-94E5-DCF70B475603
Euponera
Forel
Figs 11
,
12
Euponera
Forel, 1891: 126
(as subgenus of
Ponera
). Type-species:
Ponera
(
Euponera
)
sikorae
Forel, 1891: 127
; by monotypy.
Gen. rev.
Euponera
is a moderately large genus (26 described species) of medium-sized ants occurring in the Afrotropics,
Madagascar
and eastern Asia. Its habits are poorly known.
Diagnosis.
Euponera
species
fall into two groups, the first, related to
E. sikorae
, can be diagnosed by the presence of a shiny integument, basal mandibular pits, cordate frontal lobes, divided mesopleuron, deep metanotal groove, and strong gastral constriction. This combination of characters does not occur in any other ponerine genus. The second set of species, which includes
E. sjostedti
, can be separated from others by the presence of basal mandibular pits, obsolete metanotal groove, elongate or slit-shaped propodeal spiracle, simple subpetiolar process without an anterior fenestra and a prora on anterior margin of first gastral sternite. A shiny integument occurs in some other ponerines, but is absent in most large species. Basal mandibular pits occur in most species of
Brachyponera
and
Cryptopone
. Cordate frontal lobes occur in most members of the
Plectroctena
group as well as in
Bothroponera
(
s.s.
). A divided mesopleuron and deep metanotal groove occur in combination only in some
Brachyponera
,
Hagensia
(in which the mesopleuron is only partially divided), and in
Mesoponera subiridescens
.
Euponera
superficially most closely resembles
Bothroponera
(
s.s.
) and
Pseudoponera
, but differs in the presence of basal mandibular pits. Some
Euponera
species
are also similar to
Cryptopone
, but these differ in having eyes and lacking mesotibial traction setae. They are also similar to
Mesoponera
but are generally smaller in body size with smaller eyes, larger frontal lobes, a wider head and have shorter mandibles.
FIGURE 11.
Worker caste of
Euponera sikorae
: lateral and dorsal view of body and full-face view of head (CASENT0487847, April Nobile and www.antweb.org); world distribution of
Euponera
.
FIGURE 12.
Worker caste of
Euponera antsiraka
: lateral and dorsal view of body and full-face view of head (CASENT0317590, Jean Claude Rakotonirina and www.antweb.org).
Synoptic description.
Worker.
Large (TL
6–10.5 mm
) ants with the standard characters of
Ponerini
. Mandibles triangular, with numerous teeth and a basal pit. Anterior clypeal margin convex or medially emarginate. Frontal lobes moderatel large to large, cordate and closely approximated for most of their length (less close in the
E. wroughtonii
group). Eyes small (3-4 facets in diameter) to moderate in size, located just anterior of head midline (in
E. sikorae
) or anteriorly on sides of head (in most species). Mesopleuron sometimes divided by a transverse groove. Metanotal groove varying from little more than a suture to deeply impressed. Metapleural gland orifice opening laterally in the
P. wroughtonii
group. Propodeal spiracle slit-shaped. Metatibial spur formula (1s, 1p). Petiole with a cuboidal node in most species but scale-like in a few. Girdling constriction between pre- and postsclerites of A4 apparent. Head and body varying from shiny and sparsely punctate, with sparse pilosity and pubescence to finely punctate and with abundant pilosity and scattered to dense pubescence. Color variable, ferrugineous to black.
Queen.
Winged but otherwise similar to workers (Rakotonirina & Fisher, 2013).
Male.
Not
described.
Larva.
Not
described.
Geographic distribution.
Euponera
occurs in Sub-Saharan Africa and
Madagascar
and
India
eastward to
Korea
and
Japan
and south through the
Philippines
to
Indonesia
.
Ecology and behavior.
Collections of
Euponera sikorae
have come from rainforest habitats, but nothing else is known about its ecology or behavior.
Terayama (1999)
reported that
E. sakishimensis
nests in soil and that workers forage on the ground, and K. Masuko observed very small colony sizes (4–
11 workers
) in
E. pilosior
(pers. comm. in Peeters, 1993).
Villet (1994)
studied the colony demographics and reproductive strategy of
E. fossigera
. This species is a generalist predator, forms small colonies (up to
50 workers
), and nests in soil, leaf litter, or rotting wood. Reproduction is performed by a single ergatoid.
Phylogenetic and taxonomic considerations.
Other than
Pachycondyla
itself,
Euponera
has been the focus of the greatest taxonomic lumping within the
Ponerinae
, having at various times housed
Brachyponera
,
Mesoponera
,
Pseudoponera
,
Xiphopelta
(here treated as a junior synonym of
Mesoponera
) and
Hagensia
, all of which (except
Xiphopelta
) we consider to be distinct genera.
Euponera
was originally erected as a subgenus of
Ponera
by
Forel (1891)
to house the single species
E. sikorae
. Emery raised
Euponera
to full genus status (1900a) and described
Brachyponera
(1900a)
and
Mesoponera
(1900b)
as subgenera of
Euponera
. Emery’s treatment was generally accepted by most authors (but see
Bingham, 1903
) until
Wilson (1958c)
moved both
Brachyponera
and
Mesoponera
to full genus status.
Forel (1901a)
moved
Pseudoponera
to subgenus status under
Euponera
, where it generally remained until
Wheeler (1922b)
revived it as a distinct genus (but again see
Bingham, 1903
).
Emery (1911)
treated
Trachymesopus
(now
Pseudoponera
) as a subgenus of
Euponera
, though
Wilson (1958c)
eventually raised it to full genus status.
Arnold (1915)
synonymized
Hagensia
under
Euponera
(subgenus
Mesoponera
), while
Forel (1917)
raised
Hagensia
to subgenus status under
Euponera
.
Arnold (1926)
later raised
Hagensia
to generic status.
Forel (1917)
placed
Xiphopelta
(=
Mesoponera
) under
Euponera
as a distinct subgenus, where it remained on and off until
Brown (1973)
synonymized it with
Pachycondyla
.
Euponera
was treated as a distinct genus until W. L. Brown (in
Bolton
, 1994
) lumped it under
Pachycondyla
without phylogenetic justification.
Euponera
became the
type
genus for
Emery’s (1909
,
1911
)
Euponerinae
, which he considered a section of
Ponerinae
and which basically conformed to the present definition of
Ponerini
.
Emery (1911)
gave a diagnosis for
Euponera
that included
Brachyponera
,
Mesoponera
and
Trachymesopus
(=
Pseudoponera
) as subgenera. He united these taxa based on characters of their mandibles (subtriangular and toothed, with a distinct angle between the masticatory and basal margins), eyes (located in the anterior third of the head), mesosoma (presence of a distinct metanotal groove), and the alate queens. All of these characters are likely plesiomorphic within the
Ponerini
, and do not indicate a close relationship among these genera.
We are reviving
Euponera
as a distinct genus based on both molecular and morphological evidence.
Schmidt's (2013)
molecular phylogeny of the
Ponerinae
and Ward's (pers. comm.) examination of selected African taxa places
Euponera
with strong support within the
Odontomachus
group, but its sister group is unresolved. It is not closely related to
Pachycondyla
or
Pseudoponera
as these are placed in separate genus groups (
Pachycondyla
group and
Ponera
group, respectively). Morphologically,
Euponera
shares basal mandibular pits and a deep metanotal groove with
Brachyponera
, and while these taxa are otherwise morphologically quite different, Schmidt's and Ward's molecular data suggest a close relationship between them. Ward's molecular results suggest a close relationship between
Euponera
and
Fisheropone
, even though they share few morphological characters. Similarly, the distinctive
Cryptopone hartwigi
was also found to be closely related to
Euponera
(and
Fisheropone
). The highly divergent morphologies among these three close relatives belie their true relationships, and have contributed to the fluidity of generic concepts within the subfamily.
Morphologically, some
Euponera
species
are superficially closest to certain members of
Bothroponera
, particularly
Bothroponera comorensis
, while other species are separable from selected
Pseudoponera
species
only by careful examination. However, molecular evidence suggests these similarities are due to convergence as they are not closely related.