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
Emeryopone
Forel
Fig. 45
Emeryopone
Forel, 1912: 761
(as genus). Type-species:
Emeryopone buttelreepeni
Forel, 1912: 762
; by monotypy.
Emeryopone
is a small genus (five described species) which ranges from
Israel
to
Indonesia
. Almost nothing is known about its habits, but its unusual mandibles suggest a specialized diet.
Diagnosis.
Emeryopone
workers are easily separated from most other ponerines by their long curved mandibles, which have five long teeth, the apical tooth greatly attenuated. The only genus with similar mandibles is
Belonopelta
, and to a much lesser extent
Thaumatomyrmex
.
Emeryopone
and
Belonopelta
can be separated by their frontal lobes (which are medium sized and separated anteriorly by a posterior extension of the clypeus in
Emeryopone
,
and very small and closely approximated in
Belonopelta
) and body sculpturing and pilosity (foveolate with abundant short pilosity and variable pubescence in
Emeryopone
, and pruinose without upright pilosity in
Belonopelta
).
Thaumatomyrmex
has much longer mandibular teeth than
Emeryopone
,
much more widely spaced frontal lobes, and larger eyes, among other differences.
Synoptic description.
Worker.
Small (TL
3.2–4.9 mm
) ants with the standard characters of
Ponerini
. Mandibles long, narrow, with five teeth, the apical tooth greatly attenuated. Mandibles without a basal groove. Anterior clypeal margin convexly triangular. Frontal lobes small to moderate in size. Eyes small to very small, located far anterior of head midline. Metanotal groove absent or a vestigial suture. Propodeum broad dorsally. Propodeal spiracles round. Metatibial spur formula (1p). Petiole nodiform, the node rounded and wider than long. Subpetiolar process usually with a small lateral fovea near the anterior end. Gaster with a moderate girdling constriction between pre- and postsclerites of A4. Tergite of A4 moderately arched, the gaster mildly recurved. Head and body foveolate, with very light striations on the sides of the mesosoma and with abundant short pilosity and abundant to absent pubescence. Color ferruginous to black.
Queen.
Described only for
E. melaina
: Similar
to worker but slightly larger and alate, with three ocelli, larger eyes, and the modifications of the thoracic sclerites typical for winged ponerine queens (
Xu, 1998
).
Male.
Not
described.
Larva.
Not
described.
Geographic distribution.
Emeryopone
has an unusual distribution, with collections known from
Israel
,
India
,
Nepal
, southern
China
,
Indonesia
, and
Malaysia
(
Baroni Urbani, 1975
;
Xu, 1998
;
Varghese, 2006
; pers. obs.). Collections are rare and probably underestimate the true range of
Emeryopone
(
Baroni Urbani, 1975
)
.
Ecology and behavior.
Basically nothing definite is known about the habits of
Emeryopone
. Based on their morphological characteristics and on collection data they are almost certainly cryptobiotic, and the rarity with which they are collected (
Baroni Urbani, 1975
;
Xu, 1998
;
Varghese, 2006
) suggests a low population density, though this may be an artifact of inadequate collection methods, as apparently has been the case with
Thaumatomyrmex
(see under that genus). The extremely similar mandibular structure of
Emeryopone
and
Belonopelta
suggests a similar diet preference, and though the feeding habits of
Emeryopone
have not been reported, some
Belonopelta
feed to a large degree on diplurans.
Emeryopone
may have a similar diet specialization. The downcurved gaster of
Emeryopone
implies that it hunts in tight spaces.
Phylogenetic and taxonomic considerations.
The proper taxonomic status of
Emeryopone
is somewhat uncertain.
Forel (1912)
described
Emeryopone
for the single species
E. buttelreepeni
but noted its similarity with
Belonopelta
, apparently separating it from that genus only by its lack of a medial tooth on the anterior clypeal margin (which is present in
B. attenuata
but not in
B. deletrix
, described later) and implicitly by its obsolete metanotal groove.
Baroni Urbani (1975)
later synonymized
Emeryopone
under
Belonopelta
, noting that those two characters are present in varying degrees in the other species he included in
Belonopelta
.
FIGURE 45.
Worker caste of
Emeryopone buttelreepeni
: lateral and dorsal view of body and full-face view of head (CASENT0104586, April Nobile and www.antweb.org); world distribution of
Emeryopone
.
Baroni Urbani’s (1975)
synonymizing of
Emeryopone
under
Belonopelta
is undermined by his taxonomic treatment of
Belonopelta
: he included both
Simopelta
and
Emeryopone
as junior synonyms of
Belonopelta
, while removing
B. deletrix
to the separate genus
Leiopelta
. Molecular evidence indicates that
Emeryopone
is not even sister to
Simopelta
and there is no morphological evidence to suggest otherwise. Further, P.S. Ward (pers. comm.) has found that
Belonopelta
belongs to the
Pachycondyla
group while
Schmidt (2013)
placed
Emeryopone
in the
Ponera
group. Thus it is seems clear that the morphological similarities between
Belonopelta
and
Emeryopone
are the result of convergence rather than close relationship.
Schmidt's (2013)
molecular phylogeny of the
Ponerinae
places
Emeryopone
within the
Ponera
genus group as sister to the clade composed of
Ponera
,
Ectomomyrmex
,
Cryptopone
,
Austroponera
,
Parvaponera
and
Pseudoponera
. Morphological evidence suggests that
Emeryopone
may actually be sister to
Ponera
, as both genera share an overall similar gestalt and both have a fenestra in the subpetiolar process (absent in one
Emeryopone
species
). They differ most obviously in their mandibles and in the vaulting of A4. A sister relationship between
Emeryopone
and
Ponera
cannot be statistically rejected (
Schmidt, 2013
).