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
Psalidomyrmex
André
Fig. 40
Psalidomyrmex
André
, 1890: 313
(as genus). Type-species:
Psalidomyrmex foveolatus
André
, 1890: 314
; by monotypy.
Psalidomyrmex
is a small genus (six described species) restricted to central and western Africa. They are cryptic foragers, and at least one species is a specialist predator of earthworms.
Diagnosis.
Psalidomyrmex
workers and queens are readily identified by their unique mandibular structure (mandibles falcate to subtriangular, with broadly rounded basal angles and an attenuated apical tooth) and by their projecting labral lobe, both of which are autapomorphic within the
Ponerinae
. Other diagnostic characters include the hypertrophied frontal lobes, longitudinal groove on the propodeal dorsum, and large lateral metapleural gland orifice.
Psalidomyrmex
is most similar to the other members of the
Plectroctena
genus group, including
Loboponera
and
Plectroctena
itself. In addition to lacking the two autapomorphies of
Psalidomyrmex
already mentioned, these genera differ from
Psalidomyrmex
in having longitudinal dorsal grooves in the meso- and metafemora and distinct propodeal lamellae.
Synoptic description.
Worker.
Medium to large (TL 9.0–16.0 mm;
Bolton
, 1975b
) ants with the standard characters of
Ponerini
. Mandibles falcate to subtriangular, with rounded basal angles, a long apical tooth and a basal groove. Labrum projecting anteriorly beyond the anterior clypeal margin as a lobe. Frontal lobes large, expanded laterally and closely approximated. Eyes of moderate size, located anterior to head midline. Metanotal groove vestigial. Propodeum broad dorsally, with a shallow longitudinal groove dorsally. Propodeal spiracles round. Metapleural gland orifice very large, opening laterally. Metatibial spur formula (1p). Petiole nodiform. Anteroventral articulatory surface of petiole long and broad, with a narrow median V-shaped longitudinal groove. Gaster with a strong constriction between A3 and A4. Head and body with moderate sculpturing (variously punctate, foveolate or striate), with very sparse pilosity and no pubescence. Color reddish brown to black.
FIGURE 40.
Worker caste of
Psalidomyrmex procerus
: lateral and dorsal view of body and full-face view of head (CASENT0003082, April Nobile and www.antweb.org); world distribution of
Psalidomyrmex
.
Queen.
Similar to workers but slightly larger, alate and with ocelli.
Male.
See
description in
Bolton
(1975b)
.
Larva.
Described for
P. procerus
by
Wheeler & Wheeler (1964)
.
Geographic distribution.
Psalidomyrmex
is restricted to central and western Africa, ranging from
Sierra Leone
to
Kenya
and as far south as
Gabon
and the
Democratic Republic of Congo
(
Bolton, 1975b
;
Bolton & Brown, 2002
).
Ecology and behavior.
Very little is known about the ecology and behavior of
Psalidomyrmex
. They nest in rotting logs, in the soil beneath rotting logs (
Bolton
, 1975b
), or in deserted termitaries (Déjean
et al.
, 1996, 1997), and workers forage individually in rotting wood or in leaf litter (
Bolton
, 1975b
).
P. procerus
is known to be a specialist predator of earthworms (
Lévieux, 1982
;
Déjean
et al.
, 1992
), and though the feeding habits of the other species is unknown, it seems likely that they too may feed on earthworms, given the apparently specialized mandibular structure of the genus.
Phylogenetic and taxonomic considerations.
Psalidomyrmex
was erected by
André
(1890)
to house the single species
P. foveolatus
.
Bolton
(1975b)
revised the genus, and
Bolton
& Brown (2002)
gave an updated diagnosis.
André
(1890)
apparently believed that
Psalidomyrmex
was closely related to
Belonopelta
, due to supposed similarities in their mandibular structure. However, P.S. Ward (pers. comm.) found that
Belonopelta
belongs to the
Pachycondyla
group while
Schmidt (2013)
placed
Psalidomyrmex
in the
Plectroctena
group. The only real similarity in the mandibles of these genera is the attenuated apical tooth, which occurs in at least two other ponerine genera (
Emeryopone
and
Thaumatomyrmex
) and this similarity is clearly convergent.
Psalidomyrmex
has been grouped with
Plectroctena
since
Emery (1911)
included it in his subtribe
Plectroctenini
, though this was based on weak evidence.
Bolton
(1974)
argued for a close relationship between these genera based on the structure of the mesosoma, petiole and gaster, a similar reduction in palpal segments, and male morphological characteristics.
Bolton
& Brown (2002)
found additional evidence for a close relationship between
Psalidomyrmex
and
Plectroctena
in the structure of the anterior petiolar articulatory surface (see also
Fisher, 2006
).
Schmidt's (2013)
molecular phylogeny of the
Ponerinae
confirms this close relationship, with
Psalidomyrmex
resolved as sister to
Loboponera
+
Plectroctena
.
Boloponera
is also probably in this sister clade.