Pogonomyrmex inermis Forel 1914
Pogonomyrmex inermis Forel, 1914: 267 (worker). Syntypes examined: 8
workers [MHNG], 2 workers [MACN], 1 worker [MLPA], #204, ARGENTINA, San Luis:
Alto Pencoso (C. Bruch leg.). See also Gallardo, 1932: 128, fig. 18; Kusnezov, 1951: figs.
9a, 9b (MACN worker here designated LECTOTYPE).
Worker
Diagnosis. Within the P. inermis-group,
the character: superior propodeal spines absent or consisting
of small denticles or tubercles uniquely characterizes
this species.
Measurements
- lectotype (n
= 12). HL 1.74 (1.59-1.79); HW 1.86 (1.59-1.84); MOD 0.33 (0.30-0.39);
OMD 0.37 (0.38-0.50); SL 1.26 (1.16-1.35); PNW 1.21 (1.04-1.19);
HFL 1.78 (1.59-1.87); ML 1.85 (1.91-2.18); PW 0.50 (0.39-0.47); PPW 0.61 (0.53-0.63). Indices: SI 67.74 (66.67-76.10); CI 106.90 (98.18-106.98);
OI 17.74 (17.34-22.16); HFI 95.70 (92.13-103.77).
Description. Head
quadrate to slightly wider than long (CI = 98.18– 106.98), widest just
posterior to eyes; posterior margin flat to weakly concave in full-face
view. Longitudinal
cephalic rugae prominent, wavy to irregular, often
moderately rugoreticulate toward posterior margin, in
full face view median rugae diverging slightly toward
posterior corners of head. In side view, rugae posterior to eyes
converging near vertex; vertex rugose. Cephalic interrugal
spaces strongly granulate, dull. Anterior margin of clypeus concave; dorsal surface with several subparallel longitudinal rugae. Mandible with six teeth; mandibular dorsum coarsely striate. MOD ranging from 0.18–0.23x
HL. Eyes in profile situated
slightly anterior to middle of head, OMD = 1.10-1.54x MOD. In full-face view, eyes protruding slightly
beyond lateral margins of head. Antennal
scapes moderately long (SI = 66.67-76.10), failing to
reach vertex by length of basal funicular segment; entire scape
with longitudinal striae. Psammophore well-developed.
Mesosomal profile
strongly convex; all mesosomal surfaces with
prominent irregular rugae to rugoreticulate. Anterior margin of pronotal dorsum with irregular transverse rugae that traverse posteroventrally
or become rugoreticulate on pronotal
sides; dorsum of mesonotum with irregular
longitudinal rugae, rugoreticulate
or vermiculate, rugae on mesopleura
longitudinal or traversing posterodorsally; dorsum of
propodeum with irregular transverse rugae that traverse ventrally or anteroventrally
on propodeal sides. Interrugal spaces
on mesosoma weakly to strongly granulate, dull to weakly
shining. Superior propodeal
spines absent or consisting of very small denticles
or tubercles. Inferior
propodeal spines lacking. Propodeal spiracles narrowly ovate. Legs moderately to strongly coriarious, weakly shining.
Petiolar penduncle about 0.8x as long as
petiole, anteroventral margin often with poorly
developed, broadly rounded process. In
side view, petiolar node asymmetrical with anterior
surface shorter than posterior surface; apex of node broadly rounded. In dorsal view, petiole longer than wide,
widest near spatulate anterior margin. Sides and posterior face of petiole with
coarse, irregular, transverse rugae or rugoreticulate; interrugal spaces
weakly to moderately granulate, weakly shining to shining. Dorsum of postpetiole
convex in profile; in dorsal view, widest near posterior margin, narrowing to anterior margin, maximal width
about equal to length, moderately to strongly coriarious,
dull to weakly shining. Gaster moderately
to strongly coriarious, weakly shining.
Erect
whitish to yellowish pilosity moderately abundant on
head, variable in length, longest hairs not exceeding MOD. Moderately abundant suberect to semidecumbent pilosity on scape; abundant
decumbent hairs on funicular segments.
Legs with moderately abundant suberect
to decumbent white setae. Mesosoma,
petiole, postpetiole, first gastral
tergum with moderately dense erect white setae, often
similar in length, longest hairs on mesosoma approaching
MOD. Body tannish-brown to reddish-brown, posterior portion of
petiole and postpetiole often darker brown, gaster dark brown to blackish.
Queen
Diagnosis. As in
worker diagnosis, but with caste-specific morphology of the mesosoma
related to wing-bearing, presence of small ocelli on
the head, and as illustrated in Fig. x. This
caste is diagnosed by: (1) inferior propodeal spines
lacking, (2) in dorsal view, dorsum of postpetiole
lacking transverse rugae, or rugae
few and incomplete, and (3) body usually bicolored,
with gaster noticeably darker than rest of body.
Measurements
- (n = 12). HL 1.74-2.02; HW
1.79-2.19; MOD 0.39-0.47; OMD 0.39-0.56; SL 1.23-1.39;
Description. As in
worker diagnosis, but with caste-specific morphology of the mesosoma
related to wing-bearing, presence of small ocelli on
head, and as illustrated in Figure x. In
full face view, head quadrate to wider than long (CI = 101.60-108.42), widest
just posterior to eyes, posterior margin flat.
Longitudinal cephalic rugae prominent, wavy to
irregular; in full-face view median rugae not diverging
toward posterior corners of head, interrugal spaces
weakly to moderately granulate-punctate, weakly shining;
vertex rugose, interrugal
spaces moderately granulate-punctate, dull to weakly shining. Mandible with six teeth,
dorsal surface coarsely rugose. Psammophore well-developed.
All mesosomal surfaces with subparallel,
regular, wavy, or irregular rugae; interrugal spaces weakly to moderately granulate-punctate, weakly shining; propodeum
unarmed or with very short denticles; inferior propodeal spines absent.
Petiolar peduncle about as long as petiole, anteroventral
margin straight or with weak process.
In side view, petiolar node asymmetrical with anterior
surface notably shorter than posterior surface, apex of node rounded to weakly angulate. Posterior
surface of petiole with irregular transverse rugae;
dorsum of postpetiole with very weak transverse or
oblique rugae and/or mostly granulate-punctate; interrugal spaces on posterior
surface of petiole and dorsum of postpetiole weakly
to moderately granulate-punctate, weakly shining. Gastral terga weakly to moderately coriarious, weakly shining. Most body surfaces with moderately abundant suberect to erect, medium-length, white to yellowish setae;
moderately abundant suberect to erect hairs on first tergum, those on second and third terga
restricted to dense band along posterior margin. Head, mesosoma,
petiole, postpetiole tannish-brown;
gaster blackish-brown.
Male
Diagnosis. This caste
is diagnosed by: (1) first gastral tergum lacking striae, (2) in
full face view, external margin of apical tooth curved inward, (3) dorsum of postpetiole strongly granulate, dull, to occasionally very
weakly rugoreticulate-vermiculate, interrugae dull, (4) rugae on
head prominent, subparallel, (5) pronotal
sides and mesopleura with longitudinal rugae, and (6) interrugae on
head, pronotal sides, mesopleura
weakly shining to shining.
Measurements
- (n = 12). HL 1.42-1.73; HW
1.43-1.70; MOD 0.46-0.59; OMD 0.20-0.31; SL 0.36-0.49; HFL 1.63-1.90; ML
2.30-2.78; PW 0.46-0.63; PPW 0.62-0.83. Indices:
SI 24.16-31.33; CI 92.55-102.11; OI 30.87-38.00; HFI 109.40-127.70.
Description. Mandibles with three to four teeth on suboblique cutting margin; mandibular
dorsum weakly to moderately rugose medially,
moderately to strongly coriarious laterally; in full
face view, external margin of apical tooth curved inward. Anterior margin of clypeus broadly and
shallowly concave, dorsum with weak longitudinal striae,
interrugae strongly granulate, dull to weakly shining. Antennal scapes
with weak longitudinal striae, strongly granulate, dull to weakly shining. Cephalic rugae prominent, longitudinal to oblique, slightly wavy to
irregular, interrugae weakly punctate,
weakly shining.
In profile,
anterior face of mesonotum meeting pronotal collar at about 45o; juncture between propodeum and propodeal declivity
subangulate, superior propodeal
spines consisting of a longitudinal crest.
Sides of pronotal collar
with irregular longitudinal rugae; mesopleura with weak, wavy to irregular longitudinal rugae, weakly shining to shining. Mesoscutum and mesoscutellum with irregular
longitudinal rugae, notauli
strongly impressed. In dorsal
view, dorsum of propodeum weakly concave with
longitudinal to oblique rugae traversing posteroventrally on sides.
Ventral margin of peduncle with well-developed, elongate, semi-transparent
process that is often wrinkled laterally, strongly granulate, dull. In side view, petiolar node weakly rounded, anterior surface shorter than
posterior surface; posterior surface and sides coarsely rugoreticulate-vermiculate,
weakly shining. Postpetiole wider than long, dorsum and sides strongly
granulate, occasionally weakly rugoreticulate-vermiculate,
dull. Head, mesosoma, petiole, postpetiole
with moderately abundant, sometimes flexuous yellowish hairs, longest about
0.5x MOD; hairs on dorsum of gaster short, restricted
to posterior margins of terga. Gastral terga weakly to moderately coriarious, weakly shining. Head, mesosoma
black; mandibles, antennae, legs, peduncle, gaster
dark ferruginous orange to brownish-orange (Figure x).
Additional material examined.
Etymology.
The specific epithet, inermis (from Latin, inermis = unarmed), refers to this species lacking propodeal spines.
Discussion. Pogonomyrmex inermis is known
to co-occur with P. uruguayensis. Pogonomyrmex inermis can be distinguished from P. uruguayensis by the absence of superior
propodeal spines (reduced to denticles
or small tubercles), whereas P. uruguayensis has distinct superior propodeal
spines. Absence of superior propodeal spines distinguishes P. inermis from all congeners in
Argentina.
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