Pogonomyrmex apterogenos Johnson NEW SPECIES
Holotype worker: ARGENTINA, Catamarca: Departamento
de Tinogasta, Chuschuil
Valley at 20.9 km S Cortaderas, 27º44.0’S 68º08.2’W,
10,380’ (3145 m), 31 January 2010 (R.A. Johnson #4376) [MACN]. Paratypes, same
data as holotype: FML (6w), MACN (24w), LACM (6w),
MCZ (9w), RAJC (21w), UCDC (3w), USNM (3w). Additional paratype
series from the same locality and date - RAJ #4377: MACN (6w), RAJC (6w); RAJ
#4378: MACN (12w), RAJC (11w, 1 ergatoid male): RAJ
#4379: FML (6w), MACN (9w), RAJC (12w); RAJ #4380: FML (3w), MACN (9w), RAJC
(11w, 1 ergatoid male).
Worker
Diagnosis. The combination of: (1) striae
present on first gastral tergum,
(2) longitudinal rugae on promesonotum
very regular, subparallel/ parallel, (3) anterior
margin of pronotum usually with one to several
transverse rugae that continue onto pronotal sides, and (4) longitudinal rugae
adjacent to mid-line of cephalic dorsum converging medially and ending near
posterior margin of clypeus uniquely characterize this species.
Measurements
– holotype (n
= 13 paratypes). HL 1.64
(1.53-1.82); HW 1.68 (1.43-1.79); MOD 0.39 (0.34-0.41); OMD 0.39 (0.34-0.44);
SL 1.33 (1.07-1.36); PNW 1.09 (0.94-1.16); HFL 1.75 (1.35-1.83); ML 1.93
(1.61-2.02); PW 0.41 (0.35-0.44); PPW 0.56 (0.48-0.60). Indices. SI 79.17 (68.94-83.22); CI 102.44
(93.46-102.53); OI 23.21 (21.43-25.00); HFI 104.17 (88.27-104.27).
Description. Head quadrate to slightly longer than wide
(CI = 93.46-102.53); posterior margin flat in full-face view. Longitudinal cephalic rugae
prominent, rugae adjacent to mid-line converge medially
and end near posterior margin of clypeus; interrugal
spaces moderately to strongly granulate-punctate,
dull to weakly shining. Vertex rugose; interrugal spaces weakly
granulate, weakly shining to smoothy and shining. Anterior margin of clypeus moderately
concave, dorsum with numerous suparallel longitudinal
rugae.
Mandible with six teeth; mandibular dorsum
coarsely striated. MOD
ranging from 0.21-0.25x HL. Eyes
in profile situated slightly anterior to middle of head, OMD = 0.92–1.15x
MOD. In full-face view, eyes protruding
slightly beyond lateral margins of head.
Antennal scapes (SI = 68.94-83.22) failing to
reaching posterior corners of head by less than to about the length of the basal
funicular segment. Antennal scapes usually weakly striate, interrstriae
weakly to moderately punctate, weakly shining to smooth
and shining; basal flange well developed with carinate
margin. Psammophore
well developed.
Mesosomal profile flat
to weakly convex; all mesosomal surfaces with
prominent widely spaced, regular, subparallel/parallel
rugae.
In dorsal view, pronotal humeri
enlarged, strongly angulate, especially in lateral
view. Promesonotal
suture usually present; posteromedial portion of pronotum moderately depressed below surrounding surfaces. Rugae on mesonotum longitudinal, on pronotum
diverging to humeri and continuing on pronotal sides; up to several transverse rugae on anterior margin of pronotum
that continue on pronotal sides. Regular to weakly irregular rugae on mesopleura angle posterodorsally; regular transverse rugae
on dorsum of propodeum traverse anteroventrally
on sides. Superior propodeal
spines consist of acuminate denticles, small triangular
teeth, or rarely short spines, length rarely more than width at base, spines usually
connected by well defined keel. Inferior
propodeal spines moderately well developed, wider
than high, triangular, narrowing to broadly rounded to acute tip, height
similar to or slightly greater than length of superior spines. Propodeal spiracles narrowly ovate, facing posterad. Interrugal spaces
on mesosoma moderately to densely granulate, dull to
weakly shining. Legs moderately
coriarious, weakly shining to smooth and shining.
Petiolar peduncle
about as long as petiole, anteroventral margin with a
weak to well developed broadly rounded process. In side view, posterior
surface of petiole weakly convex; petiolar node
asymmetrical with anterior surface notably longer than posterior surface, apex subangulate to angulate. In dorsal view, petiole longer than wide, sides subparallel anterad, slightly narrower posterad,
apex broadly rounded. Sides
and posterior surface of petiolar node with regular transverse
rugae.
Dorsum of postpetiole convex in side view; in
dorsal view, widest near posterior margin, narrowing to anterior margin, width
and length similar; transverse to weakly arcing rugae
posterad, anterad rugae traversing medially from lateral margin then curving anteriorly to become longitudinal; anterolateral
rugae concentric, curving from lateral to anterior margin,
rarely with all rugae transverse or weakly arcing to
anterior. Density and coarseness of rugae on posterior face of petiole and dorsum of postpetiole similar, interrugal
spaces weakly granulate, weakly shining to smooth and strongly shining. Dorsum of first gastral tegum with longitudinal striae, weakly shining.
Erect,
mostly short to medium length, yellowish pilosity
moderately abundant on head, no hairs exceed about 0.7x MOD. Moderately abundant suberect to semidecumbent pilosity on scape; abundant
decumbent hairs on funicular segments.
Legs with moderately abundant suberect
to decumbent yellowish setae. Rest of body with moderately dense, erect, medium-length, yellowish
setae. Head dark ferruginous
orange to dark red-orange; mandibles, antennae, clypeus, frontal lobes, anterior
margin of head black; mesosoma dark orangish-black or blackish to black with orangish-black promesonotum; gastral terga very dark
orange-black.
Queen
Diagnosis. This caste is diagnosed by: (1) ergatoid, (2) first gastral tergum striate, silky in appearance, (3) anterior margin of
clypeus entire, and (4) in dorsal view, pronotum and mesoscutum poorly differentiated with longitudinal rugae on mesoscutum that continue
longitudinally or obliquely onto pronotum.
Measurements
- (n = 6). HL 1.83-1.96; HW
1.84-1.94; MOD 0.43-0.48; OMD 0.43-0.51; SL 1.25-1.42;
Description. Ergatoid; in full
face view, head quadrate to subquadrate (CI = 95.92-103.28),
posterior margin flat. Cephalic dorsum
with wavy, longitudinal rugae, medial rugae not diverging toward vertex along posterior margin,
medial rugae usually converging near posterior margin
of clypeus; vertex rugose, interrugal
spaces on cephalic dorsum and vertex moderately granulate-punctate,
dull to weakly shining. Mandibles with
six teeth, dorsal surface coarsely rugose. Psammophore well
developed.
Mesosoma lacking
all morphological structures related to or for insertion of wings; all mesosomal surfaces with subparallel,
wavy rugae; interrugal
spaces smooth and shining to moderately granulate-punctate,
weakly shining. Pronotum
large with longitudinal or oblique rugae that continue
from mesoscutum and traverse ventrally on pronotal sides, anterior margin occasionally with
transverse rugae.
Mesoscutum reduced in size, not extending to pronotal collar; sides subparallel,
converging to bluntly acuminate arch-shaped anterior margin. Dorsum of propodeum transversely rugose;
superior spines reduced to small teeth; inferior spines well developed, larger
than superior spines, triangular with acuminate tip. Petiolar peduncle
long, anteroventral margin with weakly developed
rounded process. In side view, petiolar node asymmetrical with anterior
surface notably shorter than posterior surface, apex of node angulate. Postpetiole
convex in profile; in dorsal view, maximum width about equal to length. Posterior face of petiole and dorsum of postpetiole with wavy transverse rugae;
interrugal spaces weakly punctate,
wealkly shining to shining. First gastral
tergum with fine, longitudinal striae,
weakly shining. Most body
surfaces with moderately abundant suberect to erect,
short, white to cream-colored setae, longest hairs on posterior terga. Head
ferruginous orange; pronotum, mesoscutum,
first gastral tergum
blackish ferruginous orange; antennae, clypeus, frontal lobes, mandibles, and
rest of body blackish to black, sometimes with slight orangish
infusion.
Male
Diagnosis. This caste is diagnosed by: (1) ergatoid, (2) in side view, cephalic rugae
extending more or less directly to vertex, not forming circumocular
whorls and not converging posterior to eyes, and (3) notauli
absent.
Measurements
- (n = 8 + 2 paratypes).
HL 1.35-1.60; HW 1.35-1.64; MOD 0.42-0.48; OMD 0.21-0.31; SL 0.54-0.61; HFL
1.52-1.70; ML 1.84-2.20; PW 0.42-0.49; PPW 0.57-0.66. Indices. SI 34.76-42.22; CI 92.47-106.34; OI
29.14-33.10; HFI 103.40-118.52.
Description. Ergatoid, mesosoma lacking morphological structures related to or for
insertion of wings. Mandible
with four to five teeth on suboblique cutting margin;
mandibular dorsum coarsely rugose
laterally, weakly rugose medially. Anterior margin of clypeus concave,
dorsum rugose in various orientations. Antennal scapes reaching to or near posterior margin of eye, mostly
smooth and shining. Longitudinal rugae on cephalic dorsum prominent, wavy; in side view, rugae extending directly to vertex, interrugae
moderately granulate, weakly shining.
All mesosomal surfaces with subparallel
rugae, interrugae weakly to
moderately granulate, weakly shining. In
dorsal view, pronotum enlarged and well-defined, mesoscutum reduced in size, arch-shaped, not reaching pronotal collar; notauli absent. In side view, juncture of dorsum of propodeum and propodeal declivity
angulate, superior propodeal
spines reduced to acuminate teeth, inferior propodeal
spines well developed, wider than long, apex broadly rounded. Anteroventral
margin of petiolar peduncle with small to medium
sized rounded process. In side view, anterior
face of petiole shorter than posterior face; node subangulate
to rounded. Posterior
face of petiole and dorsum of postpetiole transversely
rugose, interrugae smooth
and shiny to moderately coriarious, weakly shining. Entire body with moderately abundant short to
long flexuous white to yellowish hairs, longest on head similar in length to
MOD; scattered hairs present over first gastral tergum. Gaster enlarged, first gastral tergum finely striate, weakly shining. Head, mesoscutum, mesoscutellum ferruginous orange to dark ferruginous
orange; postpetiole blackish orange; gaster dark ferruginous orange to black; antennae, frontal
lobes, mandibles blackish orange; rest of body black (Figure x).
Additional
material. ARGENTINA:
Catamarca: Rt 45 at 28.4 km S Cortaderas,
10,170’, Jan. 28, 2010 (RAJC); Rt 45 at 13.7 km S Cortaderas, 10,900’,
Jan. 5, 2006 (RAJC); Rt 45 at 1.4 km N Cortaderas, 11,070’, Jan. 9, 2010 (RAJC); Rt 45 at 20.5 km N Cortaderas,
11,090’, Jan. 5, 2010 (CASC; RAJC); Rt 45 at 30.5 km
E Chile border, 13,330’, Jan. 30, 2010 (RAJC).
Etymology. The specific epithet, apterogenos (Latin, aptero = wingless and genos = parentage), refers to this species having ergatoid or wingless queens and males.
Discussion. Pogonomyrmex apterogenos is not known to co-occur with any congeners,
but it is similar to several high-elevation congeners in which the first gastral tergum is striate and longitudinal
rugae on the promesonotum
are very regular, subparallel/parallel; these similar
species include P. lagunabravensis,
P. longibarbis, and P. pulchellus. Pogonomyrmex apterogenos can be distinguished from all three of
these species based on their medial cephalic rugae,
which converge and end near the posterior margin of the clypeus. In P. lagunabravensis,
P. longibarbis, and P. pulchellus, the medial cephalic rugae are subparallel/parallel
and typically continue onto the clypeus rather than ending near the posterior
margin of the clypeus.