Pogonomyrmex tinogasta Johnson
NEW SPECIES
Holotype worker: ARGENTINA, Catamarca: Departamento
Tinogasta, Ruta 11 at 17.5
km south of Tinogasta, 28o12.8’S 67o37.2’W,
4390 feet (1330 m), 4 January 2006 (R.A. Johnson #3753) [MACN]. Paratypes, same
data as holotype: CASC (1w), FML (3w), MACN (9w),
LACM (3w), MCZ (3w), RAJC (9w), USNM (3w). Additional paratype
series from the same locality and date - RAJ #3754: FML (3w), MACN (9w), RAJC
(9w), UCDC (3w); RAJ #3755: MACN (9w), RAJC (9w).
Worker
Diagnosis. Within the P.
laticeps-group, the combination of: (1) body concolorous black except for
dark reddish band encircling eye, (2) rugae on promesonotum longitudinal, usually regular, and (3) medial rugae along posterior margin of head longitudinal, rarely rugoreticulate uniquely characterize this species.
Measurements
- holotype (n
= 12 paratypes). HL 2.02
(1.74-2.02); HW 2.08 (1.79-2.23); MOD 0.45 (0.36-0.45); OMD 0.58 (0.45-0.57);
SL 1.51 (1.33-1.57);
Description. Head slightly to
moderately wider than long (CI = 102.87-113.78), widest just posterior to eye;
posterior margin flat in full-face view.
Longitudinal cephalic rugae prominent,
slightly wavy to irregular, in full-face view median rugae
diverging weakly toward posterior corners of head. In side view, rugae posterior to eyes converging toward vertex; vertex rugose. Cephalic interrugal spaces weakly to moderately
granulate-punctate, weakly shining to shining. Anterior margin of clypeus
flat to weakly concave; dorsal surface with numerous subparallel
longitudinal rugae. Mandible with six teeth; mandibular
dorsum coarsely striated. Numerous long,
curved, bristle-like, yellowish to brownish hairs project from anterior margin
of clypeus and basolateral margin of mandibles. MOD ranging from 0.19-0.24x
HL. Eyes in profile situated near
middle of head, OMD = 1.09-1.39x MOD.
Antennal scapes relatively long (SI = 62.44-76.54),
failing to reach vertex by up to length of basal funicular segment; smooth and
shining, distal portion often weakly striate.
Basal flange of scape flattened and well developed
with carinate margin.
Psammophore well developed.
Mesosomal profile
flat to weakly convex; all mesosomal surfaces with
prominent rugae.
In side and dorsal views, humeral shoulders angulate, occasionally weakly elevated above medial portion
of pronotum.
Dorsum of promesonotum with wavy to irregular longitudinal
rugae that diverge anteriorly
toward humeral angles, occasionally weakly rugoreticulate
or irregularly transverse; anterior margin of pronotum
with wavy to irregular transverse rugae that traverse
ventrally on pronotal sides. Mesopleura with wavy to irregular rugae angling posterodorsally, rugae often more
irregular to rugoreticulate near anterodorsal
margin. Posterior
face of propodeum with transverse to weakly irregular
rugae that traverse anteroventrally
on sides. Propodeum with long, acuminate
spines connected by well defined keel; spines longer than distance between bases. Inferior propodeal spines absent or reduced to indistinct broadly
rounded process. Propodeal
spiracles narrowly ovate. Interrugal
spaces on mesosoma weakly to moderately punctate to coriarious, weakly shining. Legs moderately coriarious, weakly shining.
Petiolar peduncle
only slightly shorter than petiole, anteroventral
margin with bluntly angulate tooth-like process. In side view, petiolar
node broadly but asymmetrically rounded, with anterior surface shorter than
posterior surface. Apex
of node weakly angulate to rounded. In dorsal view, petiolar
node longer than wide, sides subparallel to slightly wider
near spatulate anterior margin; dorsum and sides with
moderately strong wavy to irregular, transverse to arc-shaped rugae. Dorsum of postpetiole convex in profile; in dorsal view, widest near
posterior margin, narrowing toward anterior margin; maximal width about equal
to length; dorsum and sides with wavy to irregular transverse rugae that are weaker, more closely spaced than on
petiole. Interrugal spaces weakly coriarious, weakly shining on petiole, weakly to moderately
coriarious, dull to weakly shining on postpetiole. Dorsum of gaster weakly to moderately coriarious, weakly shining to shining.
Erect
whitish 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 semidecumbent
white setae. Mesosoma, petiole, postpetiole, gastral terga with moderately dense, erect setae, mostly similar in
length, only those on posterior gastral terga approaching MOD. Entire body concolorous black, often with slight dark reddish to
brownish hue; circumference of eyes often dark reddish-black.
Queen (dealate)
Diagnosis. This caste
is diagnosed by: (1) pronotum meeting the mesoscutum
at a shallow angle (approximately 45o), (2) posterior margin of pronotum with transverse rugae,
and (3) body concolorous black.
Measurements
- (n = 12). HL 2.19-2.38; HW
2.44-2.64; MOD 0.47-.59; OMD 0.57-0.61; SL 1.55-1.73;
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 wider than long (CI = 105.96-117.65), posterior margin weakly
concave medially. Longitudinal cephalic rugae prominent, slightly wavy; in full-face view median rugae diverging weakly toward posterior corners of head, interrugal spaces weakly coriarious,
weakly shining to smooth and shining; vertex rugose, interrugal spaces smooth, shining. Mandible with six teeth,
dorsal surface coarsely rugose. Psammophore well-developed.
All mesosomal surfaces with subparallel,
regular to wavy rugae; interrugal
spaces weakly coriarious, weakly shining to smooth
and shining. In profile, pronotum meets mesoscutum at
shallow angle (approximately 45o).
Superior propodeal spines short to medium-long;
inferior spines absent to very weakly developed. Petiolar peduncle
about 0.8x as long as petiole, anteroventral
margin with acute triangular process. In
side view, petiolar node asymmetrical with anterior
surface notably shorter than posterior surface, apex of node weakly angulate to rounded.
Postpetiole wider than long. Posterior
face of petiole with transverse or oblique, regular to irregular rugae; dorsum of postpetiole with
weaker, denser, transverse rugae; interrugal
spaces on petiole and postpetiole weakly coriarious, weakly shining to smooth and shining. Gastral terga weakly coriarious,
shining. Most body surfaces with
moderately abundant suberect to erect, short to
medium-length white setae. Entire body concolorous black, often with
reddish tinge; circumference of eyes a lighter reddish-black.
Male: Unknown.
Additional
material examined. ARGENTINA: Catamarca: Rt 11 at 4.8 km S Tinogasta,
3990’, Jan. 17, 2010 (RAJC); Rt 60 at 20.5 km W Cordobita, 3630’, Jan. 5, 2006 (RAJC); Rt
60 at 24.8 km NW Cordobita, 3670’, Jan. 5, 2006
(RAJC).
Etymology. The specific epithet, tinogasta, is a noun in apposition and invariant in form that is derived
from a small localized group of Indians that lived in a pueblo of the same
name.
Discussion. Pogonomyrmex tinogasta is not
known to co-occur with P. mendozanus or
P. tinogasta.
Pogonomyrmex tinogasta can
be distinguished from P. mendozanus by the coarse, irregular rugae
on head and mesosoma, whereas rugae
on the head and mesosoma of P. mendozanus are fine and very
regular. Pogonomyrmex tinogasta can be distinguished from P. laticeps
based on the following characters: (1) body concolorous
black except for dark reddish band encircling eye, (2) promesonotal
rugae longitudinal, usually regular, and (3) medial rugae along posterior margin of head longitudinal, rarely rugoreticulate. In P. laticeps,
the head and mesosoma are dark reddish-black, gaster black, rugae on promesonotum transverse, oblique, or irregular, rarely
longitudinal, and medial rugae along posterior margin
of head usually partly rugoreticulate.