Pogonomyrmex serpens
Santschi 1922 NEW STATUS
Pogonomyrmex cunicularis (sic) var. serpens Santschi, 1922b:
349 (worker). Syntypes examined: 2 workers [MACN], #1073,
BOLIVIA, San José, at two hours on the path to Carumba
(Lizer and Delétang leg.). Kusnezov, 1951: 251 [synonomy
under cunicularius;
not confirmed here]. See also Gallardo, 1932: 123, fig. 15 (MACN worker here
designated LECTOTYPE). NEW STATUS
Pogonomyrmex cunicularis (sic) var. carnivora Santschi, 1925a: 155, fig. 2 (worker). Syntypes
examined: 6 workers [MACN], 1 worker [MZUSP], #1614,
Worker
Diagnosis. Within the P. cunicularius-group,
the combination of: (1) in lateral view, apex of petiolar node weakly rounded to angulate, (2) inferior propodeal spines acuminate,
(3) superior propodeal spines long, length greater
than distance between bases, (4) first gastral tergum moderately coriarious,
weakly shining, (5) sculpturing on dorsum of mesosoma
and posterior surface of petiole coarse, rugoreticulate
to vermiculate, and (6) bicolored, mesosoma, petiole darker than rest of body uniquely
characterize this species.
Measurements - lectotype (n = 12). HL 2.40 (2.00-2.33); HW 2.02 (1.65-2.00); MOD 0.37 (0.32-0.42);
OMD 0.76 (0.46-0.62); SL 1.74 (1.58-1.81);
Description. Head elongate (CI = 81.13-87.50), widest
immediately posterior to mandibles, narrowing posterior to eyes and forming a
broadly rounded vertex; posterior margin flat to weakly convex in full-face
view. Dorsum of head
with moderately strong longitudinal, wavy to irregular rugae
or weakly rugoreticulate; in full-face view median rugae diverging only slightly toward posterior corners of
head. Vertex
weakly to moderately rugose, dull to weakly shining. Cephalic interrugal
spaces weakly to moderately granulate, weakly shining. Anterior margin of clypeus
flat to weakly convex; dorsal surface with more than several subparallel longitudinal or oblique rugae. Mandibles with six teeth; mandibular
dorsum coarsely striated. Eyes small, MOD ranging from 0.15–0.19x HL. Eyes in profile, situated anterior to middle
of head, OMD = 1.27-1.75x MOD; in full-face view, eyes protruding beyond
lateral margins of head. Antennal scapes long (SI = 86.14-97.21), surpassing vertex by less
than length of first funicular segment; entire scape
with longitudinal striae. Basal flange of scape well-developed with carinate
margin. Psammophore
poorly developed, consisting of short to medium-length hairs scattered across
ventral side of head.
Promesonotal profile weakly convex, propodeum flat; all
mesosomal surfaces with irregular rugae
or rugoreticulate-vermiculate. In dorsal view, humeral portion of pronotum rounded. Dorsum of promesonotum and sides of pronotum rugoreticulate to
vermiculate; mesopleura with irregular rugae that angle posterodorsally. Superior propodeal
spines long, narrowing to acuminate tip, length greater than distance between
bases; spines connected by well-defined keel; irregular transverse rugae on propodeal dorsum
traverse ventrally or anteroventrally on sides. Inferior propodeal spines well-developed, triangular, wider than
high, with an angulate to acute tip. Propodeal spiracles narrowly ovate.
Interrugal spaces on mesosoma
smooth to weakly granulate, weakly shining to shining. Legs long (HFL = 2.22-2.79 mm), weakly to
moderately coriarious to granulate, weakly shining.
Petiolar
peduncle about 0.8x as long as petiole, anteroventral margin with acuminate spine. In side view, posterior face of petiole
flattened; petiolar node asymmetrical with anterior
surface shorter than posterior surface, apex of node weakly rounded to angulate, usually slightly elevated above posterior surface. In dorsal view, petiolar
node about 1.5x longer than wide, widest near anterior
margin. Posterior face of petiole with
coarse, irregular rugae to rugoreticulate,
interrugal spaces weakly to moderately punctate, weakly shining.
Dorsum of postpetiole convex in profile; in
dorsal view, widest near posterior margin, narrowing towards anterior margin,
maximum width about equal to length, strongly granulate-punctate
or with weak irregular transverse rugae, dull to weakly
shining. Dorsum of gaster moderately coriarious, weakly
shining.
Erect
to semi-erect yellowish pilosity moderately abundant
on head, variable in length. Moderately abundant suberect yellowish pilosity on scape; abundant
decumbent hairs on funicular segments.
Legs with moderately abundant subdecumbent
to decumbent yellowish setae. Mesosoma, petiole,
postpetiole, and dorsum of gaster
with moderately dense erect setae, mostly similar in length, longest hairs on
posterior gastral terga; longest
hairs on rest of body rarely >0.5x MOD. Bicolored with mesosoma and petiole darker than rest of body, but color varies
geographically. In
Queen
Diagnosis. Ergatoid, with
small ocelli on head; otherwise as in worker
diagnosis, and as illustrated in Figure x.
This caste is diagnosed by: (1) anterior margin of clypeus flat to weakly
convex, apron lacking clypeal teeth, (2) node of petiole angulate
in lateral view, (3) inferior propodeal spines about
as wide as high, acuminate, (4) first gastral tergum moderately coriarious,
dull to weakly shining, (5) sculpturing on dorsum of mesosoma
and posterior face of petiole weak to moderately strong, rugae
irregular to moderately rugoreticulate, and (6) bicolored, mesosoma dark
red-orange; head, legs, petiole, postpetiole, gaster lighter red-orange.
Measurements - (n = 5). HL 1.97-2.41; HW 1.63-2.20; MOD 0.35-0.43; OMD 0.42-0.66;
SL 1.46-1.84;
Description. Ergatoid; mesosomal segments fused, mesoepinotal
suture often slightly impressed, lacking all morphological structures related
to or for inserting wings.
Promesonotum
mostly rugoreticulate to vermiculate; propodeum with irregular transverse rugae
that traverse ventrally on sides.
Propodeum with long superior spines; spine length similar to or slightly
longer than distance between bases; inferior propodeal
spines well-developed, triangular, wider than high, with angulate
to acute tip. Petiolar peduncle about as long as
petiole, anteroventral margin with acute spine-like
process. In side view, petiolar node asymmetrical with anterior
surface notably shorter than posterior surface, apex of node angulate. Posterior face of petiole with irregular transverse rugae to rugoreticulate-vermiculate;
interrugal spaces weakly punctate,
weakly shining to smooth and shining.
Postpetiole convex in profile; in dorsal view,
maximum width about equal to length; dorsum varies from moderately to strongly
granulate-punctate, with weak irregular transverse rugae, or rugoreticulate, dull to
weakly shining. Dorsum of gaster moderately to strongly coriarious,
dull to weakly shining. Most body
surfaces with moderately abundant suberect to erect,
short yellowish setae.
Bicolored: mesosoma
dark red-orange; head, legs, petiole, postpetiole; gaster lighter red-orange.
Male. Unknown.
Additional material examined. ARGENTINA: Chaco: Colonia Benítez, no date (LACM; MHNG). Corrientes:
San Roque, no date (MACN); no loc., Feb. 1920 (MACN; USNM). Formosa:
Reserva El Bagual, 151m, Apr. 2005 (RAJC). Misiones:
no loc., Dec. 1920 (MACN). Santa Fe: Ruta 11 at 23 mi S Villa Ocampo, 140m,
Dec. 20, 2004 (RAJC); 22 km S Reconquista, 45m, Nov.
15, 2003 (RAJC); Ruta 34 at 3 km W Santa Ana, 145m, Dec.
20, 2004 (RAJC); Fives Lille, no date (MACN; MZUSP). BOLIVIA: Santa
Cruz: Los Negros, Oct. 10,
1962 (LACM). PARAGUAY: Boquerón:
Nueva Asunción, 1050’, Nov. 2-6, 2001 (RAJC); Enciso, 830’, Nov. 4-6, 2001 (ALWC;
RAJC); Estancia Maria Vicenta, 780’, Sep. 27-29, 2004
(RAJC); Fortin Mayor Infante Rivarola, 910’, Oct.
1-4, 2004 (RAJC); Garrapatal, 710’, Nov. 5-6, 2001
(RAJC); Mister Long, 460’, Sep. 17-18, 2003 (RAJC);
Laguna Salada de Salazan, Dec.
5, 1993 (ALWC); Ruta Trans-Chaco, 180m, Dec. 4, 2002 (ALWC);
Mariscal Estigarribia, Nov. 22, 1994 (ALWC); 4 km NW Mariscal Estigarribia,
180m, Dec. 12, 2002 (ALWC); 80 km SW Destacamento Teniente
Pico, Aug. 6, 1994 (ALWC); Parque Nacional Teniente
Enciso, Park Administration area,
Aug. 6-7, 1994 (ALWC). President
Hayes: Los Pioneros, 420’, Oct. 9-11, 2003 (RAJC); Rio Verde, 350’,
Oct. 15-16, 2003 (RAJC); Ruta Trans-Chaco, 120m, Dec. 5, 2002 (ALWC). Questionable
locales:
Etymology. The
specific epithet, serpens (from Latin, serpens = serpent), refers to a
snake. Santschi
did not discuss the naming of this species, so its derivation is unclear. The name might refer to the narrow, elongate
body of this species.
Discussion. Pogonomyrmex serpens
is not known to co-occur with any other P.
cunicularius-group species, but it is likely to
co-occur with both P. cunicularius and P. pencosensis. Pogonomyrmex serpens can be distinguished from P. cunicularius by the combination of:
(1) petiolar node angulate
in lateral view, (2) inferior propodeal spines about
as wide as high with an acute tip, (3) first gastral tergum moderately to strongly coriarious,
dull to weakly shining, and (4) superior propodeal
spines long, length greater than distance between bases. In P. cunicularius, the petiolar
node is rounded in lateral view, the inferior propodeal
spines are wider than high with a broadly rounded apex, the first gastral tergum is smooth and polished,
strongly shining, and superior propodeal spines are
short, length less than distance between bases.
Pogonomyrmex serpens can
be distinguished from P. pencosensis by the combination of: (1) sculpturing on
dorsum of mesosoma and posterior face of petiole
coarse, rugoreticulate to vermiculate, and (2) body bicolored with mesosoma and
petiole medium to dark orangish-brown to
reddish-brown, rest of body lighter. In P. pencosensis,
sculpturing on dorsum of mesosoma and petiole is weak
to moderately strong, rugae are irregular to moderately
rugoreticulate, and the body is concolorous
tannish-red.
In describing P. cunicularius var. serpens, Santschi
did not note specific differences from the other two forms, but said only that
the head was a dark reddish-brown, and that sculpturing on the mesosoma consisted of irregular rugae
to vermiculate on both the dorsum and sides.
The bicolored body and the much stronger and
more irregular-vermiculate sculptuing on the mesosoma make this form morphologically distinct from both P. cunicularius
and P. pencosensis. Thus, I raise P. serpens from synonomy to rank as a valid species.
Santschi
described P. cunicularius var. carnivora as very similar to variety serpens, except
that the former was slightly larger and had much longer superior propodeal spines (twice the length as distance between
bases compared to similar to distance between bases in serpens). Examination of numerous series of P. serpens demonstrate that
variation in body size and spine length described by Santschi
occurs within colonies. Thus, I synonomize P. cunicularius var.
carnivora under P. serpens.
In regard
to the type locality, Santschi gave a vague description
saying that it was San José, two hours from Carumba,
which is likely Corumba, Mato
Grosso, Brazil.
The only
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