Pogonomyrmex abdominalis Santschi 1929
Pogonomyrmex (Ephebomyrmex) naegelii st. abdominalis Santschi, 1929:
278 (worker, queen). Syntypes examined: 8 workers,
4 queens [MACN], #1710, ARGENTINA, Córdoba: Sierras de Córdoba, Alta Gracia La
Granja (Charles Bruch leg.). See also Gallardo, 1932:
112, figs. 6, 7 (MACN worker here designated LECTOTYPE).
Pogonomyrmex (Ephebomyrmex) abdominalis Santschi; Kusnezov, 1951: 250. Raised to species.
Ephebomyrmex abdominalis (Santschi);
Kempf, 1972: 106. First combination
in Ephebomyrmex.
Pogonomyrmex abdominalis Santschi; Lattke, 1991: 305. Revived
combination in Pogonomyrmex.
Worker
Diagnosis. Within the P. naegelii-group, the combination of:
(1) approximately
8-10 coarse longitudinal rugae between frontal lobes,
(2) lacking a small lobe that projects dorsally from anterior margin of
antennal fossa, (3) peduncle and anterior face of
petiole meet at or near right angle, (4) in dorsal view, posterior face of
petiole distinctly wider than distance between tips of superior propodeal spines, and (5) longest hairs on mesosoma approaching to slightly exceeding MOD uniquely
characterize this species.
Measurements
– lectotype (n
= 31). HL 1.25 (1.17-1.41); HW 1.26 (1.14-1.33); MOD 0.26
(0.25-0.30); OMD 0.28 (0.24-0.33); SL 0.84 (0.87-0.99);
PNW 0.82 (0.75-0.92); HFL 1.09 (1.03-1.27); ML 1.38 (1.33-1.55); PW 0.38
(0.34-0.43); PPW 0.49 (0.46-0.54).
Indices: SI 66.67 (70.08-85.09); CI
100.80 (92.37-105.69); OI 20.63 (20.49-24.56); HFI 86.51 (83.46-103.31).
Description. Head subquadrate to
quadrate (CI = 92.37-105.69), widest just posterior to eye; posterior margin
flat to weakly concave. Longitudinal
cephalic rugae prominent, occasionally weakly rugoreticulate especially near posterior margin;
approximately 8-10 coarse longitudinal rugae between
frontal lobes; in full-face view median rugae not
diverging towards posterior corners of head.
In side view, area posterior to eyes rugose to moderately rugoreticulate,
rugae not converging toward vertex; vertex rugose.
Cephalic interrugal spaces moderately to
strongly granulate, dull to weakly shining.
Anterior margin of clypeus moderately to strongly
concave, dorsal surface with numerous subparallel
longitudinal rugae; lacking small lobe that projects
dorsally from anterior margin of antennal fossa. Mandible with six teeth; mandibular
dorsum coarsely striated. Up to several
moderately long, curved, bristle-like, yellow-brown to brownish hairs project
from anterior margin of clypeus and basolateral
margin of mandibles. MOD
ranging from 0.20-0.25x HL. Eyes
in profile situated anterior to middle of head, OMD = 0.80-1.19x MOD. Antennal scapes moderately
long (SI = 66.67-85.09), failing to reach vertex by 1.0-1.5x length of basal
funicular segment; entire scape with strong
longitudinal striae, dull to weakly shining. basal flange of scape flattened and well developed with carinate
margin. Psammophore
poorly developed, consisting of short to medium length hairs scattered across ventral
side of head.
Mesosomal profile convex;
all mesosomal surfaces with highly irregular rugae, rugoreticulate, or
vermiculate. Metanotal sulcus not
impressed. Dorsum of promesonotum and sides of pronotum
rugoreticulate to vermiculate. Mesopleura with
irregular rugae angling posterodorsally
to rugoreticulate. Dorsum of propodeum with wavy to irregular transverse rugae that traverse anteroventrally,
becoming more irregular on sides.
Superior propodeal spines moderately
long, acuminate, connected by well defined keel; spine length approximately 0.7-0.8x
distance between bases. Inferior propodeal spines well-developed, acuminate, length
approximately 0.5-1.0x that of superior spines, base wider than length of
superior spines; inferior and superior spines connected by weak crest. Propodeal spiracles ovoid to circular facing posterad. Interrugal spaces
on mesosoma moderately granulate, weakly shining to
smooth and strongly shining. Legs moderately coriarious, weakly shining.
Petiolar peduncle about
as long as petiole, anteroventral margin with a weakly
to strongly developed triangular process.
In side view, petiolar node asymmetrical with
anterior surface shorter than posterior surface; apex of node weakly rounded to
subangulate; anterior face meeting peduncle at or
near right angle. In dorsal view, petiolar node longer than wide, widest near middle, narrowing
to spatulate to rounded anterior margin; maximal width
of posterior face greater than distance between tips of superior propodeal spines; dorsum and sides strongly rugoreticulate to vermiculate, interrugal
spaces granulate, dull to weakly shining.
Dorsum of postpetiole convex in profile; in
dorsal view, postpetiole robust, widest at or near
posterior margin, narrowing from near middle to weakly truncate anterior
margin; maximal width slightly greater than length; dorsum and sides weakly to
moderately rugoreticulate or with several irregular
longitudinal to oblique rugae, interrugal
spaces moderately to strongly granulate, dull to weakly shining. Ventral process of postpetiole large, bulbous, height similar to dorsal
portion of postpetiole. First gastral tergum weakly to strongly coriarious,
dull to weakly shining to smooth and strongly shining; anterior margin
sometimes with weak longitudinal striae.
Erect
yellow-brown to brownish pilosity moderately abundant
on head, variable in length, mostly short to medium long, often with one or
more longer hairs that approximate MOD. Moderately abundant suberect to semidecumbent pilosity on scape, abundant decumbent hairs on funicular segments. Legs with moderately
abundant semidecumbent brownish setae. Mesosoma, petiole, postpetiole, gastral terga with moderately
dense, erect setae, mostly similar in length, longest approaching to slightly
exceeding MOD; hairs on propodeum less dense. Concolorous tan to tannish-brown with darker gaster.
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 Figure x.
This caste is characterized by: (1) petiole and postpetiole
very wide (petiole > 0.50 mm, postpetiole
> 0.70 mm; see Figure x), (2) posterior face of petiole granulate-punctate, and (3) mesoscutum and mesoscutellum longitudinally rugose.
Measurements
– (n = 4). HL 1.19-1.35; HW 1.24-1.30;
MOD 0.30-0.32; OMD 0.27-0.31; SL 0.69-0.75; PNW 1.00-1.03; HFL 0.92-0.95; ML
1.56-1.65; PW 0.54-0.57; PPW 0.71-0.76. Indices: SI 54.33-57.69; CI 95.38-106.72; OI
23.08-25.20; HFI 72.44-76.61.
Male. Unknown.
Additional material examined. ARGENTINA: Córdoba: Alta Gracia la
Granja, Sierras de Córdoba, no date (MACN). Entre Ríos: El Palmar,
25m, Feb. 7, 1999 (RAJC); Victoria, 80’, Jan. 6, 2008; Jan. 12, 2011 (RAJC). Misiones:
Loreto, no date (MACN). BOLIVIA: Beni: Reyes,
Nov. 22, 1921 (USNM); Dpto. Unknown:
San Antonio, Nov. 22, 1921 (USNM). BRAZIL:
Mato
Grosso: Belo Horizonte, Nov. 4, no year (CASC;
MCZ). Minas Gerais: 6 km E Mariana Mtns,
1000m, May 16, 1971 (MCZ). Rio Grande do Sul: Porto
Alegre, Mar. 24, 1971 (MZUSP). São Paulo: Fazanda
Itaquera, Nova Europa, no date (MZUSP); Pindamonhangaba, Aug. 25, 1961
(MZUSP). Estado
Unknown: Pirafron?, no date (MZUSP).
Etymology. The
specific epithet, abdominalis (from Latin, abdomen- = abdomen),
appears to be derived from the enlarged postpetiole
on this species, which Santschi described as wider
than long for the worker and even larger and more pronounced in the queen.
Discussion. Pogonomyrmex abdominalis co-occurs
with both of the other two P. naegelii-group
species. Pogonomyrmex abdominalis can be distinguished from P. tenuipubens
based on the following characters: (1) hairs on the mesosoma
and psammophore are coarse and longer than width of
the intercephalic rugae,
and (2) approximately 8-10 coarse rugae between frontal
lobes. In P. tenuipubens, the hairs on the mesosoma and psammophore are thin
and delicate, and their maximal length is similar to or less than the width of intercephalic rugae, and more
than 15 fine rugae between frontal lobes. Pogonomyrmex abdominalis is distinguished from P. naegelii based on the following
characters: (1) usually larger (HW = 1.14-1.33 mm; Figure x), (2) lacking a
small lobe that projects dorsally from anterior margin of antennal fossa, (3) peduncle and anterior face of the petiole meet
at or near a right angle, and (4) the posterior face of the petiole wider than distance
between tips of the superior propodeal spines. In P. naegelli, the body is usually smaller (HW = 1.05-1.23
mm), a small lobe projects dorsally from the anterior margin of the antennal fossa, the peduncle and anterior face of the petiole meet
at an obtuse angle, and width of the posterior face of petiole is similar to or
only slightly greater than distance between tips of the superior propodeal spines.
In his description,
Santschi listed Alta Gracia,
Córdoba, as the type
locality for P. abdominalis, as did all
subsequent authors (see Gallardo,
1932; Kempf, 1972;
Kusnezov, 1951). However, labels on all syntypes
say, “Alta Gracia La Granja, Sierras de Córdoba”.
Alta Gracia and La Granja are small towns along
the east side of the Sierras de Córdoba that are separated
by about 75 km. Thus, the labels suggest
that the actual type locality was somewhere between these two pueblos.
REFERENCES