Pheidole subarmata

Pheidole subarmata favors moist soil in open places, including habitats seriously disturbed by human activity—such as the edges of dirt roads, agricultural fields, coconut groves, secondary rainforest, city parks, and seashores. When exploring in the deeper rainforest is done, it is usually easy for the collector to add subarmata to his list by searching adjacent roads and fields. On St. Vincent, the indefatigable H. H. Smith (in Forel 1893j) found colonies of this species from sea level to 460 m. The nests are usually constructed in open soil or soil beneath rocks or sod, but also occasionally in pieces of rotting wood. When in the open they are marked by irregular accumulations of excavated soil. The galleries are irregular and difficult to follow by excavation, although I was able to do so in a Costa Rican banana plantation by digging a lateral pit and shaving the soil away from the side. The colonies are relatively small, with workers numbering probably only in the hundreds. On St. Vincent, H. H. Smith observed workers foraging on the ground and bushes. He found colony-founding queens in November. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
Pheidole subarmata is one of the most abundant and wide-ranging species of New World Pheidole, as evidenced by the heavy synonymic fouling cited above. It has been recorded from Veracruz, Mexico, south to Santa Catarina in southern Brazil, and widely through the West Indies, including the Bahamas, Cuba, Puerto Rico, and some of the Lesser Antilles, including St. Vincent and Grenada. It has also been found on Cocos Island off the Pacific Coast of Costa Rica. (Wilson 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bahamas, Barbados, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, French Guiana, Greater Antilles, Grenada, Guadeloupe, Guatemala, Haiti, Honduras, Mexico, Panama, Paraguay, Puerto Rico, St. Vincent, Trinidad and Tobago.

Biology
Wheeler (1905), Bahamas - Several soldiers and workers, taken in and about Nassau, N. P. (Queen's Staircase, Fort Charlotte, etc.), from small nests in grassy places and occasionally under stones.

Worker
Minor

Images from AntWeb
Major

Nomenclature

 *  subarmata. Pheidole subarmata Mayr, 1884: 37 (s.w.) FRENCH GUIANA. Senior synonym of borinquenensis, cornutula, dentimentum, elongatula, hondurensis, imbecillis, nassavensis, nefasta: Brown, 1981: 526. See also: Wilson, 2003: 759.
 * cornutula. Pheidole cornutula Emery, 1890b: 52 (footnote), pl. 5, figs. 14, 15 (s.) PARAGUAY. Forel, 1901e: 365 (w.); Santschi, 1923d: 62 (q.m.); Goni, Zolessi & Imai, 1983: 365 (k.). Junior synonym of subarmata: Brown, 1981: 526.
 * elongatula. Pheidole subarmata var. elongatula Forel, 1893g: 408 (s.w.q.m.) ANTILLES. Junior synonym of subarmata: Brown, 1981: 526.
 * nassavensis. Pheidole subarmata var. nassavensis Wheeler, W.M. 1905b: 92 (s.w.) BAHAMAS. Junior synonym of subarmata: Brown, 1981: 526.
 * imbecillis. Pheidole cornutula var. imbecillis Emery, 1906c: 151 (s.w.) ARGENTINA. Junior synonym of subarmata: Brown, 1981: 526.
 * borinquenensis. Pheidole subarmata var. borinquenensis Wheeler, W.M. 1908a: 133, pl. 12, figs. 19-21 (s.w.) PUERTO RICO. Junior synonym of subarmata: Brown, 1981: 526.
 * hondurensis. Pheidole (Elasmopheidole) hondurensis Mann, 1922: 25, fig. 12 (s.w.) HONDURAS. Junior synonym of subarmata: Brown, 1981: 526.
 * dentimentum. Pheidole cornutula var. dentimentum Santschi, 1929d: 285 (s.) BRAZIL. Junior synonym of subarmata: Brown, 1981: 526.
 * nefasta. Pheidole subarmata var. nefasta Santschi, 1929d: 285 (s.w.) BRAZIL. Junior synonym of subarmata: Brown, 1981: 526.

Description
From Wilson (2003): DIAGNOSIS Similar to Pheidole allarmata, Pheidole cramptoni, Pheidole hasticeps, Pheidole synarmata and Pheidole triplex, differing from them and other Pheidole by the following combination of traits.

Major: head elongate; frontal lobes seen from the side triangular, pointing slightly downward; pronotum low and rounded, descending into the mesonotum in a weakly convex, continuous curve; propodeal spines very small; carinulae limited to the anterior half of the head, and those immediately mesad to the eyes reaching only to the posterior margins of the eyes; rest of head and body smooth and shiny.

Minor: occiput broad, lacking nuchal collar; propodeal spines reduced to denticles; except for circular carinulae of the antennal fossa, entire head and body smooth and shiny. I have confirmed most of the synonymies made by William L. Brown (1981) and listed above.

MEASUREMENTS (mm) Paralectotype major (Santa Catarina, Brazil): HW 0.94, HL 1.18, SL 0.50, EL 0.14, PW 0.54. Lectotype minor: HW 0.42, HL 0.48, SL 0.42, EL 0.08, PW 0.28. COLOR Major: reddish yellow to dark brown, including appendages; on some specimens at least, there is a diffuse round light brown spot on the vertex, as illustrated.

Minor: light yellowish brown, appendages yellow.



'''Figure. Upper: major. Lower: minor. COLOMBIA: Yumbo (compared with syntypes from Santa Catarina, Brazil, by E. O. Wilson.) Scale bars = 1 mm.'''

Etymology
L subarmata, presumably, less well armed, referring to the small propodeal spines. (Wilson 2003)

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