Pseudomyrmex seminole

Possible a facultative, temporary social parasite of Pseudomyrmex pallidus.

Identification
Ward (1985) - P. seminole occurs sympatrically with the closely related Pseudomyrmex pallidus. Workers of P. seminole may be recognized by the less convergent frontal carinae (MFC ≥ 0.029 in P. seminole, ≤  0.024 in P. pallidus), shorter eyes, and weakly angulate median portion of the anterior clypeal margin. The angulate clypeus of P. seminole tends to be a little more produced than that of P. pallidus workers (CDI 0.040-0.064 in P. seminole, 0.030-0.054 in P. pallidus). On average, the petiole and postpetiole of P. seminole are longer and more slender than those of P. pallidus, but there is sufficient variation in both species that the relevant metrics overlap broadly. Differences between the queens of the two species are more pronounced and the male genitalia of P. seminole are quite distinct (see keys to queens and males).

Distribution
Gulf coast of USA and Mexico. Also known from the Bahamas.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Biology
Ward (1985) - I have collected nests of P. seminole in dead stalks or culms of Andropogon, Heterotheca subaxillaris, Uniola paniculata, and an unidentified woody legume. None of these nests was polygynous; some were queenless, indicating that this species is polydomous.

On Padre Island, east Texas P. seminole is patchily distributed in a continuous population of Pseudomyrmex pallidus. Both species use the same nest sites (Heterotheca stalks and Uniola culms). I have observed incipient P. seminole colonies consisting of (i) a single, dealate queen, (ii) a single, dealate queen with brood, and (twice) (iii) a single dealate queen in association with P. pallidus workers. In one of the latter instances a dealate P. pallidus queen and five workers occupied one Uniola internode, while the P. seminole queen occupied an adjacent cavity; in the second instance, the P. seminole queen coexisted with seven P. pallidus workers (but no queen) plus brood of unknown identity, in a single dead Heterotheca stalk. These observations suggest that P. seminole may be a facultative, temporary social parasite of P. pallidus.

Alates or alate pupae have been collected in most months of the year, indicating a rather continual production of sexuals.

Nomenclature

 *  seminole. Pseudomyrmex seminole Ward, 1985b: 237, figs. 18, 21, 28, 44, 45 (w.q.m.) U.S.A. Wheeler, G.C. & Wheeler, J. 1991b: 90 (l.).

Worker
Ward (1985) - Measurements (n = 26): HL 0.98-1.16. HW 0.87-0.96, MFC 0 .029-0.042, CI 0.81-0.89, OI 0.57-0.63, REL 0.43-0.48, REL2 0.53-0.56, OOI 1.04-1.94, VI 0.75-0.85, FCI 0.031-0.47, SI 0.42-0.47, SI2 0.75-0.85, FI 0.38-0.44, POI 1.05-1.40, MPI 0.017-0.045, NI 0.53-0.62, PLI 0.46-0.53, PWI 0.39-0.47, PPWI 0.93-1.09.

DPL 0.75-0.87. MP 0.015-0.042, CDI 0.040-0.064, PLI2 1.11-1.34, PHI 0. 56-0.67, PWI2 0.50-0.59, PPWI2 0.48-0.57.

Diagnosis: —Relatively large species, with broad head (HW 0.87-0.96, CI 0.81-0.89); median portion of anterior clypeal margin obtusely (and weakly) angulate, sharply angulate laterally; distance between frontal carinae subequal to, or slightly less than, basal width of scape; eyes relatively short (REL 0.43-0.48); occipital margin comvex or flat, in full face, dorsal view; lateral margins of pronotum rounded; metanotal groove wide but shallow; basal face of propodeum rounding into declivitous face, the former equal to, or longer than, the latter; petiole and postpetiole long and slender, the former with a distinct anterior peduncle and (usually) prominent, rounded anteroventral tooth. Mandibles very weakly striate, with scattered punctures; head subopaque to sublucid, densely punctulate on a coriarious background; mesosoma and petiole subopaque, coriarious-punctulate, becoming coriarious-imbricate laterally; postpetiole and gaster subopaque, with numerous fine piligerous punctures. Erect pilosity sparse, lacking on mesonotum and Propodeum; one to several pairs of erect setae on dorsum of head, pronotum, petiole, postpetiole and abdominal tergite IV. Fine appressed hairs present on most parts of body, and forming a rather dense mat on abdominal tergite IV. Body orange brown; mandibles and apices of appendages variubly paler.

Type Material
Ward (1985) - Holotype worker: John Pennekamp State Pk., Munroe Co., Florida. < 5 m. 14.ix.1982, ex colony in dead Andropogon culm. roadside near mangrove. P.S. Ward acc. no. 5723. HW 0.90, HL 1.05, EL 0.50, PL 0.59, PH 0.29.

Paratype workers, queens. males: Two nest series from John Pennekamp St. Pk., Munroe Co., Florida. 14.ix.1982, ex dead Andropogon culms. P.S. Ward acc. nos. 5722, 5723; two nest series and ground foragers from 12 mi N. Key Largo. Munroe Co., Florida. 10.i.1979, ex dead Andropogon culms. and foraging on ground. P.S. Ward acc. nos. 3199, 32002, 3203 (,, MCZ, , , ).