Strumigenys emmae

Identification
Bolton (2000) - Within the emmae-group, emmae is recognised by its combination of short mandibles, broad head, short 4-merous antennae with distinctly angular leading edge on the scape, presence of orbicular hairs on the promesonotum as well as on the cephalic dorsum, absence of erect hairs on the occipital margin and lack of a strong second preapical tooth located between the apicodorsal tooth and the long spiniform preapical tooth.

Distribution
Bolton (2000) - This very successful pantropical tramp species was described and discussed by Brown (1949a) and Bolton (1983). Previous distribution records include Hawaii, Guam, U.S.A., Puerto Rico, West Indies, Cuba, Bahamas, Surinam, Ghana, Equatorial Guinea, India, West Malaysia, Sumatra, Singapore, Philippines, Sulawesi, New Guinea, Solomon Islands, Australia, Vanuatu, Samoa (Brown, 1949a; Wilson & Taylor, 1 967; Kempf, 1972; Taylor, 1976; Bolton, 1983; Deyrup, 1997). A recent survey of Florida by Deyrup & Deyrup (1999) shows that emmae is widely distributed in the state.

This taxon was described from Antilles. It is also found in New Caledonia, Australia, Philippines, Ecuador, New Guinea, Suriname, Belize, Costa Rica, Dominican Republic, Puerto Rico, China, India, Comoros, Seychelles, Réunion, Mayotte, Madagascar, Equatorial Guinea, Ghana, Japan, Viet Nam, Indonesia, Malaysia, Yemen, Solomon Islands, Vanuatu, Guam, Samoa, Tonga, Saint Lucia, Barbados, Marshall Islands, Micronesia (Federated States of), Northern Mariana Islands, Borneo and Hawaii.

Nomenclature

 *  emmae. Epitritus emmae Emery, 1890b: 70, pl. 8, fig. 6 (w.) ANTILLES. Wheeler, W.M. 1908a: 149 (q.). Combination in Quadristruma: Brown, 1949b: 48; in Strumigenys: Bolton, 1999: 1674. Senior synonym of clypeatus, malesiana, wheeleri: Brown, 1949b: 48. See also: Bolton, 1983: 400; Bolton, 2000: 950.
 * clypeatus. Epitritus clypeatus Szabó, 1909: 27, fig. 1 (w.) NEW GUINEA. Junior synonym of emmae: Brown, 1949b: 48.
 * malesiana. Epitritus clypeatus var. malesiana Forel, 1913k: 83 (w.q.) INDONESIA (Sumatra). Junior synonym of emmae: Brown, 1949b: 48.
 * wheeleri. Epitritus wheeleri Donisthorpe, 1916a: 121 (w.) HAWAII. Junior synonym of emmae: Brown, 1949b: 48.

Worker
Bolton (2000) - TL 1.5 - 1.9, HL 0.40 - 0.46, HW 0.33 - 0.39, CI 80 - 88, ML 0.11 - 0.16, MI 26 - 35, SL 0.18 - 0.24, SI 56 - 62, PW 0.21 - 0.25, AL 0.40 - 0.48 (33 measured). Exposed length of fully closed mandible less than width of anterior clypeal margin. Preapical dentition of mandible somewhat variable: inner margin between the spiniform preapical tooth and the apicodorsal tooth may be unarmed, may have a low blunt tubercle or welt, or may have a tiny denticle (intermediates between these are known). Intercalary and preapical dentition may be obscured by the principal teeth when the mandibles are fully closed. Antenna with 4 segments; second funicular segment not obviously much longer than broad. Cephalic dorsum with orbicular hairs; upper scrobe margin fringed with similar hairs and with a clavate apicoscrobal hair. Occipital margin of head without short erect hairs. Leading edge of scape flattened and expanded into an obtuse angle or broad but shallowly convex lobe in the median third of its length. Pronotal humeral hair stiff, stout. Ground-pilosity of pronotal dorsum orbicular but the hairs tending to be smaller than on head. Mesonotum usually with a single pair of short erect hairs but these sometimes absent. Promesonotal dorsum reticulate-punctate, without longitudinal striae. Disc of postpetiole usually with weak sculpture at least in part, only rarely entirely smooth; sides of disc in dorsal view with projecting spongiform tissue. First gastral tergite with short suberect to erect stubbly hairs that are simple to feeble expanded apically. Basigastral costulae at least equal in length to postpetiole disc.

Type Material
Bolton (2000):

Holotype worker, ST THOMAS I. (Antilles).

Epitritus clypeatus Szabó, 1909: 1, figs. la, c. Syntype workers, NEW GUINEA: Berlinhafen (L. Biró); and SINGAPORE (L. Biró) [not seen].

Epitritus clypeatus var. malesiana Forel, 1913e: 83. Syntype workers and queen, INDONESIA: Sumatra (Buttel-Reepen) [not seen].

Epitritus wheeleri Donisthorpe, 1916: 121. Holotype worker, HAWAII: Oahu, Honolulu (R.C.L. Perkins) [not in, holotype lost].

Additional References

 * Wetterer, J.K. 2012. Worldwide spread of Emma's dacetine ant, Strumigenys emmae (Hymenoptera: Formicidae). Myrmecologial News 16: 69-74.