Strumigenys perplexa

Bolton (2000) - By far the most common and widely distributed dacetine in Australia, S. perplexa also occurs in New Zealand and on Lord Howe Island, Norfolk Island and Philip Island. It is known to be the host species of the socially parasitic in the first two of these localities (Brown, 1955; Taylor, 1968a).

Identification
Bolton (2000) - A member of the signeae complex in the Strumigenys godeffroyi-group. Among the Austral members of the signeae-complex perplexa, together with Strumigenys geryon, Strumigenys gryphon, Strumigenys cingatrix and Strumigenys deuteras, are characterised, and easily recognised, by the 3 or 4 distinct pairs of stiffly erect stout hairs on the mesonotum. Of these, geryon and gryphon have numerous long slender hairs on the first gastral tergite that are finely filiform to flagellate, whereas gastral hairs in the remainder are short, stiffly erect and tend to be blunt apically. S. perplexa is distinguished from its closest congeners, cingatrix and deuteras by the characters given in the key, but see also the notes under cingatrix.

Of all the large amount of perplexa material examined the vast majority has MI 40-48. However, a few samples, mostly from Queensland and northern New South Wales, have shorter mandibles, MI 34-38. These samples also tend to be dark in colour, have a head that on average is somewhat narrower (CI 69-75, as opposed to CI 73-79), have a lateral alitrunk that is mostly unsculptured, and have fewer rows of hairs on the first gastral tergite; in extreme cases the hairs are reduced to merely an apical and a basal row. I had initially separated these few series as a sibling species, but the acquisition of more material produced individuals that were intermediate in one or more of these characters. In effect there may be two or even more close sibling species here. I can not resolve the problem at this time so all are retained here as a single species. A more detailed analysis in the future, when more of the supposed intermediates are available, may produce different results.

Distribution based on Regional Taxon Lists
Australasian Region: Australia, Lord Howe Island, New Zealand , Norfolk Island. Indo-Australian Region: Philippines.

Biology
Brown (1954) - Strumigenys perplexa shows surprisingly wide tolerance with respect to nesting sites, and has been found in dry, open woodland in South Australia and western Victoria, as well as in the dark, moist fern gullies in the hills east of Melbourne.

Nomenclature

 *  perplexa. Orectognathus perplexus Smith, F. 1876c: 491 (w.q.) NEW ZEALAND. Wheeler, G.C. & Wheeler, J. 1955a: 140 (l.); Wheeler, G.C. & Wheeler, J. 1973c: 214 (l.). Combination in Strumigenys: Emery, 1897c: 575. Senior synonym of antarctica: Emery, 1924d: 321; of leae: Brown, 1958h: 38. See also: Bolton, 2000: 967.
 * antarctica. Strumigenys antarctica Forel, 1892c: 338 (w.) NEW ZEALAND. Junior synonym of perplexa: Emery, 1924d: 321.
 * leae. Strumigenys leae Forel, 1913g: 182 (w.q.) AUSTRALIA (Tasmania). Junior synonym of perplexa: Brown, 1958h: 38.

Worker
Bolton (2000) - TL 2.0-2.6, HL 0.53-0.65, HW 0.42-0.49, CI 69-79, ML 0.21-0.30, MI 34-48, SL 0.29-0.36, SI 68-78, PW 0.25-0.30, AL 0.53-0.68 (35 measured).

With characters of signeae-complex. Apical fork of right mandible with a single small intercalary tooth. Apicoscrobal hair short, stiff and simple, straight or very shallowly curved. Cephalic dorsum sharply reticulate-punctate; 4-6 short standing hairs present along occipital margin, sometimes also with a short erect pair near highest point of vertex. Main row of projecting hairs on leading edge of scape spatulate and curved; secondary hairs on the edge distinctly shorter and very much more slender, the two sets of hairs easily distinguished. Pronotal humeral hair stiff and simple, straight to shallowly curved; pronotal dorsum with 1-3 pairs of stiffly erect simple hairs and mesonotum with 3 (rarely 4) similar pairs. Entire dorsal alitrunk finely and densely reticulate-punctate. Side of pronotum varying from entirely reticulate-punctate to almost entirely smooth. Katepisternum smooth, at most with weak traces of sculpture around extreme periphery. Metapleuron and side of propodeum varying from almost entirely reticulate-punctate to almost entirely smooth; commonly with a variably sized smooth patch that extends over the upper portion of the metapleuron and lower portion of the side of the propodeum. Postpetiole usually unsculptured and smooth but often with traces of sculpture peripherally; never entirely sculptured over whole disc. Hairs on first gastral tergite short and straight, simple and stiffly erect, apically blunt; hairs usually evenly distributed over sclerite but in some populations reduced medially and sometimes with only a basal and an apical transverse row. Basigastral costulae usually shorter than disc of postpetiole, less commonly about as long as disc.

Type Material
Bolton (2000) - Syntype workers and queen, NEW ZEALAND: Tairua, near Mercury Bay (Brown) [examined].



References based on Global Ant Biodiversity Informatics

 * Andersen A. N. 1983. A brief survey of ants in Glenaladale National Park, with particular reference to seed-harvesting. Victorian Naturalist 100(6): 233-237.
 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * Chong C-S., L. J. Thomson, and A. A. Hoffmann. 2011. High diversity of ants in Australian vineyards. Australian Journal of Entomology 50: 7-21.
 * Chong C. S., C. F. D'Alberto, L. J. Thomson, and A. A. Hoffmann. 2010. Influence of native ants on arthropods communities in a vineyard. Agricultural and Forest Entomology 12: 223-232.
 * Clay R. E., and K. E. Schneider. 2000. The ant (Hymenoptera: Formicidae) fauna of coastal heath in south-west Victoria: effects of dominance by Acacia sophorae and management actions to control it. Pacific Conservation Biology 6: 144-151.
 * Cumber, R. A. 1959. Distributional and biological notes on sixteen North Island species of Formicidae (Hymenoptera). New Zealand Entomologist 2(4):10-14.
 * Cumber, R.A. 1959. Distributional and biological notes on sixteen North Island species of Formicidae (Hymenoptera)
 * Forel A. 1913. Fourmis de Tasmanie et d'Australie récoltées par MM. Lae, Froggatt etc. Bull. Soc. Vaudoise Sci. Nat. 49: 173-195
 * Hoffmann, B. D., R. Graham, and D. Smith. 2017. Ant species accumulation on Lord Howe Island highlights the increasing need for effective biosecurity on islands. NeoBiota 34:41-52.
 * Lowery B. B., and R. J. Taylor. 1994. Occurrence of ant species in a range of sclerophyll forest communities at Old Chum Dam, north-eastern Tasmania. Australian Entomologist 21: 11-14.
 * Schnell M. R., A. J. Pik, and J. M. Dangerfield. 2003. Ant community succession within eucalypt plantations on used pasture and implications for taxonomic sufficiency in biomonitoring. Austral Ecology 28: 553565.
 * Sinclair J. E., and T. R. New. 2004. Pine plantations in south eastern Australia support highly impoverished ant assemblages (Hymenoptera: Formicidae). Journal of Insect Conservation 8: 277-286.
 * Taylor R. W. 1968. The Australian workerless inquiline ant, Strumigenys xenos Brown (Hymenoptera - Formicidae) recorded from New Zealand. New Zealand Entomologist 4(1): 47-49
 * Taylor R. W. 1987. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO (Commonwealth Scientific and Industrial Research Organization) Division of Entomology Report 41: 1-92.
 * Taylor R. W., and D. R. Brown. 1985. Formicoidea. Zoological Catalogue of Australia 2: 1-149.
 * Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
 * Wheeler WM. 1927. Ants of Lord Howe and Norfolk Islands. Proceedings of the American Academy of Arts and Sciences. 62.4: 120-153.
 * Wheeler, W. M. 1927. The ants of Lord Howe Island and Norfolk Island. Proc. Am. Acad. Arts Sci. 62: 121-153
 * Wheeler, William Morton. 1927. The Ants of Lord Howe Island and Norfolk Island. Proceedings of the American Academy of Arts and Sciences 62(4): 121-153
 * Wheeler, William Morton.1935.Checklist of the Ants of Oceania.Occasional Papers 11(11): 3-56