Strumigenys gyrogenys

Identification
Bolton (2000) - A member of the Strumigenys chapmani-group. S. gyrogenys is obviously a very close sibling of Strumigenys rotogenys, and I am not sure that I have made the right decision in separating the two. However, much material of rotogenys is available, is consistent in its diagnostics, and consistently differs from the admittedly few specimens of the rarer gyrogenys that are currently available. The validity of the latter name can be re-tested if ever good series are collected, but for the present there are no intermediates.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia.

Nomenclature

 *  gyrogenys. Strumigenys gyrogenys Bolton, 2000: 768 (w.) BORNEO.

Worker
Holotype. TL 3.4, HL 0.99, HW 0.98, CI 99, ML 0.56, MI 57, SL 0.50, SI 51, PW 0.36, AL 0.80. Very closely related to rotogenys and answering the description of that species, but with mandibles that are longer and more slender, and with a relatively longer apicodorsal fork tooth. The two differ as follows.

S. gyrogenys: Mandibles relatively longer, MI 56-57. Mandible somewhat more slender, its maximum width 0.14 X ML. Apicodorsal tooth of mandible longer and narrower, length from j unction with inner margin of mandible to apex 2.80-3.10 X maximum width of mandible. With mandibles fully closed the upper apicodorsal tooth of the overlapping pair with the apical half or more of its length projecting beyond the outer margin of the opposing lower mandible.

S. rotogenys: Mandibles relatively shorter, MI 45-51. Mandible somewhat broader, its maximum width 0.18 X ML. Apicodorsal tooth of mandible shorter and stouter, length from junction with inner margin of mandible to apex 2.00-2.25 X maximum width of mandible. With mandibles fully closed the upper apicodorsal tooth of the overlapping pair with the apical one-quarter or less of its length projecting beyond the outer margin of the opposing lower mandible.

Paratypes. TL 3.3-3.5, HL 0.90-1.00, HW 0.88-0.98, CI 95-99, ML 0.50-0.57, MI 56-57, SL 0.46-0.52, SI 52-54, PW 0.32-0.36, AL 0.78-0.82 (3 measured).

Type Material
Holotype worker, Malaysia: Sarawak, 4th Div., Gn. Mulu N. P., 200 m., 8.vi.1978, limestone forest, pitfall trap (H. Vallack).

Paratypes. 1 worker with same locality as holotype but 14.iii.1978, limestone forest, leaf litter (H. Vallack); 1 worker with same locality as holotype but v-viii.1978, BM 1978-49, base camp (P. M. Hammond & J.E. Marshall); 1 worker Sarawak, 4th Div., G. Mulu Nat. Pk, RGS Expd., Long Pala, 6.x.1977, leaf litter, lowland rainforest (B. Bolton) (BMNH, ).