Technomyrmex difficilis

Nomenclature

Species: Technomyrmex difficilis Forel, 1892

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Diagnostic description

Diagnosis among workers of introduced and commonly intercepted species.

Antenna 12-segmented. Antennal scape length less than 1.5x head length. Eyes medium to large (greater than 5 facets); eye length not distinctly greater than length of erect hairs on frontal carinae. Antennal sockets and posterior clypeal margin separated by a distance less than the minimum width of antennal scape. Mandible lacking distinct basal angle. Dorsum of mesosoma with metanotal groove, but never with a deep and broad concavity; erect hairs present. Propodeum and petiolar node both lacking a pair of short teeth. Propodeum lacking posteriorly projecting protrusion; with dorsal surface distinctly shorter than posterior face. Waist 1-segmented (may be hidden by gaster). Petiolar node appearing flattened. Gaster armed with ventral slit; with five plates on its dorsal surface. Distinct constriction not visible between abdominal segments 3+4. Hairs Dorsum of head with one pair of long and thin erect hairs posterior to eye. Pronotum with 1 pair of erect hairs. Mesonotum with erect hairs. Propodeum with 2 pairs of erect hairs. Color uniformly dull brown with paler antennae, trochanters and tarsi; hind tarsus distinctly lighter in color than hind femur.

Technomyrmex difficilis can be distinguished from Brachymyrmex species, with which it bears superficial resemblance, by the 12-segmented (versus 9-segmented) antenna, and by the presence of a ventral slit (versus acidopore) on the gaster tip. It can be differentiated from Technomyrmex species by the absence (versus presence) or erect hairs on the mesosoma, and by the gaster which has 4 plates on the dorsal surface and 6 on the ventral surface (versus 5 plates on both surfaces). It is most easily differentiated from Tapinoma sessile by the bicolored with dark head and light body, gaster and appendages (versus uniform brown color). Technomyrmex difficilis is distinguished from its fellow introduced congeners by the following combination of characters: (1) Dorsum of head with one pair of long and thin erect hairs posterior to eye; (2) 1 pair of erect hairs on pronotum, 2 pair of propodeum, erect hairs present on mesonotum,; (3) hind tarsus distinctly lighter in color than hind femur; and (4) eye length is not distinctly greater than length of erect hairs on frontal carinae.

Look alikes

Brachymyrmex, Tapinoma sessile, Technomyrmex albipes, Technomyrmex pallipes, Technomyrmex vitiensis

Adults inside the brood nest. This species has been introduced by human activities to warmer regions around the world. Photo by ©Alexander L. Wild, alexanderwild.com	A worker carries a pupa. Photo by ©Alexander L. Wild, alexanderwild.com
Adult tends to aphids for honeydew. Photo by ©Alexander L. Wild, alexanderwild.com	A healthy brood nest. Photo by ©Alexander L. Wild, alexanderwild.com
Lateral view of head, adult. Note eyes and cephalic hairs (arrow).	Lateral view of leg, adult worker. The metatarsus is pale in color and contrasts sharply with the darker brown hind tibia and femur. Separates Technomyrmex albipes, T. difficilis and T. vitiensis from T. pallipes.
Lateral view of thorax / mesosoma, adult worker. Mesonotum hairs.	Lateral view of pronotum, adult worker. Pronotum with one pair of erect hairs that differ from the appressed pilosity. Separates Technomyrmex difficilis, T. vitiensis, and T. pallipes from T. albipes. However, these hairs can be easily rubbed off prior to examination.
Lateral view of mesonotum, adult worker. Mesonotum with one pair of erect hairs. Separates Technomyrmex difficilis and T. pallipes from T. albipes and T. vitiensis. However, the hairs of some specimens can often be rubbed off prior to examination.	Lateral view of propodeum, adult worker. The propodeal declivity has two pairs of erect hairs. Separates Technomyrmex albipes, T. difficilis and some specimens of T. pallipes from T. vitiensis.