Technomyrmex strenuus

An arboreal species that is sparsely collected and poorly known biologically.

Identification
Bolton (2007) - A member of the Technomyrmex strenuus group. T. strenuus is a member of a complex of four closely related, small, arboreal species that together are characterised by dense pilosity all over the body (including the propodeal dorsum), strongly reduced sculpture so that the head capsule is glassy smooth and gastral tergites 1 - 2 are smooth and shining, and relatively short scapes (SI range of all four species 81 - 91). Of the four, Technomyrmex mandibularis is immediately diagnosed by its possession of a mandibular groove, the presence of short setae on the scapes and the presence of dense cephalic pubescence. The other three species Jack all these characters.

Technomyrmex convexifrons has standing setae on the dorsal (outer) surfaces of the middle and hind tibiae, at least one on each tibia in the apical half. T. strenuus and Technomyrmex tatius lack such tibial setae. These two are easily separated as the anterior clypeal margin of strenuus is almost transverse while that of tatius has a marked median indentation, the only member of the complex to display such a feature.

Material of all four species is very sparse and it is not known if they develop female intercastes. However, the syntype-series of strenuus contains an apparent queen, with fully developed mesosomal sclerites but which is apterous. This may represent a genuine ergatoid queen or be the most morphologically queen-like of an otherwise unknown inter caste sequence.

Distribution
Bolton (2007) - The four species mentioned in the identification section above are known only from the Malay Peninsula, Borneo and Sumatra but there is also an unnamed species of this complex present in Sri Lanka. It is represented by a single specimen collected by Bingham (in BMNH) that has its head missing, so its identity can not be ascertained, but it does prove that the distribution of this complex is much wider than is implied by the few complete specimens that are currently available.

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

Nomenclature

 *  strenuus. Technomyrmex strenua Mayr, 1872: 147 (w. ergatoid q.) BORNEO. Forel, 1911a: 46 (m.). See also: Bolton, 2007a: 100.

Worker
Bolton (2007) - TL 2.3 - 3.1, HL 0.56 - 0.68, HW 0.55 - 0.70, SL 0.48 - 0.60, PW 0.36 - 0.46, WL 0.68 - 0.86 (5 measured). Indices: CI 95 - 102, SI 86 - 91, OI 20 - 24, EPI 80 - 95, DTI 110 - 120.

Frontal carina with 2 - 3 setae. Posterior to this the head with 5 - 6 pairs of varying length on the dorsum itself and with an additional 4 - 6 setae across the posterior margin; longest setae at least equal to maximum diameter of eye, usually somewhat longer. Scapes without setae. Dorsum of head glassy smooth, unsculptured except for pits from which setae arise, and with sparse minute pubescence that does not conceal the surface. In full-face view the anterior clypeal margin almost transverse, the posterior margin of the head very feebly concave medially; outer margins of eyes just break the outline of the sides of the head. Pronotal dorsum mostly smooth, with only vestiges of sculpture; dorsal surfaces of mesonotum and propodeum minutely: and very densely reticulate-punctulate, the latter slightly more densely so than the former. Number of setal pairs on mesosoma: pronotum 3 - 4; mesonotum 4 6; propodeum 4 - 5; lateral margin of propodeal declivity 2 - 3. With propodeum in profile the junction of dorsum and declivity bluntly angular. Dorsal (outer) surfaces of middle and hind tibiae without setae. Gastral tergites 1 - 4 each with numerous setae, the longest of them longer than the maximum diameter of the eye. Gastral tergites 1 - 2 unsculptured, smooth and polished; pubescence on these sclerites very sparse. Head and gaster dark brown to black; most of mesosoma slightly lighter, the colour usually varying in intensity in different areas; pronotum slightly lighter than the remainder and the propodeum often the same colour as the gaster.

Type Material
Bolton (2007) - Syntype workers and ergatoid queen, Malaysia: Sarawak, 1865 - 66 (G. Doria) [examined].

References based on Global Ant Biodiversity Informatics

 * Bolton B. 2007. Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker caste. Contributions of the American Entomological Institute 35(1): 1-150.
 * Bolton, B. "Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker caste." Contributions of the American Entomological Institute 35, no. 1 (2007): 1-149.
 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * Emery C. 1887. Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia. [part]. Ann. Mus. Civ. Stor. Nat. 24(4): 209-258.
 * Emery C. 1913. Hymenoptera. Fam. Formicidae. Subfam. Dolichoderinae. Genera Insectorum 137: 1-50.
 * Emery, C. "Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 4, no. 24 (1887): 209-258.
 * Forel A. 1911. Fourmis de Bornéo, Singapore, Ceylan, etc. récoltées par MM. Haviland, Green, Winkler, Will, Hose, Roepke et Waldo. Rev. Suisse Zool. 19: 23-62.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
 * Wheeler W. M. 1919. The ants of Borneo. Bulletin of the Museum of Comparative Zoology 63:43-147.