Technomyrmex rotundiceps

A sample from Borneo was collected from the leaf litter of a swamp forest. Material from Pasoh Forest Reserve was collected by pyrethrum fogging of a forest tree.

Identification
Bolton (2007) - A member of the T. pallipes complex in the Technomyrmex albipes group. This species is quite distinct from Technomyrmex albipes, with which it was previously associated. Its eyes are located distinctly more posteriorly (EPI in albipes is 70 - 88), there is a pair of setae on the dorsum of the head behind the level of the eye and rotundiceps workers tend to average somewhat larger (albipes HL 0.56 - 0.63, HW 0.52 - 0.58). Also, the hind basitarsus is mostly dark brown to black in rotundiceps, the same colour as the tibia. This apparently trivial character appears consistent and has not been seen in genuine albipes, where the hind basitarsus is entirely yellow to white and contrasts with the dark brown to black tibia.

The relatively posteriorly placed eyes are duplicated in Technomyrmex brunneus but that species has a conspicuous mandibular groove (absent in rotundiceps) and lacks setae on the dorsal head behind the level of die posterior margin of the eye. The tramp Technomyrmex difficilis appears closely related but here the eyes are somewhat larger and located further forward (OI 25 - 30, EPI 72 - 86), the sides of the head are not so distinctly convex and the hind tarsal segments are uniformly pale.

Distribution
Java, Sabah (Borneo).

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

Nomenclature

 *  rotundiceps. Technomyrmex albipes subsp. rotundiceps Karavaiev, 1926d: 443 (w.) INDONESIA (Java). Raised to species: Bolton, 2007a: 99.

Worker
Bolton (2007) - TL 2.6 - 2.7, HL 0.62 - 0.68, HW 0.56 - 0.65, SL 0.54 - 0.66, PW 0.38 - 0.43, WL 0.76 - 0.86 (6 measured). Indices: CI 90 - 97, SI 92 - 102, OI 24 - 25, EPI 100 - 110, DTI 122 - 126.

Frontal carina with 2 setae. Dorsum of head posterior to this with a single pair of setae, in profile located just over half way between level of posterior margin of eye and the posterior margin of the head, not at the posterior margin; this pair of setae shorter than the posterior seta on the frontal carina. With head in full-face view the anterior clypeal margin with a very weak, shallow median indentation; sides distinctly convex, broadest across the eyes; posterior margin of head with a small shallow indentation medially. Eyes located at or behind the midlength, EPI 100 or more; outer margin of eye just fails to break the outline of the side in full-face view. With mesosoma in profile the mesonotal outline is evenly curved, without a distinct step or angle in the outline that defines conspicuous dorsal and declivitous faces. Dorsum and declivity of propodeum meet in an angle in profile. Number of setal pairs on mesosoma: pronotum 2 - 3; mesonotum 1 - 2 (usually 2, one pair anterior and the other posterior on the sclerite; when only one pair present it is the posterior pair); propodeal dorsum 0; lateral margins of propodeal declivity 2 - 3. Gastral tergites 1 - 4 each with numerous setae, distributed everywhere on the sclerites; maximum length of setae on first gastral tergite is equal to or slightly greater than the maximum diameter of the eye. Head, mesosoma, petiole and gaster blackish brown to black. Coxae, femora and tibiae the same colour as the mesosoma or very nearly so; never with strongly contrasting lighter coxae. Basal two-thirds of hind basitarsus dark brown to black, the same colour as the tibia; apical third and tarsomeres 2 - 5 yellow.

Type Material
Bolton (2007) - Syntype workers, Indonesia: Java, Tjampea, no. 2390 (Karavaiev) [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
 * Karavaiev V. 1926. Ameisen aus dem Indo-Australischen Gebiet. Treubia 8: 413-445.
 * Katayama M., K. Kishimoto-Yamada, H. O. Tanaka, T. Endo, Y. Hashimoto, Sk. Yamane, and T. Itioka. 2015. Negative correlation between ant and spider abundances in the canopy of a Bornean tropical rain forest. Biotropica (in press).
 * 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
 * Shattuck S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112: i-xix, 1-241.