The species has been swept from low vegetation and also collected in pitfall traps, so, like many other species in this genus, arnoldinus probably nests in the earth, either directly or under stones, and forages both terrestrially and on plants. (Bolton 2007)
Bolton (2007) - T. arnoldinus is quite distinct among the Afrotropical fauna. The presence of transverse fine rugulose sculpture on the propodeal declivity is unique and immediately isolates the species. Beyond that its relationships are harder to decide. In terms of reduced sculpture on the head, pronotum and gaster it resembles Technomyrmex strenuus and its allies from the Oriental and Malesian regions, but the depth of the clypeal notch in arnoldinus exceeds what is usually seen in those species. The presence of setae on the propodeal dorsum, universal in the strenuus group, does not occur in arnoldinus.
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- arnoldinus. Technomyrmex arnoldinus Forel, 1913j: 222 (w.) ZIMBABWE. See also: Bolton, 2007a: 21.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Bolton (2007) - TL 2.6 3.2, HL 0.62 - 0.73, HW 0.56 - 0.66, SL 0.54 - 0.60, PW 0.38 - 0.46, WL 0.80 - 0.90 (7 measured). Indices: CI 86 - 90, SI 91 - 100, or 29 - 31, EPI 84 - 89, DTI 120 - 136.
Frontal carina with 3 - 4 setae: in profile always one above the torulus, one at level of anterior margin of eye and another at level of posterior margin of eye. Behind this the dorsum with a pair of setae (very rarely 2) about midway to posterior margin, and a final pair at the posterior margin. Anterior clypeal margin with a conspicuous median impression or notch, semicircular or nearly so; depth of notch is variable but it is always distinct. Eyes relatively large and conspicuous, located close to midlength and their outer margins just fail to break, or just touch, the outline of the sides in full-face view. Head weakly shining, the little sculpture that is present is weak and superficial, almost vestigial; without blanketing fine shagreenate or microreticulate scu1pture. Pronotal dorsum more or less smooth, with only traces of superficial sculpture. Mesonotum and propodeaJ dorsum more strongly sculptured, shallowly reticulate-punctate. Declivity of propodeum with fine transverse ru&Ulae at least on basal two-thirds but often over the entire surface. Number of setal paIrs on mesosoma: pronotum 2 - 4; mesonotum 2; propodeal dorsum 0; lateral margins of declivity 2 - 3, Gastral tergites 1 - 4 each with setae, the longest on the first tergite at least equal to the maximum diameter of the eye and frequently longer. First gastral tergite only feebly superficially sculptured, shiny. Pubescence on gastral tersites 1 - 4 sparse but long, reclinate to somewhat elevated. Head, mesosoma and petiole yellow to brown; gaster may be the same colour but is usually darker. Legs uniformly yellow to brown, usually slightly lighter than the mesosoma.
Bolton (2007) - Syntype workers, Zimbabwe: Bulawayo (G. Arnold) (Musee d'Histoire Naturelle Genève) [examined].
- Bolton, B. 2007b. Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker caste. Contributions of the American Entomological Institute. 35(1): 1-149.
- Forel, A. 1913k. Ameisen aus Rhodesia, Kapland usw. (Hym.) gesammelt von Herrn G. Arnold, Dr. H. Brauns und Anderen. Dtsch. Entomol. Z. 1913(Su Suppl: 203-225 (page 222, worker described)