Tetramorium amatongae

Little is know about the biology of . A collection of this species was made from primary forest in Tanzania.

Identification
Bolton (1980) - When Arnold first described this form he associated it with Tetramorium setigerum, which it superficially resembles but to which it is not really related. The presence of an anterior clypeal notch and the short antennal scapes quickly exclude T. amatongae from further consideration with the allies of setigerum. In many respects amatongae approaches the camerunense-group but the structure of the petiole militates against its inclusion here. It is possible that amatongae represents the remnants of a stock basal to the camerunense-group as the petiole shape of the latter can be easily derived from the former, but this is only speculation and cannot be proved at present. The only species truly related to amatongae is Tetramorium lobulicorne, and the characters which exclude the former from placement in any other group also apply to the latter. The two are separated as follows.

Tetramorium amatongae
 * Postpetiole dorsum with strong rugulose sculpture.
 * Hairs on dorsal alitrunk and first gastral tergite long and acute, the longest exceeding the maximum diameter of the eye.
 * Base of first gastral tergite smooth.
 * Propodeal spines obviously much longer than metapleural lobes.
 * Dorsal alitrunk without punctulate groundsculpture.

Tetramorium lobulicorne
 * Postpetiole dorsum reticulate-punctate.
 * Hairs on dorsal alitrunk and first gastral tergite short, stout and blunt, the longest distinctly shorter than the maximum diameter of the eye.
 * Base of first gastral tergite shagreened or lightly densely punctulate.
 * Propodeal spines only slightly longer than metapleural lobes.
 * Dorsal alitrunk with conspicuous punctulate ground-sculpture.

Distribution based on Regional Taxon Lists
Afrotropical Region: Mozambique, United Republic of Tanzania.

Nomenclature

 *  amatongae. Tetramorium amatongae Bolton, 1980: 358, figs. 133, 137 (w.) MOZAMBIQUE.

Worker
Holotype: TL 3.9, HL 0.92, HW 0.82, CI 89, SL 0.70, SI 85, PW 0.56, AL 1.05. Paratypes (12 measured): TL 3.6-4.1, HL 0.88-0.94, HW 0.76-0.82, CI 86-89, SL 0.64-0.72, SI 83-90, PW 0.52-0.59, AL 0.98-1.08.

Mandibles longitudinally striate. Anterior clypeal margin with a median notch or impression. Frontal carinae elongate, surmounted by a low rim or crest, running back almost to the occipital margin but becoming weaker behind the level of the eyes; occipitally no stronger than the remaining sculpture. Antennal scrobes vestigial and poorly defined. Maximum diameter of eye 0.18, about 0.22 x HW and with 9-10 ommatidia in the longest row. Dorsum of alitrunk uninterrupted in profile or at most with a very slight metanotal impression. Propodeal spines elevated, long and narrow, acute apically, usually straight but sometimes very feebly curved. Metapleural lobes triangular and low, much shorter than the propodeal spines. Petiole in profile nodiform, with a long anterior peduncle. Anterior and dorsal surfaces of node meeting in a right-angle or near right-angle but the dorsal and posterior surfaces separated by a short bluntly rounded curve, not by an angle. In dorsal view the petiole node is as long as broad or slightly broader than long. Dorsum of head with sharp, spaced-out longitudinal rugulae, 8-11 present between the frontal carinae at eye level. A few weak anastomoses occur occipitally between the rugulae but no rugoreticulum is developed. Ground-sculpture on head faint, the spaces between the rugulae shining. Dorsal alitrunk predominantly longitudinally sharply rugulose, the rugulae most regular and most widely and evenly spaced on the anterior half of the pronotum. Behind this the rugulae are less regular and a few weak cross-meshes are developed. Ground-sculpture on the alitrunk vestigial. Petiole and postpetiole finely but sharply rugulose dorsally, the latter segment predominantly longitudinally so. First gastral tergite unsculptured except for hair-pits. All dorsal surfaces of head and body with numerous elongate, fine acute hairs, the longest of those on the alitrunk obviously much longer than the maximum diameter of the eye. Middle and hind tibiae with decumbent to appressed short hairs. Colour uniform mid-brown.

Paratypes: As holotype but maximum diameter of eye 0.17-0.18, about 0.22-0.24 x HW.

Type Material
Holotype worker, Mozambique: Amatongas Forest, 13.ii.1917 (G. Arnold). Paratypes. 12 workers with same data as holotype (BMNH; ; ; ).

References based on Global Ant Biodiversity Informatics

 * IZIKO South Africa Museum Collection