Tetramorium kieti

Holotype collection details: worker from Vietnam forest, approximately 250 m of altitude, surface litter, formaline pitfall.

Identification
Roncin (2002) - A member of the Tetramorium scabrosum-species group. Tetramorium kraepelini is similar to Tetramorium kieti by its overall sculpture, proportions of the head, weakness of the posterior part of antennal scrobes, pilosity of scapes and hind tibiae, and moderate development of gastral tubercles, but differs by its size, the shape and sculpture of the petiole, the width of the basis of the propodial spines, and the sculpture of the basis of the first gastral tergite. Tetramorium kieti is close to Tetramorium mixtum with a very similar shape of the mesosoma and petiole in lateral view. However mixtum has a stronger concavity and more developed gastral hams on the anterior part of the first gastral tergite, a longer petiole in dorsal view, and a larger body size.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam.

Nomenclature

 *  kieti. Tetramorium kieti Roncin, 2002: 285, figs. 2, 4, 6 (w.) VIETNAM.

Worker
Holotype. TL 2.1, HL 0.544, HW+E 0.517, HW 0.485, CI 89, SL 0.392, SI 81, EL 0.118, PrW 0.362, ML 0.624, DPW 0.148, DPpW 0.219.

Head slightly longer than wide with feebly concave posterior margin in full face view; Sides weakly convex, and head width slightly decreasing from eyes to anterior clypeus margin. Mandibles striate with seven teeth, the two first distinctly stronger and the third, and the last one situated at the basal angle of mandibles, more developed than the three intercalary ones. Second tooth closer to the first than to the third one.

Anterior clypeal margin entire, moderately and regularly convex. Clypeus with three main longitudinal rugae. Anterior clypeus margin with a small horizontal rim below the anterior declivity bordering the basal margin of the mandibles when closed. Frontal carinae extending back almost to occipital corners, but behind level of eyes, becoming weak and no more strongly developed than cephalic rugae. Eyes slightly situated in front of the middle of sides of head, their maximum length 0.118 mm, about 0.24 x HW. Dorsal head sculpture between frontal carinae longitudinally rugulose, the rugae being slightly sinuous, and with some cross-meshes, more numerous near frontal carina. Rugoreticulations on posterior 1/5 of head, from the level of the posterior limit of the scrobes in full face view. This rugoreticulum also covers lateral and ventral parts of head from the lower margins of scrobes, and from mandibular insertions to occiput. Posteromedioventrally this sculpture is reduced. Spaces between frontal rugae and between the wrinkles of the coarse rugoreticulation on head and mesosoma filled with small reticulate-puncturations. Scrobes not really delimited by a margin posteriorly and laterally.

Dorsal surface of scapes with one to five erect hairs and with decumbent pubescence.

Mesosoma without any trace of dorsal sutures. its dorsum flat in profile, and with a feeble concavity between mesonotum and propodeum. Pronotal humeri angulate in dorsal view. Propodeal lobes well developed, acute, nearly as long as the propodeal spines and with dorsal and ventral outlines concave in lateral view. Propodeal spines acute. Straight to barely upcurved at their extremities, divergent in dorsal view.

Node of petiole in profile with tergal portion higher than long, roughly rectangular, with almost parallel rectilinear anterior and posterior faces and an evenly convex dorsum which meets each face in blunty right angles. In dorsal view the node is rounded and slightly longer than wide.

Petiole and postpetiole with fine superficial rugoreticulations. In dorsal view, petiolar node as wide as long or hardly longer than wide. Postpetiole transverse, wider than long, with blunt anterolateral angles and posterolateral margin progressively curved. Dorsal face of the tibia III with a few suberect hairs and with shorter semidecumbent hairs.

Base of first gastral tergite concave. widely connected with postpetiole. Anterolateral parts of first tergite gaster forming blunt tubercles or teeth antenor to the level of medioanterior margin of gaster in dorsal view. Posterior visible part of the abdominal pretergite IV with a transverse groove armored with short longitudinal costae. Gaster fairly shining but with. superficial fine reticulation (visible in alcohol under high magnification and saturated light reflection), and with basal one-sixth of the first gastral tergite with longitudinal rugulae. Lamelliform appendage of the sting projecting at an angle from the sting.

All dorsal surfaces of the body with erect stout hairs, the longer of them, situated on back of head, mesosome and gaster reaching 0.080 mm except one or two pairs on pronotum near neck shield of approximately 0.100 mm length.

Color light brown, slightly darker than Tetramorium seneb and Tetramorium securis.

TL 2.2, HL 0.556, HW+E 0.523, HW 0.481, CI 86, SL 0.405, SI 84, EL 0.118, PrW 0.369, ML 0.628, DPW 0.148, DPpW 0.207.

Type Material
The holotypes of the new species are deposited in the Museum Natwnal d'Histoire Naturelle de Paris and the paratypes in the author's collection.

Holotype worker, Vietnam: Kien Giang Province: Han Chong. Nui Binh Tri, litter in secondary forest. 19.i.2000, Berlese extraction of 1000 cm3 of litter (VIET 861), L. Deharveng, A. Bedos coll.

Etymology
I have the pleasure to dedicate this species to Professor Le Cong Kiet, head of the laboratory of botany and ecology at Ho Chi Minh-City University, who organized the field trips to Hon Chong and Nam Cat Tien.

References based on Global Ant Biodiversity Informatics

 * Roncin E. 2002. Two new Tetramorium species (Hymenoptera: Formicidae) from Vietnam with a discussion of the mixtum, tonganum, and scabrosum groups. Sociobiology 40: 281-292.