Tetramorium elidisum

Identification
Bolton (1980) - Amongst the five known species of the dumezi-complex, characterized by their smooth mandibles, entire clypeal margins and short sparse pilosity, T. elidisum is isolated by its possession of short erect hairs on the scapes, lack of pilosity on the legs, and very densely sculptured first gastral tergite. Of its close relatives, Tetramorium isipingense and Tetramorium candidum both have erect or suberect tibial pubescence and have standing pubescence on the leading edges of the scapes, not strong hairs such as occur on the dorsal alitrunk. Tetramorium dumezi and Tetramorium pialtum both have the gaster unsculptured and also lack strong hairs on the scapes. The swollen mesonotum mentioned in the description may be normal for the species but may equally well represent a pathological condition. As only one specimen is presently known it is impossible to say which is true, and for this reason the condition of the mesonotum has not been used as a key character. However, if the shape of the mesonotum should turn out to be usual in the species then that one character alone will isolate T. elidisum, as no other Tetramorium are known which have it swollen and saddle-shaped.

Distribution based on Regional Taxon Lists
Afrotropical Region: Ghana.

Nomenclature

 *  elidisum. Tetramorium elidisum Bolton, 1980: 346, fig. 125 (w.) GHANA.

Worker
Holotype: TL 3.4, HL 0.78, HW 0.66, CI 85, SL 0.50, SI 76, PW 0.54, AL 1.02.

Mandibles smooth and shining with scattered small pits. Anterior clypeal margin entire, without trace of a median notch. Clypeus with a median carina and one or two weak lateral carinae, widely separated from the median. Frontal carinae stronger than any of the cephalic sculpture, reaching back behind the level of the posterior margins of the eyes but becoming finer and weaker on the occiput. Maximum diameter of eye 0.18, about 0.27 x HW. Head in full-face view roughly rectangular, the sides more or less straight and approximately parallel, not evenly shallowly convex. Alitrunk with mesonotum swollen (see discussion below), in dorsal view roughly circular and delimited by finely incised lines in front and behind. In profile the mesonotum saddle-shaped, shallowly convex both anteriorly where it meets the pronotum and posteriorly where it meets the propodeum, but shallowly concave centrally. Propodeum armed with a pair of short triangular teeth which are about as long as their basal width, acute apically. Metapleural lobes triangular, distinctly broader than the propodeal teeth and slightly longer. Petiole in profile with dorsal length less than height of tergal portion of node; in dorsal view the node slightly broader than long. Dorsum of head weakly longitudinally rugulose, without cross-meshes and without an occipital reticulum. Ground-sculpture vestigial, at most a very faint superficial granulation. Pronotal dorsum with sparse weak longitudinal rugulae and a very faintly punctulate ground-sculpture. Mesonotum with ground-sculpture almost effaced and rugulose sculpture absent except for 3-4 extremely feeble vestiges which run transversely on the posterior half. Propodeal dorsum finely and densely punctulate-granular. Petiole and postpetiole dorsally with ground-sculpture almost completely effaced and with a few very fine weak rugulae. First gastral tergite everywhere finely and very densely reticulate-punctulate, stronger basally than apically. All dorsal surfaces of head and body densely clothed with short erect blunt stubbly hairs, the longest of which scarcely exceed the length of the small propodeal teeth. Leading edges of antennal scapes with numerous short stubbly erect hairs as on rest of body, but such hairs absent from the tibiae where only very sparse appressed minute pubescence is present. Colour uniform mid-brown, the appendages lighter.

Type Material
Holotype worker, Ghana: Aburi, 13.vii.1969 (P. Room).