Tetramorium parasiticum

Identification
Bolton (1980) - This is the second parasitic species known in Tetramorium (the first being microgyna of the sericeiventre-group). Its host species is Tetramorium avium, and parasiticum appears to belong to the same species-group as its host. For comparative purposes the normal female of avium is illustrated in Figs 63, 64 and the main differences between host and parasite are immediately visible by examining the figures. Other differences between them beside outline shape, are tabulated below.

T. avium female
 * Larger, HW 0.72. PW 0.70
 * Scapes relatively short, SI 94
 * Alitrunk short and broad, AL about 1.7 x PW
 * Head shorter and broader, CI 88
 * Propodeum with a pair of spines
 * Frontal carinae extending beyond level of eyes
 * Head and mesoscutum with regular sculpture
 * Clavate hairs absent

T. parasiticum female
 * Smaller, HW 0.56, PW 0.48
 * Scapes relatively long, SI 118
 * Alitrunk lomg and narrow, AL about 2.3 x PW
 * Head longer and narrower, CI 78
 * Propodeum unarmed
 * Frontal carinae ending before level of spines
 * Head and mesoscutum unsculptured except for hair-pits
 * Clavate hairs present

Distribution based on Regional Taxon Lists
Afrotropical Region: South Africa.

Nomenclature

 *  parasiticum. Tetramorium parasiticum Bolton, 1980: 281, figs. 65, 66 (q.) SOUTH AFRICA.

Queen
Holotype: TL 3.5, HL 0.72, HW 0.56, CI 78, SL 0.66, SI 118, PW 0.48, AL 1.10.

Apical tooth of mandible long and strong; mandibles smooth with scattered pits. Clypeus with anterior margin arcuate and entire, without a median notch and projecting over the basal borders of the mandibles. Median portion of clypeus more or less flat transversely in its anterior half. Longitudinally the clypeus is feebly convex between the lobes of the frontal carinae but anterior to this the clypeus passes through a curve and its anterior half is shallowly concave. Anterior half of clypeus with a strong median carina which does not reach back to the convex portion between the carinal lobes. Frontal carinae ending at level of posteriormost point of antennal foveae, without trace of antennal scrobes. Scapes long, SI > 100. Dorsum of head between eyes strongly transversely convex. Outline shape of head as in Figure. Alitrunk in profile long and low, the propodeum unarmed, shaped as in Figure, metapleural lobes low and rounded. In dorsal view the alitrunk long and narrow, AL about 2.3 x PW, the sides of the pronotum concave. Petiole in profile as shown in Figure. Note that the ventral margin is convex and keel-like and that dorsally the dorsal and posterior faces of the node have fused into a single sloping surface. Postpetiole with a strongly projecting sternal portion. In dorsal view the petiole is long and narrow, the postpetiole much broader. Head with feeble rugular sculpture in the space between the eye and the antennal foveae and between the eye and clypeus, remainder of head unsculptured except for a number of broad, shallow and widely spaced pits from which hairs arise. Alitrunk laterally with feeble sculpture on median portion of pronotum and on propodeum, rest of sides almost completely smooth. In dorsal view the propodeum rugulose and rough, the remainder of the alitrunk smooth with scattered hair-pits. Petiole, postpetiole and gaster unsculptured. Dorsal surfaces of head, propodeum and pedicel segments with short stout hairs, many or all of which are weakly clavate apically. Pronotum hairless except for a row of short clavate hairs immediately in front of the promesonotal suture. Mesothoracic dorsum with larger, simple hairs on the mesoscutum which tend to become shorter and more strongly clavate on the scutellum. First gastral tergite with subdecumbent to decumbent simple hairs. Colour uniform blackish brown. Parasitic species in nests of Tetramorium avium.

Type Material
Holotype female, South Africa: Natal, Gillitts, 35 km NW. of Durban, 500 m, 23.i.1977, native forest, rot. wood; in nest of Tetramorium avium, ser. AB 23 (W. L. & D. E. Brown).