Cataulacus impressus

Identification
This small but aberrant species is immediately recognizable by the shape of the alitrunk in profile and the presence of a transverse groove upon the occipital surface just dorsal to the foramen.

Distribution
This taxon was described from Uganda.

Nomenclature

 *  impressus. Cataulacus impressus Bolton, 1974a: 35 (w.) UGANDA.

Worker
Holotype. TL 3.7, HL 0.90, HW 0.86, CI 96, EL 0.46, OI 53, IOD 0.64, SL 0.44, SI 51, PW 0.70, AL 0.98, MTL 0.46.

Occipital crest absent, the occiput and vertex meeting in a smoothly convex curve. Occipital surface just above the foramen with a marked transverse groove or impression, behind which the remaining thin strip of the occiput juts out over the dorsal portion of the foramen itself. Occipital corners each with a single denticle and flanked internally upon the occipital margin by a larger and more conspicuous denticle. Sides of head behind eyes sparsely and minutely denticulate. Clypeal suture demarcated by a strongly impressed arc. Pronotum strongly marginate laterally, the margins sparsely equipped with small, broadly triangular denticles. Mesonotum and propodeum more weakly marginate than pronotum, denticulate, the propodeum armed with a pair of long, broad, dorsoventrally flattened spines which are nearly parallel, only slightly divergent posteriorly. In dorsal view the sides of the pronotum are parallel, the alitrunk becoming narrower at the mesonotum and again at the propodeum. In profile the posterior portion of the mesonotum curves abruptly downwards to the surface of the propodeum so that the more or less flat surfaces of the two are separated by a short but distinct step. Subpetiolar process apparently with a prominent, rounded anteroventral angle and an acute posteroventral angle which is not, however, produced into a spur. Subpostpetiolar process developed, digitiform, simple. First gastral tergite not marginate laterally.

Head with a fine rugoreticulum, the interspaces of which are finely but shallowly reticulate-punctate and shining. Dorsal alitrunk finely longitudinally rugose, the individual rugae widely separated (i.e. distance separating rugae is greater than the width of the individual rugae), the interspaces finely reticulate-punctate and shining. Cross-meshes very sparse upon the dorsum but present in places. Posterior face of petiole with a few very weak transverse rugulae, otherwise the pedicel irregularly finely rugulose and reticulate-punctate. First gastral tergite finely and quite superficially reticulate-punctate, shining.

All dorsal surfaces of head, body and appendages with numerous stout, erect, blunt hairs.

Type Material
Holotype worker, UGANDA (without further data) (MCZ, Boston).

Additional References

 * [[Media:Bolton 1974a.pdf|Bolton, B. 1974a. A revision of the Palaeotropical arboreal ant genus Cataulacus F. Smith (Hymenoptera: Formicidae). Bull. Br. Mus. (Nat. Hist.) Entomol. 30: 1-105 PDF]]