Pristomyrmex fossulatus (Forel)

Bolton, B., 1981, A revision of six minor genera of Myrmicinae (Hymenoptera: Formicidae) in the Ethiopian zoogeographical region., Bulletin of the British Museum (Natural History) Entomology 43, pp. 245-307 : 285-286

Pristomyrmex fossulatus (Forel)

Tetramorium (Xiphomyrmex) fossulatum Forel , 1910 a: 428. Syntype workers, South Africa: Natal, Will

Broak [Willbrook] (Wroughton) (MHN, Geneva) [examined]. Pristomyrmex fossulatus (Forel) Santschi, 1916: 51.

Workers. TL 2.7 - 3.2, HL 0.65 - 0.72, HW 0.62 - 0.70, CI 95 - 97, SL 0.54 - 0.60, SI 82 - 90, PW 0.46 - 0.52, AL 0.68 - 0.70 (3 measured).

Mandibles with vestiges of striate sculpture basally but mostly smooth with scattered small pits. Apical (masticatory) margin of mandible with strongly developed apical and preapical teeth followed by a diastema and a basal tooth which may be truncated. Clypeus with a sharp median longitudinal carina. Median portion of clypeus with the anterior margin shallowly concave and armed with denticles; a median denticle and 2 - 3 others on each side. Frontal carinae present and distinct, running back to the level of the posterior margins of the eyes and forming the dorsal margins of the narrow, short antennal scrobes. Lower margin of scrobe delimited by a longitudinal ruga above the eye, which runs back from the antennal fossa approximately to the midlength of the eye. Eyes large, maximum diameter c. 018, about 0.26 - 0.29 x HW, with 8 - 10 ommatidia in the longest row. With the head in full-face view the side convergent behind the eyes and rounding into the occipital margin which is straight to very feebly and shallowly concave. With the alitrunk in profile the pronotum only with a low, broad, blunt tubercle, without the teeth or spines frequently encountered in this genus; in dorsal view the tubercles appear as low, bluntly rounded angles. Propodeum with a pair of strong spines which are distinctly longer than their basal width. Metapleural lobes narrow and strongly prominent. Petiole in profile wedge-shaped, strongly tapering dorsally and with the apex of the triangular shape blunted. In dorsal view the petiole node broader than long. Subpetiolar process a long narrow low flange. Dorsum of head between frontal carinae with scattered large shallow foveolate punctures. Similar punctures also present on the sides of the head but generally less conspicuous. Dorsal alitrunk also with foveolate punctures but here they are very sparse, widely separated, very shallow and inconspicuous. Apart from these punctate areas the entirety of the head and body smooth and shining, with pedicel segments and gaster completely unsculptured. Hairs present on mouthparts and gastral apex, otherwise the dorsum only with 4 - 5 pairs on the head behind the level of the antennal insertions, following the line of the frontal carinae; alitrunk with a single pair, on the mesonotum; petiole with 0 - 1 and postpetiole with 1 - 2 pairs dorsally; first gastral tergite hairless. Colour glossy light brown.

Known only from the type-series collected in South Africa, fossulatus is related to africanus and orbiceps . It separates easily from the former as its eyes are much larger (0.26 - 0.29 x HW as opposed to 0.12 - 0.15 x HW) and its alitrunk lacks the sharp pronotal teeth or broad spines seen in africanus . The eye size of orbiceps is closer to that of fossulatus (but still smaller); orbiceps lacks the foveolate cephalic sculpture of fossulatus and also lacks the very distinctively shaped petiole node seen in the latter.