Agraulomyrmex meridionalis

The only published account of the biology of Agraulomyrmex meridionalis is provided in Prins' (1983) description of the genus and its two known species. "In 1969 surveys of ants present in citrus orchards were conducted throughout South Africa. During the cooler winter months and early spring one sample of small, brownish hypogaeic ants was collected among some citrus trees in the veld near Velddrif, a small fishing village about 200 km north-west of Cape Town. As these ants looked very much like Technomyrmex albipes, which shared the same habitat, they were noted as such in the collection records. This same species of ant was also at the time observed in a small citrus orchard near Citrusdal, about 60 km north-east of Velddrif. In this case they were tending the aphid Hyadaphis coriandri (Das) on warm days, about 4 to 7 cm above ground level on the low-growing weeds. They were, however, never observed during the summer and autumn months.

Identification
Larger than Agraulomyrmex wilsoni and darker in color. The generic diagnosis for this group (Prins 1983), with just these two species - Small ants with ten-segmented antennae, flagella incrassate towards apices without distinct club; first and last segments of flagella longer than wide, the remaining segments as long as or wider than long. Mandibles triangular with four to six teeth; frontal carinae short, antenna! fossae situated close to posterior border of clypeus. Eyes large, placed in front of middle of sides of head; ocelli absent. Maxillary palpi five- to six-segmented, labial palp three- to foursegmented. Labrum bilobed, widely and shallowly emarginate in middle. Frontal area clearly indicated.

Alitrunk with promesonotal and mesonotal-propodeal sutures well developed, mesometanotal suture absent; propodeum rounded from front to back, unarmed. Petiole with very small or rudimentary scale overhung by base of abdomen. Legs moderately long.

Although the ten-segmented antennae point to a myrmelachistine relationship, these ants share characters with the plagiolepidines, viz. the absence of a distinct antennal club, the structure and form of the alitrunk (the absence of a distinct metanotum as in certain members such as the genus Acropyga), as well as the structure of the asepalous proventriculus. The new genus is therefore included in the tribe Plagiolepidini.

Workers of these ants bear a close resemblance to those of the genus Acropyga (Prins 1982); however, they are much smaller and darker in colour, and the eyes are much larger. In members of Acropyga the eyes are very small, consisting of only a few facets. The petiolar scale is also much more reduced than in Acropyga.

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

Nomenclature

 *  meridionalis. Agraulomyrmex meridionalis Prins, 1983: 2, fig. 1 (w.) SOUTH AFRICA.

Worker
Specimens collected at Velddrif from which the type material was selected: TL 2,10-2,20 mm; L0,90-l,O mm; HL 0,48-0,52 mm; ED 0,26 mm; CL 0,08-0,10 mm; FL 0,40-0,42 mm; SL 0,32-0,36 mm; WL 0,48-0,50 mm; MFL 0,28-0,30 mm; HFL 0,32-0,36 mm; PL 0,10 mm; CI 76,9-79,2; FI 61,9-65,0; SI 84,2-90,0; CLI 320,0-355,6; TI 58,0-58,3; PI 100,0; HFI 66,7-72,0.

Dark brown, tarsi and mandibles paler. Smooth and shiny all over, especially declivity o! propodeum and petiole. Finely sculptured with piliferous punctures. Pubescence fairly long, decumbent and yellowish, dense all over except on petiole and declivity. Pilosity yellowish, long, evident only on mandibles, clypeus, petiole, and apical margins of abdominal segments.

Head quadrate in dorsal view, about one-fifth to one-sixth longer than wide, and about one-third wider than pronotum, sides feebly convex, hind margin almost straight. Clypeus convex in middle, not carinate, its anterior margin arcuate as in the genus Acropyga. Scapes about two-thirds as long as head (excluding mandibles) and reaching hind margin; flagellum about two-fifths longer than scape, first segment as long as the second and third taken together, apical one slightly longer than three preceding segments taken together; rest as wide as, or wider than, long. Eyes large, oval, occupying nearly one-fourth of the length of head (dorsal view-mandibles excluded), and situated in front of middle of sides. Mandibles shiny, with few large, oval punctures, each bearing erect or semi-erect seta, and with five to six alternate large and small teeth. Maxillary palp six-segmented, labial palp four-segmented.

Alitrunk similar to that of the genus Acropyga, slightly more than three-eighths longer than wide over pronotum; seen in profile propodeum is on lower level than promesonotum, declivity almost flat and longer than dorsum of propodeum. Scale of petiole rudimentary, inclined forward and about as long as wide and slightly higher than long; seen from behind almost as wide above as below, dorsum feebly convex.

Legs moderately long. Abdomen oval in dorsal view. Acidopore on conical projection of hypopygium, orifice surrounded by fringe of hairs. Specimens which do not form part of the type material and which were collected at Citrusdal have the following representative measurements:

TL 2,0-2,20 mm; L 0,94-1,0 mm; HL 0,44-0,48 mm; ED 0,22-0,26 mm; CL 0,09-0,10 mm; FL 0,34-0,39 mm; SL 0,32-0,34 mm; WL 0,46-0,52 mm; MFL 0,26-0,28 mm; HFL 0,32-0,34 mm; PL 0,10-0,11 mm; CI 77,3-83,3; FI 64,1- 68,4; SI 85,0-94,1; CLI 320,0-355,6; TI 53,8-56,5; PI 80,0-90,0; HFI 65,3-69,61.

In most of the specimens examined the head is somewhat shorter than the alitrunk and the scale of the petiole slightly longer than wide, otherwise similar in all respects to the Velddrif specimens.

Type Material
Holotype. 1 worker, Velddrif, Cape Province (32°47'S l8°10'E), collected by A. J. Prins 7 July 1959, South African Museum specimen. Paratypes. 4 workers, as above, South African Museum specimens.

Etymology
The name meridianalis is derived from the Latin word meridional-, which refers to the southerly distribution of this species.

References based on Global Ant Biodiversity Informatics

 * Prins A. J. 1983. A new ant genus from southern Africa (Hymenoptera, Formicidae). Annals of the South African Museum 94: 1-11.