Atopomyrmex mocquerysi

Strongly polymorphic arboreal ants that nest in the wood of standing trees. Atopomyrmex mocquerysi forage arboreally, frequently coming down the trunk but only rarely venturing onto the ground. Arnold (1916) points out that A. mocquerysi is usually carnivorous and, when disturbed, exudes a whitish secretion from the anal glands. Nests are made in hollow stems or rotten parts of standing timber but it is not known if the species tunnel their own galleries or take over the galleries of termites and boring beetles. Atopomyrmex mocquerysi is very widely distributed, being found in wooded and forested areas almost throughout sub-Saharan Africa. (Bolton 1981)

Identification
Bolton (1981) - differing from Atopomyrmex cryptoceroides as follows:

cryptoceroides - Sides of head behind eyes smooth and shining between widely scattered pits, not blanketed by reticulate-punctate sculpture and never with rugulae in this area; Propodeal dorsum strongly rugose, without or only with vestiges of punctate sculpture; Pronotal dorsum closely and coarsely rugose, without dense punctate ground-sculpture; Propodeal spines in dorsal view with their basal portions projecting outwards before angling backwards, the projecting portion concealing the spiracle which is not at all visible from above; Propodeal spiracle large and relatively close to the margin of the declivity below the spine; diameter of spiracle equal to or greater than the distance separating the spiracular hind margin from the edge of the declivity at its closest point.

mocquerysi - Sides of head behind eyes blanketed by dense reticulate punctate sculpture; sometimes rugulae may also occur in this area; Propodeal dorsum predominantly or entirely reticulate-punctate, if rugulae occur they are secondary to the punctuation; Pronotal dorsum usually with rugae present but with punctate ground-sculpture which is usually conspicuous and dense; Propodeal spines in dorsal view directed more or less evenly backwards, not projecting outwards basally; the spiracle (or at least its annulus) clearly visible from above; Propodeal spiracle smaller and some distance away from the margin of the declivity below the spine; diameter of spiracle less than the distance separating the spiracular hind margin from the edge of the declivity at its closest point.

Distribution based on Regional Taxon Lists
Afrotropical Region: Benin, Cameroun, Central African Republic, Democratic Republic of Congo, Ghana, Kenya, Malawi, Mozambique, Nigeria, Senegal, Sierra Leone, South Africa, Sudan, Uganda, United Republic of Tanzania, Zambia, Zimbabwe.

Nomenclature

 *  mocquerysi. Atopomyrmex mocquerysi André, 1889: 227 (w.) SENEGAL. André, 1895a: 3 (q.); Forel, 1913b: 335 (m.). Senior synonym of australis: Wheeler, W.M. 1922a: 885; of arnoldi, erigens, obscura, opaca and material of the unavailable name nigellus referred here: Bolton, 1981b: 251.
 * australis. Atopomyrmex mocquerysi var. australis Santschi, 1914e: 16 (w.) SOUTH AFRICA. Junior synonym of mocquerysi: Wheeler, W.M. 1922a: 885.
 * arnoldi. Atopomyrmex mocquerysi var. arnoldi Santschi, 1923e: 283 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of mocquerysi: Bolton, 1981b: 251.
 * obscura. Atopomyrmex mocquerysi var. obscura Santschi, 1923e: 283 (w.) IVORY COAST. Junior synonym of mocquerysi: Bolton, 1981b: 251.
 * opaca. Atopomyrmex mocquerysi st. opaca Santschi, 1923e: 283 (w.) ANGOLA. [Also described as new by Santschi, 1925h: 163.] Junior synonym of mocquerysi: Bolton, 1981b: 251.
 * erigens. Atopomyrmex mocquerysi var. erigens Santschi, 1924b: 205 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of mocquerysi: Bolton, 1981b: 251.

Worker
Bolton (1981) - Standard measurements are obviously not of great value where continuously polymorphic species are involved, as one size grades into another without any break. However, when graphs of the relationships of various dimensions are plotted a number of allometric relationships become apparent. Most easily noticeable of these are the following. The CI increases with increase in HW; the relative lengths of the scapes (SI) decrease as HW increases; the frontal carinae increase in length and strength as HW increases. The size of the eye has little or no dependence on the size of the head, the eyes of the largest workers being relatively only slightly increased in size over those of the smallest (as expressed by the ratio of ocular diameter to HW). Overall size range in the species is TL 4.0-8.7, HL 0.96-2.24, HW 0.88-2.30, CI 92-104, SL 0.70-1.22, SI 49-80, PW 0.68-1.40, At 1.34-2.50 (85 measured).

Basic characters as given under generic diagnosis, differentiation from cryptoceroides as tabulated above (see Identification section). Mandibles pitted, the surface between the pits finely and densely shagreened to finely striate. Frontal carinae increasing in length and strength with increasing worker size. In smallest workers short, ending in front of the level of the anterior margins of the eyes, forming a short and narrow laterally projecting flange on each side and only very slightly divergent. In larger workers the frontal carinae lengthening and becoming more obviously divergent, the laterally projecting flange broadening. In largest workers the carinae reaching back beyond the level of the eyes, divergent to eye level then becoming almost parallel, the laterally projecting flange very prominent throughout most or all of the length of the carinae. Antennal scrobes absent in small workers, becoming better defined with increased size; in large workers the scrobe conspicuous, narrow but quite deep and capable of accommodating the scape. Change in head shape with increased size. Maximum diameter of eye 0.18-0.36, about 0.14-0.20 x HW, the relative size of the eyes not radically increased in larger workers. Propodeal spines very variable in length, thickness and degree of curvature. In dorsal view the spines not projecting outwards in their basal portions, the propodeal spiracle or at least its annulus visible from above. In profile the propodeal spiracle some distance away from the margin of the declivity below the spine, the diameter of the spiracle less than the distance separating it from the margin of the declivity. Petiolar teeth conspicuous, varying in length and thickness. Sculpture in general increasing in intensity and frequently also in density from smaller to larger workers. Dorsum of head with scattered shallow pits, the surface between them varying from smooth or almost smooth to densely reticulate-punctate. This ground-sculpture is overlaid between the frontal carinae by fine dense longitudinal striation. As the frontal carinae increase in length so the area of striate sculpture becomes stronger and extends further back on the head. In larger specimens the space between the frontal carinae becomes strongly rugose or costate and this sculpture may reach back almost to the occipital margin. Sides of head densely reticulate-punctate everywhere. With increasing size there is a tendency for the progressive encroachment of rugulose sculpture across the reticulate-punctate surface from the front to the back of the sides. Small workers have only the punctate sculpture but as size increases rugulae appear anteriorly which gradually strengthen and spread further back on the head. Pronotal dorsum longitudinally rugose at least centrally, the rugae varying in intensity and sometimes divergent posteriorly. Ground-sculpture reticulate-punctate and usually distinct, sometimes faint and frequently with larger superimposed punctures present. Pronotal sculpture continuing onto mesonotum in smaller workers, but in larger individuals (and also in some smaller ones) the sculpture becomes reduced on the mesonotum so that only the punctate ground-sculpture is present or rugae occur but are restricted to the anterior part of the sclerite. In large workers there is usually a striking reduction in mesonotal sculpture so that most or all of the dorsum is feebly punctulate or even smooth and shining. Propodeal dorsum densely reticulate-punctate, usually without trace ofrugulose sculpture but sometimes with one or two weak rugulae present. Petiole, postpetiole and first gastral tergite finely and very densely reticulate-punctate to densely shagreened. Dorsal surfaces of body without standing hairs of any description. Colour very variable, ranging from dull yellowish brown to blackish brown but most commonly bicoloured, with head and alitrunk reddish, gaster dark brown to black. In some the head alone reddish and the rest of the body darker, in others the head and gaster dark and the alitrunk lighter.