Meranoplus nanus Ern. Andre subspecies soriculus, Wheeler, W. M., 1922

Wheeler, W. M., 1922, The ants collected by the American Museum Congo Expedition., Bulletin of the American Museum of Natural History 45, pp. 39-269 : 184-187

Meranoplus nanus Ern. Andre subspecies soriculus , new subspecies

Text Figure 45

Worker.- Length 1.8 to 2 mm.

Head subtrapezoidal, as broad as long, rather convex and rounded above, truncated behind. Mandibles with oblique, 4-toothed apical borders. Clypeus rather flat, with a short median carina posteriorly. Frontal area transverse, crescentic. Scrobes deep, extending to the posterior corners of the head. Eyes rather large, convex. Antenna- robust; club distinctly longer than the remainder of the funiculus. Pro- and mesonotum transversely rectangular, slightly broader than the head without the eyes, about one and one-half times as broad as long (somewhat too long in the figure), with sharply dentate anterior corners, the sides distinctly emarginate at the mesoepinotal suture, which is straight and very distinct. Mesonotum roundedon the sides and narrowed to the posterior border, which bears four short, blunt, flattened teeth, the median pair heing smaller and more approximated. Epinotum vertical, unarmed, somewhat concave in the middle, with a longitudinal welt on each side representing the spines. Petiole cuneate in profile, the node much compressed anteroposteriorly, much higher than the length of the segment, narrowed and bluntly pointed above, higher than the postpetiolar node, which has a similar shape but is less compressed above and with broader, transverse border. Gaster large, convex above, pointed posteriorly, its anterior border excised in the middle. Legs rather stout.

Shining; mandibles opaque, finely and indistinctly striatopunctate. Clypeus and upper surface of head longitudinally but not strongly rugulose, with indistinctly punctate-reticulate interrugal spaces. Cheeks longitudinally rugose. Truncated posterior surface of head rather regularly reticulate rugose. Pro- and mesonotum with similar sculpture but the rugae are feebler, so that the surface is more shining; sides of thorax and epinotum nearly smooth, as are also the petiole and postpetiole. First gastric segment evenly covered with shallow punctures interspersed with extremely minute punctures.

Hairs white, delicate, soft, and abundant, forming a uniform erect fleece on the upper surface of the body, more oblique on the appendages, on the legs interspersed with a few exceptionally long hairs.

Brown; upper surface of head and first gastric segment, except at the base, dark brown; mandibles, except the teeth, legs, and antennae brownish yellow.

Female.- Length 4.5 to 4.8 mm.

Head like that of the worker. Thorax broader than the head, about one and three-fourths times as long as broad; broadest through the pronotum, the sides of which are somewhat swollen, but have blunt, though distinct, teeth. Mesonotum somewhat broader than long. Petiole and postpetiole much as in the worker, but the postpetiolar node is thicker above in profile.

Sculpture like that of the worker, but the mandibles coarsely striate and the sides of the thorax coarsely and irregularly reticulate rugose.

Hairs yellow, coarser, and shorter, especially on the gaster, than in the worker.

Color like that of the worker, but the mesonotum with three large, poorly defined, dark brown patches. Wings yellowish hyaline, with pale yellow veins and pterostigma.

Male.- Length 2.5 mm.

Head, including the eyes, as broad as long, very convex behind. Eyes and ocelli large and convex; cheeks very short. Clypeus convex in the middle. Antennal scapes scarcely more than twice as long as broad; first funicular joint globose, second somewhat longer than the scape but distinctly more slender than the third joint. Thorax short, broader than the head including the eyes. Mesonotum convex, with distinct Mayrian furrows. Epinotum like that of the worker, but more sloping. Petiole longer than high or broad, the node low, angular in profile, with subequal anterior and posterior slopes, the former straight, the latter slightly concave. Postpetiole as long as high, somewhat depressed above, transverse, broader than the petiole.

Clypeus smooth and shining in the middle. Head subopaque, reticulate-rugulose. Pronotum and epinotum indistinctly punctate-rugulose, subopaque; mesopleurae smooth and shining; mesonotum and scutellum less smooth but shining, indistinctly punctate. Petiole longitudinally rugulose-punctate; postpetiole smoother. Gaster as in the worker but the large punctures are less distinct.

Pilosity much as in the female, but the hairs on the body are even less even and on the legs are shorter and more appressed.

Colored like the worker, but the antennae and legs are yellow. The veins and pterostigma of the wings are distinctly paler than in the female.

Described from numerous workers, five females, and six males taken at Avakubi (type locality) and a number of workers from Medje (Lang and Chapin). According to Mr. Lang, these ants "build small crater nests in the plantations. One crater was one and one-half inches high and four inches in diameter. The whole nest, three inches wide, extended beneath the surface to a depth of only six inches. The workers move very slowly. The native name is 'tungangele.' Eight workers from Medje were taken from the stomach of a toad (Bufo funereus).

I have described this form at length because it belongs to nanus Ern . Andre and is very closely related to Forel's subspecies nanior and its variety Jciboshanus and to inermis Emery. The last I regard as a subspecies of Andre's species. All of these are known only from the worker. M. nanus measures 2.75 to 3.25 mm. and has two small, acute, spiniform teeth on the epinotum. The subspecies nanior, though of the same size as soriculus (1.9 mm.), is described as having the promesonotum one and three-fourths times as broad as long, the variety Jciboshanus as being as large as the typical nanus , and inermis has the posterolateral corners of the mesonotum rectangular and, judging from Emery's figure, lacks the mesoepinotal suture. The various forms mentioned are from widely separated localities, nanus from Gaboon, inermis from Transvaal and Eritrea, nanior and kiboshanus from East Africa.