Xymmer muticus

Known from sampling of litter and soil in rainforest and savannah habitats. Little else is know about the biology of this species.

Identification
The worker mandibles, shape of the head and general body form are most similar to Amblyopone, Prionopelta and Stigmatomma.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Central African Republic, Ghana, Ivory Coast, Nigeria.

Nomenclature

 *  muticus. Stigmatomma (Xymmer) muticum Santschi, 1914d: 311, fig. 2 (w.) NIGERIA. Combination in Xymmer: Wheeler, W.M. 1922a: 758; in Amblyopone: Brown, 1960a: 168; in Xymmer: Yoshimura & Fisher, 2012: 19.

Worker
Yoshimura & Fisher (2012) - TL 3.5 mm, including mandibles. Colour brownish-red; mandibles, antennae and legs more yellowish. Shiny; smooth with very fine but quite dense puncturation. Hairs limited to a very few around the mouth and gastral apex. Pubescence all over quite abundant but not concealing the sculpturation. Head a fifth longer than wide, a quarter more narrow behind than in front; sides slightly arcuate, near straight and posterior border distinctly concave. Blind, sometimes a rudimentary facet at the posterior third. Frontal carinae set well apart; clypeus rectangular four times wider than long. Frontal notch very narrow. Scape reaching the posterior quarter of the head. All funiculus segments wider than long. Mandibles shiny, densely punctate, narrow, length about three-quarters that of the head; external border near straight in basal four-fifths before the strongly convex apical fifth. Internal border slightly convex and with eight teeth strong and simple (rarely bifurcate) with the space between second and third bigger than between others. Thorax dorsum flat and sub-bordered. Pronotum a quarter longer than wide. Mesonotum and propodeum fused, about three times longer than wide, with almost straight sides. Propodeum dorsum more distinctly bordered behind, passing into the declivity with a sharp curve. Declivity, straight from one side to the other, convex from above to bottom in the lower third, concave basally. Petiole node a third longer than wide, sides somewhat convex, higher in front than behind. Without ventral process but with a very low simple tubercle. First segment of gaster shorter than petiole, high than long and as long as the posterior width. This species is characterized by the clypeus having no armament and being lobed.

Type Material
Yoshimura & Fisher (2012) - Lectotype worker from Nigerie S. lbadan, Nigeria, Silvestri. Det. Santchi 1913 : CASENT0217322.