Diacamma holzschuhi

Identification
D i a g n o s i s : Relatively small species (TL 10.5–11.7mm). Trunk black, without metallic shimmer. Mandibles and legs dark brown to black. Long setae abundant; fine pilosity sparse. Trunk coarsely striate from genae to gaster tergite 1. Head (Fig.42) short, sides posteriorly of eye strongly convex. Posterior of head longitudinally striate until narrowly truncated hind margin; narrow margin ventrally terminating in short, acute teeth (Fig.40). Eyes moderately large. Clypeus (Fig.42) entirely punctured, apex acute. Mandible with some strong punctures and with fine striation, in some specimens obliterate. Pronotum (Fig.41) concentrically striate, but with some short transverse rugae in centre. Striation on propodeum oblique (Fig.40). Petiole (Figs.40, 41) very stout, its teeth moderately long; subpetiolar process shallowly concave between acute anterior and posterior corners. Gaster tergite 1 (Figs.40, 41) with semi-circular striation.

Distribution based on Regional Taxon Lists
Oriental Region: Laos.

Nomenclature

 *  holzschuhi. Diacamma holzschuhi Laciny, Pal & Zettel, 2015: 115, figs. 40-43 (w.) LAOS.

Description
Structures: Head (Fig.42) relatively short; sides strongly convex behind moderately large eyes. Coarse rugae present from genae to gaster tergite 1. Posterior of eyes, longitudinal rugae reaching very narrow occipital margin. On ventral side of head occipital margin ending in a small, but sharp tooth (Fig.40). Clypeus (Fig.42) entirely punctured, but shiny, strongly protruded into an approximately rectangular, sharp apex. Mandible with some strong punctures and with fine striation, in some specimens obliterate. Pronotum (Fig.41) concentrically striate, with some short, transverse rugae in centre. Rugae on mesosoma sides oblique (Fig.40). Posterior face of propodeum separated from sides by distinct carinae. Petiole (Figs.40, 41) very stout, its teeth moderately long, with pronounced concavity between them; subpetiolar process with shallowly concave, densely pilose outline, in ventral aspect with paired medial carinae and short lateral carinae anteriorly, anterior and posterior corners acute. Gaster tergite 1 (Figs. 40, 41) with coarse, transverse-concentric, semi-elliptical rugae; along posterior margin densely punctured. Gaster tergite 2 (Figs.40, 41) shiny, with very fine microsculpture that is reduced on disc in a few specimens; with delicate traces of a short longitudinal striation on sides of disc in two specimens. Figs.42–43: Diacamma holzschuhi sp.n., holotype worker. (42) Head, frontal. (43) Labels. Pilosity (Fig.40): Trunk and legs with numerous, long setae; standing setae on scape slightly shorter. Short appressed pilosity weakly developed, but denser on clypeus, mesonotum, meso- and metapleura, dorsal face of propodeum, posterior margins of pronotum and gaster tergite 1, and the other gastral tergites. Colour (Fig. 40): Trunk black, without metallic shimmer, but shiny. Very narrow hindmargins of gaster tergites and sternites yellowish brown. Mandibles and legs (except for black fore coxae) dark reddish brown or blackish.


 * Etymology: Kindly dedicated to Dr. Carolus Holzschuh who provided the specimens.