Myrmicocrypta unidentata, Neal A. Weber, University of North Dakota, 1936

Neal A. Weber, University of North Dakota, 1936, The biology of the fungus-growing ants. Part. I. New forms. 1, Revista de Entomologia 7, pp. 378-409 : 384-385

Myrmicocrypta unidentata , sp. nov.

Worker: Length 1.8 mm. - Head, excluding mandibles, 1.1 times as long as wide, occipital margin broadly convex, with rounded and shallow medial impression, sides sub-parallel, feebly convex in front of and behind eyes, anterior clypeal margin convex, posterior sides raised as acute teeth. Eyes small, convex, situated in middle of sides. Frontal lobes moderately large, reflected. Frontal region shallowly concave in middle, not distinctly marginate. Cutting margin of mandibles without distinct teeth, apical tooth well developed. Antennal scapes of moderate proportions, inflated and slightly curved distally, exceeding posterior margin by a distance equal to less than their distal diameter. Joints 2-9 of funiculus about as broad as long, terminal joint equal in length to joints 4-9 taken together.

Pronotum lacking the anterior and dorso-lateral pair of tubercles, sides with low carinae ending dorsally where the tubercles are in other species. Mesonotum, in profile, high arid convex, with three pairs of blunt tubercles of which the anterior is largest; from the posterior tubercle the mesonotum drops abruptly to the mesoepinotal impression except for a single stout and pointed tubercle on this declivous surface which is larger than any preceding. Basal surface of epinotum carinate on margins and produced behind as small but distinct teeth.

Peduncle of petiole shorter than node, the latter rising smoothly and convexly to a posteriorly descending dorsal surface. Postpetiole in profile with evenly convex dorsal and ventral surfaces, slightly shorter in length than petiole; from above trapezoidal, anterior and posterior margins parallel, feebly impressed postero-medially. First gastric segment slightly longer than wide, anterior and posterior margins straight. Legs of moderate length.

Opaque finely shagreened, mandibles finely striate. - Hairs of head numerous, narrow squamate; sparse on thorax, being confined to. projections, squamate; sparse on pedicel and gaster, squamate; more numerous on antennal scapes and legs but not greatly obscuring integument, narrow squamate. Pale ferruginous, darker on head, mandibles brown.

Described from one worker taken by myself August 23, 1935, in virgin greenheart (Nectandra Rodei Schomb.) forest near the Forest Settlement, Mazaruni River, British Guiana.

This species is noteworthy in small size, single large tooth or tubercle on declivous surface of mesonotum above the mesoepinotal impression, reduced spinulation and sparse pilosity of thorax. It cannot belong to M. elisabethae n. sp. here described because of the very different frontal lobes, pronotal spines, and postpetiole.