Calyptomyrmex Emery

Eguchi, K., Viet, B. T. & Yamane, S., 2011, Generic synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), Part I - Myrmicinae and Pseudomyrmicinae., Zootaxa 2878, pp. 1-61 : 12-13

Calyptomyrmex Emery , 1887

Taxonomy. The genus Calyptomyrmex is assigned to the tribe Stenammini (Bolton 2003). The Oriental species were revised by Baroni Urbani (1975) and the Ethiopian species by Bolton (1981). Workers of Vietnamese species have the following features.

Worker monomorphic; frontal lobe strongly expanded and overhanging anterolateral margin of clypeus; frontal carina extremely strongly developed horizontally, in full-face view overhanging antennal scrobe; antennal scrobe extremely deep, bounded above by frontal carina and below by a ridge running above eye, capable of accommodating whole antenna; median portion of clypeus behind anterior margin vertical or nearly vertical, terminating in a projecting biramous appendage (clypeal fork); clypeal fork projecting anteriad over mandibles and partially concealing them in full-face view; mandible triangular, with distinct apical tooth and single preapical tooth followed by several teeth or denticles; antenna 12-segmented, with 3-segmented club; scape curved, somewhat flattened, strongly widened distally, with a narrow projecting lamella on the leading edge of the widened part; eye present but small; mesosoma roundly convex dorsally; promesonotal suture absent dorsally; metanotal groove indistinct or shallowly impressed dorsally; dorsum of propodeum declining posteriorly; propodeal spiracle located very close to or at posterolateral margin of propodeum; propodeal spine triangular; propodeal lobe well developed; petiole pedunculate anteriorly and with a large node; subpetiolar process absent; postpetiole shorter than high; dorsal surfaces of body with short, broad and blunt hairs.

The worker of the Vietnamese species is somewhat similar to that of Mayriella , but in the latter the antenna is 10-segmented, the eye is large and elongate, and the dorsa of the head and mesosoma bear sparse, long, standing hairs.

Vietnamese species. Only one species has been described from Vietnam: rectopilosus Dlussky & Radchenko [= sp. eg-1] (type locality: Bai Tu Long; other localities: Ba Be, Chua Yen Tu, Phu Quoc, Pu Mat, Tay Yen Tu, Van Ban).

Bionomics. Calyptomyrmex rectopilosus nests in rotting twigs and wood fragments on the floor of well-developed forests. Colonies are usually small, consisting of dozens of workers.