Cataulacus F. Smith

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 : 13-14

Cataulacus F. Smith , 1853

Taxonomy. The genus is assigned to the tribe Cataulacini (Bolton 2003). The genus was revised by Bolton (1974, 1982). The worker of the single Vietnamese species ( C. granulatus ) has the following features.

Worker monomorphic; head posteroventrally with an acute angle; frontal lobe and frontal carina extremely developed horizontally; frontal carina touching the ventral margin of eye and reaching to the posterolateral corner of head, and overhanging sides of head; antennal scrobe extremely deep, running below eye, capable of accommodating whole antenna; clypeus with anterolateral corners forming triangular points; posteromedian portion of clypeus widely inserted between frontal lobes; mandible small, triangular, with apical tooth, single preapical tooth and a small blunt denticle followed by a long edentate or bluntly crenulate edge which ends at the basal angle; antenna 11-segmented, with 3-segmented club; scape weakly curved, strongly widened distally and somewhat flattened with a very narrow lamella on the leading edge; eye large, located dorsolaterally behind midlength of sides of head; mesosoma in lateral view flattened dorsally; promesonotum marginate, anterodorsally with a sharp edge and dorsolaterally with a dentate edge; promesonotal suture absent dorsally; katepisternum anteriorly with an anterolaterally directed, triangular projection; metanotal groove inconspicuous or almost absent dorsally but conspicuous laterally; propodeal spine well developed as a posterolateral projecting horn; propodeal lobe well developed, blunt-triangular; petiole in lateral view somewhat globular or cuboidal, without distinct anterior peduncle, with distinct subpetiolar process; postpetiole shorter than height, with distinct anteroventral angle; first gastral tergite greatly expanded, comprising whole of gastral dorsum in dorsal view; remaining gastral segments very small, visible only apically and apicoventrally; body strongly sclerotized and sculptured, bearing short, broad and blunt hairs.

Cataulacus is easily distinguished from other myrmicine genera known from Vietnam by antennal scrobe running below eye, frontal lobe and frontal carina extremely developed horizontally, and first gastral tergite greatly expanded, comprising whole of gastral dorsum in dorsal view.

Vietnamese species. One species is known from Vietnam: granulatus Latreille [= sp. eg-1] (BaVi, Cuc Phuong, Nui Chua, My Yen, Tam Dao, Tay Yen Tu, Van Ban).

Bionomics. Cataulacus granulatus nests in hollows within living and dead twigs of trees, and workers forage on vegetation.