Proceratium Roger, 1863

Eguchi, Katsuyuki, Viet, Bui Tuan & Yamane, Seiki, 2014, Generic Synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), Part II — Cerapachyinae, Aenictinae, Dorylinae, Leptanillinae, Amblyoponinae, Ponerinae, Ectatomminae and Proceratiinae, Zootaxa 3860 (1), pp. 1-46 : 43

Proceratium Roger, 1863

Taxonomy. The genus Proceratium was recently revised by Baroni Urbani and Andrade (2003) and is assigned to the tribe Proceratiini together with Discothyrea and the fossil genus Bradoponera ( Bolton 2003) .

Morphology. Workers of Vietnamese species have the following features (see also Baroni Urbani and Andrade 2003):

Worker monomorphic; head in full-face view usually rounded; frontal lobes small and suberect, narrowly separated by posteromedian portion of clypeus; antennal socket in full-face view mostly to entirely exposed, located a little in front of line across mandibular bases; antennal scrobe absent; anteromedian portion of clypeus often convex; mandible subtriangular; apical tooth followed by several distinct teeth or serrate margin; antenna 12- segmented; eye vestigial (consisting of one or several ommatidia); mesosoma in lateral view relatively short and high; promesonotal suture and metanotal groove absent dorsally; posterolateral corner of propodeal dorsum simply angulate or with a spine; posterior slope of propodeum often margined laterally with a carina; propodeal lobe very low to well-developed; orifice of propodeal spiracle round; petiole variable in shape; subpetiolar process usually present, but variable in size and shape; abdominal segment III shorter than IV, sometimes much reduced in size (often mentioned as “postpetiole”); abdominal sternite III with a U-shaped anteroventral ridge below helcium, or a low flange beneath helcium; abdominal segment IV strongly down-curved; its sternite much smaller than tergite, in lateral view somewhat triangular in shape; sting well developed.

Differentiation. The worker of Proceratium is in general appearance similar to that of Discothyrea , but in the latter the mandible is in full-face view mostly overhung by clypeus, the masticatory margin is edentate, and the apical antennal segment is strongly bulbous.

Vietnamese species (6 spp.).

P. itoi (Forel, 1918) . Au (Chua Yen Tu).

P. longigaster Karavaiev, 1935 . Type locality: Bana [Ba Na, Da Nang]. P. sp. eg-7 [cf. P. japonicum Santschi, 1937 ] (Sa Pa).

P. sp. eg-8 [cf. P. japonicum Santschi ] (Cuc Phuong).

P. sp. eg-10 [cf. P. deelemani Perrault, 1981 ] (Phu Quoc, Pu Mat). P. sp. eg-11 [cf. P. japonicum Santschi ] (Van Ban)

Bionomics. Nests of Proceratium spp. are found in rotting logs and wood fragments in well-developed forests.