Leptogenys Roger, 1861

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 : 34-36

Leptogenys Roger, 1861

Taxonomy. The genus Leptogenys is assigned to the tribe Ponerini ( Bolton 2003) .

Morphology. Although the species of this genus are highly variable in worker morphology, Workers of Vietnamese species have the following features (see also Schmidt & Shattuck 2014):

Worker monomorphic; head in full-face view roughly oval or subrectangular; preoccipital carina usually conspicuous dorsally and laterally; frontal lobes horizontal or suberrect, narrowly separated from each other by posteromedian portion of clypeus, or a longitudinal sulcus; antennal socket in full-face view largely exposed; antennal scrobe absent; median portion of clypeus strongly produced anteriad as a triangular, subrectangular or round lobe that usually bears 1 to several peg-like setae at apex; mandible variable in shape, subtriangular, linear or falcate; mandible with apical tooth or corner; basal angle usually (but not always) present as a corner or tooth; masticatory margin edentate or with less than 10 teeth; basal margin sometimes with several small dents; antenna 12-segmented; eye always present, but variable in size, usually (but not always) located before midlength of side of head in lateral view; mesosoma in lateral view with a straight or weakly convex dorsal outline, or pronotum more or less raised; promesonotal suture completely separating pronotum from mesonotum; metanotal groove often distinct dorsally; mesonotum often present as a distinct disc well margined anteriorly by promesonotal suture and posteriorly by metanotal groove; mesopleuron defined dorsally and posteriorly by carinae or sulci; propodeum usually unarmed, but sometimes with a process or ridge just above metapleural gland; orifice of propodeal spiracle round or elliptical; propodeal lobe indistinct or absent; apicoventral part of foretibia without a small simple spur behind a large pectinate spur; apicoventral part of mid and hind tibiae with a small, simple or barbulate spur in front of a large barbulate or pectinate spur; pretarsal claws of hind leg armed with several teeth on the inner margin (the teeth usually remarkable, but rarely very small); petiole without distinct anterior peduncle; petiolar node in lateral view variable in shape; subpetiolar process variable in size and shape, located at anteroventral part of petiole; girdling constriction between abdominal segments III and IV weak to distinct; abdominal sternite III usually with an anteroventral flange beneath helcium (flange sometimes indistinct and/or hidden by posterolateral margin of petiole); sting well developed.

The ergatoid queen is morphologically very similar to the worker, but the former usually has a larger propodeum, thinner petiolar node (in lateral view) and more or less expanded gaster. This may cause misdetermination at the species level.

Differentiation. The worker of Leptogenys is easily distinguished from that of the other Ponerinae known from Vietnam by the combination of the following features: the anteromedian portion of clypeus being well produced anteriad; the pretarsal claws of the hind leg armed with 1 to many teeth on the inner margin.

Vietnamese species (40 spp.).

L. aspera (André, 1889) . Type locality: Hue.

L. birmana Forel, 1900 . Au (Pu Mat, Pu Hoat), Zry (Cat Tien).

L. borneensis Wheeler, 1919 . Zry (Cat Tien).

L. chinensis (Mayr, 1870) . Zry (Cat Tien).

L. crassicornis Emery, 1895 . Zry (Cat Tien).

L. davydovi Karavaiev, 1935 . Type locality: Bana [Ba Na, Da Nang].

L. diminuta (F. Smith, 1857) . Au (Ba Be, Chua Yen Tu, Cuc Phuong, My Yen, Nam Cat Tien, Pu Mat, Tam Dao, Tay Yen Tu), Rad (Cuc Phuong, nr. Ha Noi), Zry (Cat Tien).

L. kitteli (Mayr, 1870) . Au (Ba Vi, Cuc Phuong, Cat Tien, Chua Yen Tu, Phu Quoc, Pu Mat, Sa Pa, Tay Yen Tu, Van Ban), Rad (Cuc Phuong, Ha Noi, Hoa Binh), Zry (Cat Tien).

L. kraepelini Forel, 1905 . Au (Ba Vi, Cuc Phuong, Pu Mat, Sa Pa, Tay Yen Tu).

L. lucidula Emery, 1895 . Rad (Cuc Phuong).

L. minchinii Forel, 1900 . Rad (nr. Ha Noi), Zry (Cat Tien).

L. pangui Xu, 2000 . Zry (Cat Tien).

L. parvula Emery, 1900 . Au (Cuc Phuong).

L. peuqueti (André, 1887) . Type locality: Hue. Au (Cat Tien, Pu Mat).

L. processionalis ( Jerdon, 1851) [senior synonym of L. distinguenda andrei (Emery) ]. Type locality of “ L. distinguenda andrei ”: Cocincina [southern Vietnam]. Zry (Cat Tien)

L. sp. eg-3 [= sp. 61 of SKY in Eguchi, Bui et al. (2005)] (Chua Yen Tu, Tam Dao).

L. sp. eg-4 (Cat Tien, Tay Yen Tu).

L. sp. eg-5 (Tay Yen Tu).

L. sp. eg-6 [= sp. 38 of SKY in Eguchi, Bui et al. (2005)] (Ba Vi).

L. sp. eg-7 [= sp. 50 of SKY in Eguchi, Bui et al. (2005)] (Cuc Phuong, Pu Mat, Tam Dao, Tay Yen Tu).

L. sp. eg-8 [= sp. 58 of SKY in Bui et Eguchi (2003)] (Sa Pa).

L. sp. eg-9 [= sp. 53 of SKY in Eguchi, Bui et al. (2005)] (Ba Vi, Cuc Phuong, Pu Mat, Tay Yen Tu).

L. sp. eg-10 [= sp. 29 of SKY in Yamane et al. (2003)] (Chua Yen Tu, Cuc Phuong, Sa Pa, Tay Yen Tu).

L. sp. eg-12 (Ba Vi, Cuc Phuong, Phu Quoc).

L. sp. eg-13 (Ba Vi, Sa Pa).

L. sp. eg-14 (Binh Chau-Phuoc Buu, Nui Chua, Phu Quoc, Pu Mat, Tay Yen Tu).

L. sp. eg-15 (Cat Tien, Nui Chua).

L. sp. eg-16 (Pu Mat).

L. sp. eg-18 (Cat Tien).

L. sp. eg-20 (Cat Tien).

L. sp. eg-23 (Cat Tien).

L. sp. eg-24 [= sp. 36 of SKY in Yamane et al. (2003)] (Cuc Phuong).

L. sp. eg-25 (Cat Tien).

L. sp. eg-26 (Cat Tien, Nui Chua).

L. sp. eg-27 (Cat Tien, Phu Quoc).

L. sp. eg-28 (Cat Tien, Nui Chua, Phu Quoc).

L. sp. eg-29 (Cat Tien).

L. sp. eg-30 (Pu Mat).

L. sp. eg-31 (Cat Tien, Nui Chua).

L. sp. eg-32 [= sp. 41 of SKY in Yamane et al. (2003)] (Cuc Phuong). One subspecies was also described from Vietnam: L. kraepelini baccha Santschi (type locality: Tonkin: Chapa [Sa Pa]).

Bionomics. Leptogenys spp. usually occur in well-developed forests and other woody habitats. They forage on insects and other invertebrates living on the ground and in litter, and nest in rotting logs and wood fragments, and in litter and soil. Part of the species are nomadic. A few Vietnamese species seem to be subterranean (captured often by underground bait trapping). Colony sizes are variable among the species, probably less than 100 to over 10,000.