Ectomomyrmex Mayr, 1867

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 : 31-32

Ectomomyrmex Mayr, 1867

Taxonomy. The genus Ectomomyrmex was synonymized with Pachycondyla by Brown in Bolton (1994), and assigned to the tribe Ponerini ( Bolton 2003) . However, based on a recent molecular phylogenetic analysis ( Schmidt 2013), Schmidt & Shattuck (2014) revived Ectomomyrmex as an independent genus, and placed it under the Ponera genus group of the tribe Ponerini .

Morphology. Workers of Vietnamese species have the following features (see also Schmidt & Shattuck 2014):

Worker monomorphic; head, mesosoma and petiole conspicuously striate, rugoso-reticulate or punctate, and gaster usually finely punctate; head in full-face view subrectangular or subtrapezoidal; preoccipital carina inconspicuous dorsally; frontal lobes horizontal, separated from each other just with a longitudinal sulcus; antennal scrobe absent; anteromedian margin of clypeus roundly convex, sometimes with a weak median emargination or an indistinct tooth (but never forming a rectangular projection); mandible subtriangular, with 7–10 teeth on masticatory margin; basal portion of mandible without a circular or near-circular pit or fovea dorsolaterally; antenna 12-segmented, gradually incrassate from segment III to XII; eye small to moderate in size, located on side of head relatively close to mandibular insertion; mesosoma in lateral view with a straight or weakly convex dorsal outline; promesonotal suture completely separating pronotum from mesonotum; metanotal groove absent or reduced to an inconspicuous suture; mesopleuron separated well from mesonotum and metapleuron with distinct sutures, divided by a transverse groove; propodeum unarmed; orifice of propodeal spiracle slit-like; propodeal lobe very low or almost absent; apicoventral part of foretibia with a small simple spur behind a large pectinate spur; apicoventral part of mid and hind tibiae with a simple spur in front of a large pectinate spur; outer surface of middle tibia with normal pilosity only; petiolar node squamiform to nodiform, in lateral view high and relatively thick; subpetiolar process developed, but simple in shape, without an anterior fenestra/fovea and a pair of teeth; girdling constriction between abdominal segments III and IV distinct; abdominal sternite III usually with a distinct anteroventral flange beneath helcium, or with a U-shaped or V-shaped ridge below helcium; abdominal tergite III weakly punctate; sting well developed.

Differentiation. The worker of Ectomomyrmex is similar to that of Pseudoneoponera or Bothroponera . In the worker of Pseudoneoponera , however, posterior margin of petiole has a row of small teeth or denticles, and the abdominal tergite III is longitudinally striated. In the worker of Bothroponera , mesopleuron is usually not divided by a transverse groove. Furthermore, the worker of the Asian species of Bothroponera lacks the strongly sculptured body. The worker of the smaller species of Ectomomyrmex is somewhat similar to that of some Euponera spp., but in the latter the basal portion of mandible has a pit dorsolaterally.

Vietnamese species (9 spp.).

E. annamitus (André, 1892) . Type locality: Hue. Rad (Ha Noi), Zry (Cat Tien).

E. astutus ( F. Smith, 1858) . Rad (Cuc Phuong, nr Ha Noi), Zry (Cat Tien).

E. leeuwenhoeki (Forel, 1886) . Zry (Cat Tien).

E. lobocarenus (Xu, 1995) . Zry (Cat Tien).

E. punctatus (Karavaiev, 1935) . Type locality: Bana [Ba Na, Da Nang]. Rad (Cuc Phuong, Hoa Binh).

E. tonkinus (Santschi, 1920) . Type locality: Ha Noi.

E. sp. eg-1 [cf. E. astutus ; = Pachycondyla sp. 26 of SKY in Eguchi, Bui et al. (2005)] (Ba Vi, Cat Tien, My Yen, Pu Mat, Sa Pa, Tam Dao, Tay Yen Tu).

E. sp. eg-2 [cf. E. astutus ] (Cat Tien, Phu Quoc).

E. sp. eg-3 [cf. E. leeuwenhoeki ] (Ba Vi, Cat Tien, Cuc Phuong, Pu Mat, Tay Yen Tu, Van Ban).

One subspecies was also described from Vietnam: Ectomomyrmex astutus obscura (Karavaiev, 1935) (type locality: Phu-ho, Tonkin [possibly Phu Ho, Phu Tho Prov.]).

Bionomics. Ectomomyrmex spp. usually occur in well-developed forests and other wooded habitats. They nest in rotting logs, wood fragments, under stones and in soil.