OPAMYRMA

(Subfamily Amblyoponinae)

Taxonomy

Yamane and us recongnized in the Vietnamese ant collection in IEBR (the Institute of Ecology and Biological Resources, Hanoi, Vietnam) an undescribed species. The worker agrees well with the redefinition of Amblyoponinae by Saux et al. (2004), and is very similar to that of the Afrotropical genus Apomyrma established by Brown et al. (1971). And then Yamane et al. (2008) established the monotypic genus Opamyrma for this bizarre species (O. hungvuong). The diagnosis are as follows, and the features which support the independence at the genus level from Apomyrma (see Brown et al 1971; Bolton 1994, 2003) were highlighted below in bold.

  • Preoccipital carina strongly present.
  • Posteromedian part of clypeus broadly inserted between antennal socket, and boundered by weak fronto-clypeal suture.
  • Lateral part of clypeus narrow from front to back.
  • Outer face of labrum with numerous peg-like setae present.
  • Eye absent.
  • Antenna 12-segmented, gradually incrassate from segment III to XII.
  • Frontal lobe absent.
  • Antennal sockets horizontal (directing dorsad), exposed in full-face view.
  • Promesonotal suture present and flexible.
  • Propodeal spiracle situated relatively low and posteriorly on the side.
  • Propodeal spine absent.
  • Metapleural lobe absent.
  • Pretarsal claws without a preapical tooth.
  • Waist consisting of a single segment (petiole).
  • Petiole narrowly attached to abdominal segment III.
  • Petiolar peduncle absent.
  • Abdominal segment III above the helcium having a free anterior face.
  • Anteriormost part of abdominal sternite III produced anteriad to the same level as the anteriormost part of the tergite III.
  • Abdominal segment IV with differentiated presternite.
  • Abdominal spiracles 5–7 concealed by the posterior margins of the preceding segments.
  • Pygidium large and simple, unarmed, convex across and down-curved posteriorly.
  • Sting developed very well.

Based on the discovery of Opamyrma, Yamane et al. (2008) revived the tribe Amblyoponini and Apomyrmini under the subfamily Amblyoponinae. The former involves eight extant genera, i.e. Adetomyrma, Amblyopone, Bannapone, Concoctio, Myopopone, Mystrium, Onychomyrmex and Prionopelta, and the latter involves Apomyrma and Opamyrma. Although, according the molecular phylogeny proposed by Saux et al. (2004), the tribe Amblyoponini is non-monophyletic, the revival of the tribes may provide a good working hypothesis for our further understanding of morphological diversity of ants.

Diagnosis of Amblyoponini are:

  • Anterior clypeal margin bearing dentiform setae (with a single exception: Amblyopone mutica).
  • Frontal lobe large to much reduced, but not absent.
  • Antennal socket directing dorsolaterad.
  • Abdominal segment III above the helcium lacking a free anterior face.

Diagnosis of Apomyrmini are:

  • Outer face of abrum instead of anterior clypeal margin bearing peg-like setae.
  • Frontal lobe absent.
  • Antennal socket directing dorsad.
  • Abdominal segment III above the helcium having a free anterior face.

Images


Opamyrma hungvuong, worker, body in lateral view.


Opamyrma hungvuong, worker, head in full-face view.


Opamyrma hungvuong, worker, mesosoma and waist in dorsal view.

Distribution

The monotypic genus Opamyrma has so far been known only once from the type locality (northern Middle Vietnam). Its possible relatives, Apomyrma stygia, are Afrotropical.

hungvuong Yamane, Bui et Eguchi Huong Son (Ha Tinh)

Bionomics

The type series of Opamyrma hungvuong were collected inside a log on the forest floor.

© Katsuyuki EGUCHI & BUI Tuan Viet, 2007. All rights reserved.