Strumigenys apios-group

Bolton, B., 2000, The ant tribe Dacetini. With a revision of the Strumigenys species of the Malgasy Region by Brian L. Fisher, and a revision of the Austral epopostrumiform genera by Steven O. Shattuck., Memoirs of the American Entomological Institute 65, pp. 1-1028 : 625

apios-group

DIAGNOSIS OF WORKER

Apical fork of mandible with three spiniform teeth, the apicoventral tooth the shortest; without intercalary dentition. Preapical teeth absent or left mandible with a denticle or small tooth close to the apicodorsal tooth. Mandible in full-face view with blades almost straight and at full closure parallel. MI 54 - 68.

Scape slender and subcylindrical. SI 119 - 138.

Ventrolateral margin of head with preocular notch vestigial or absent; ventral preocular impression in the head absent.

Eye with maximum diameter exceeding maximum width of scape.

Scrobe vestigial or absent behind level of eye; dorsolateral margin of head not sharply defined behind eye, the cephalic dorsum rounding into the side.

Spongiform appendages of petiole absent. Postpetiole with ventral and lateral lobes reduced or absent; spongiform collar present.

Pilosity. Pronotal humeral hair usually absent. Apicoscrobal hair absent; upper scrobe margin without row of hairs. Cephalic ground-pilosity scale-like. Cephalic dorsum with 4 standing hairs, arranged as a transverse row near occipital margin; vertex without standing pair of hairs. Dorsal alitrunk without standing hairs. First gastral tergite with standing hairs which are simple or slightly thickened apically.

Sculpture. Head, dorsal alitrunk and petiole reticulate-punctate. Gaster unsculptured except for basigastral costulae.

Glands. Gland of scape visible as an elongate patch of pale tissue along the midsection of the ventral surface. Femoral gland bullae decreasing in size from hind femur where it is easily visible to the fore femur where it is minute to absent. Tibial gland bulla absent on all tibiae ( apios ) or present on fore and hind tibiae ( agra ). Gland at base of calcar conspicuous. Tarsal glands visible on at least first three tarsi, decreasing in size from basitarsus where it is elongate to the third tarsal segment where it is oval. Mesopleural gland visible and set in a narrow circular notch or a broad concave impression.

Members of the apios-group are easily distinguished by their combination of long cylindrical scape, apical fork of mandible composed of 3 spiniform teeth, very reduced or absent preapical dentition, long propodeal spines that are slender and recurved and the absence of a preocular notch. The two species included here are convergent on the southeast Asian szalayi-group and the kraepelini-complex of the mayri-group but are clearly derived from the Malagasy grandidieri-group .