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Strumigenys bubisnoda group
Strumigenys bubisnoda group Bolton (2000)
Species
Malesian-Oriental-East Palaeartic
Worker Diagnosis
Mandibles in full-face view and at full closure short subtriangular, broad, with flat dorsal surfaces and convex lateral margins. Masticatory margins serially dentate and the tooth rows engage through the lengths of the margins. In profile mandible almost straight, distal half only very feebly angled downward with respect to proximal half. In ventral view outer margin of mandible without an inflected prebasal angle. MI 11.
Dentition. Basally with a dental row of 6-7 closely crowded slender spiniform teeth. Distal to this basal series the masticatory margin with an indistinct number denticles; total dental count cannot be assessed in the single specimen available.
Basal lamella of mandible not visible in single known specimen.
Labrum terminates in a pair of elongate digitate narrow lobes.
Clypeus with anterior margin evenly convex, lateral margins approximately parallel; dorsum of clypeus flat. Outer margin of mandible intersecting anterior clypeal margin very close to clypeal anterolateral angles. In ventral view the lateral clypeal margins extend well beyond the outer margins of the fully closed mandibles through the basal third or more of their length.
Clypeal anterior margin with a continuous dense fringe of anteriorly projecting minute spatulate hairs; this fringe extends just round anterolateral angles but peters out on the lateral margins. Dorsum of clypeus without standing hairs but with scattered minute pubescent hairs that are very inconspicuous.
Preocular carina visible in full-face view.
Head in profile extremely dorsoventrally flattened, its maximum depth in profile only about 0.40 X HW.
Cuticle of side of head within scrobe very finely and densely reticulate-punctate.
Scape short, SI 60, dorsoventrally flattened and with a sharp leading edge.
Leading edge of scape with a row of short spatulate or flat delta-shaped hairs, all of which are inclined or angled toward the apex of the scape.
Pronotum marginate dorsolaterally; dorsum without a median longitudinal carina.
Propodeum broadly and bluntly bidentate, lamella on declivity a minute ear-shaped lobe; side of propodeum forms a V-shaped concavity at the apex of which is the spiracle; orifice of spiracle directed posteriorly.
Petiole in profile long and low; node with anterior face very short, much shorter than the elongate, shallowly curved dorsum. In dorsal view petiole node much longer than broad. Postpetiole enormously swollen and subglobular.
Spongiform appendages present on petiole and postpetiole. Base of first gastral sternite in profile with a pad of spongiform tissue.
Pilosity. Very reduced; apart from fringing pilosity of clypeus, upper scrobe margins and scapes standing hairs restricted to 1-2 pairs on first gastral tergite and a few near gastral apex. Standing pilosity absent from cephalic dorsum and promesonotum.
Pronotal humeral hair absent. Ground-pilosity on head and body sparse, minute and subappressed to appressed.
Sculpture. Clypeus almost smooth, gaster mostly smooth and basigastral costulae absent; remainder of head and body punctate.
Notes
Only a single species is currently assigned to this group, Strumigenys bubisnoda. Like many morphologically isolated species this one is a mass of autapomorphic characters, which makes it very easy to define but very difficult to associate with other taxa. The shape of the petiole is, however, the same as that seen in the leptothrix group, and that is probably the origin of bubisnoda.
The head of this species has a similar morphology to the extremely flat-headed species of the Neotropical (Strumigenys depressiceps) and Afrotropical (Strumigenys terroni, Strumigenys tethepa) regions. This head shape has certainly been acquired by convergence as their morphology otherwise indicates an independent origin for each. The various species probably occupy the same ecological niche on the various continents.
References
- Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.