Strumigenys lilloana group

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Strumigenys lilloana group Bolton (2000)

Species

Neotropical

Worker Diagnosis

Mandibles in full-face view and at full closure triangular with convex outer margins, broad basally and tapering rapidly toward the apex; masticatory margins serially dentate and engage throughout their length. In ventral view outer margin of mandible without an inflected prebasal angle. MI 17-22.

Dentition. Basal dental row of 6 teeth, followed by 2 smaller teeth, then 3 or perhaps 4 minute denticles and an enlarged apical tooth that overlaps its counterpart at full closure, giving a total dental count of 12 or 13.

Basal lamella of mandible not visible or partially visible with mandibles fully closed.

Labrum terminates in a pair of narrowly to quite broadly digitate lobes that may be acute or bluntly rounded apically.

Clypeus with anterior margin convex in full-face view, the outer margins of the fully closed mandibles intersect the anterior clypeal margin at the anterolateral angles.

Lateral margins of clypeus very short, straight to weakly convex before meeting the upper scrobe margins.

Clypeal dorsum with small appressed very narrowly spatulate hairs, the lateral and anterior margins without specialised or bizarre projecting pilosity.

Preocular carina either not visible in full-face view, concealed by expanded frontal lobe, or its anteriormost portion visible in front of the frontal lobe.

Ventrolateral margin of head marginate between eye and mandibular insertion, margination does not terminate in an anterior tooth. Postbuccal impression very shallow. Ventral surface of head forming a deep convex bulge behind the postbuccal impression, deepest just in front of level of eye.

Upper scrobe margins greatly expanded laterally, in ventral view projecting laterally far beyond the sharply defined ventrolateral margins of the head.

Cuticle of side of head within the scrobe smooth and shining.

Scape very short and subcylindrical, SI 41-48, its leading edge shallowly convex.

Leading edge of scape hairless or at most with minute appressed pubescent hairs that are directed toward the scape apex; without specialised or projecting pilosity of any form.

Pronotum broad and flattened, sharply marginate dorsolaterally, with a narrow translucent cuticular flange anteriorly and much broader in front than behind; without a median carina.

Petiole node in profile with steeply sloping anterior and dorsal faces that meet in a crest or angle, without a differentiated true posterior face; lateral lobe of the node laminate.

Spongiform appendages. Petiole with ventral spongiform to laminate strip and lateral lobes on the node; postpetiole with lateral and ventral lobes. Base of first gastral sternite in profile with a broad pad of diffuse spongiform tissue.

Pilosity. Pronotal humeral' hair simple, curved. Dorsolateral margins of head without projecting hairs; apicoscrobal hair absent. Dorsal (outer) surfaces of tibiae with apically curved subdecumbent to decumbent simple to narrowly spatulate hairs only.

Sculpture. Dorsum of head behind clypeus not reticulate-punctate. Sides of alitrunk smooth and shining.

Notes

Two species are currently included in this group, Strumigenys lilloana, the type-species of the now abandoned genus Chelystruma (Bolton, 1999), and Strumigenys minuscula, a small Brazilian species known only from the holotype.

References