Strumigenys lutron

Identification
Bolton (2000) - S. lutron is immediately separated from other members of the arnoldi-group by having 4 antennal segments, pronotal humeral hair absent, and pronotal disk with densely reticulate punctate sculpture without distinct longitudinal costulae.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  lutron. Strumigenys lutron Fisher, in Bolton, 2000: 633 (w.) MADAGASCAR.

Worker
Holotype. TL 1.6, HL 0.39, HW 0.38, CI 98, ML 0.14, MI 36, SL 0.20, SI 53, PW 0.23, AL 0.42. Characters of lutron-complex. Mandible blade narrow, linear, outcurved; without intercalary denticles between the apical fork teeth. Right mandible with 2 preapical teeth, a short distal tooth and a spiniform proximal tooth located at about the apical third of the length; left mandible with at most a distal preapical denticle but proximal preapical tooth spiniform. Anterior clypeal margin broad, projecting beyond the mandibular bases on each side, with a feeble median impression and with numerous small spatulate to spoon-shaped hairs which are curved towards the midline. Lateral margin of clypeus short. Preocular lamina broad, projecting below the antennal insertion. Median portion of clypeus broad, finely punctulate and with scale-like to spoon-shaped hairs present. Dorsum of head behind clypeus reticulate-punctate and with numerous broadly scale-like to spoon-shaped hairs on anterior two-thirds. Outer margin of frontal lobe and upper scrobe margin with a continuous row of scale-like to spoon-shaped hairs. Hairs on upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair. Eye very small, with 3 ommatidia in total and situated just above the ventral scrobe margin. Antenna with 4 segments. Leading edge of the scape a dorsoventrally flattened convex lamella with a row of projecting scale-like to spoon-shaped hairs. Dorsum of head with a transverse row of 4 hairs close to the occipital margin. Pronotal humeral hair absent. Mesonotum with a pair of short filiform hairs on anterior margin (can be worn). In profile, the promesonotum slightly convex; propodeal dorsum shallowly convex anteriorly, sloping posteriorly to the declivity. Propodeal teeth very short, mostly incorporated in the lamellae, with only a small point projecting. Sides of alitrunk smooth to superficially reticulate-punctate. Dorsal alitrunk and at least the upper half of the propodeal declivity reticulate-punctate, the punctures more strongly defined and denser on the pronotum than on the propodeum, where they may be superficial. Ground-pilosity of dorsal alitrunk consisting of numerous small appressed hairs. In profile the petiole with a well developed spongiform lamella. Dorsal surface of petiole node finely punctate to reticulate, the postpetiole smooth. Petiole, postpetiole and gaster with short simple to narrowly clavate hairs. Colour dull yellow to pale brown.

Paratypes. TL 1.6-1.7, HL 0.39-0.41, HW 0.36-0.38, CI 92-96, ML 0.13-0.15, MI 33-39, SL 0.19-0.21, SI 52-57, PW 0.22-0.24, AL 0.41-0.45 (6 measured). As holotype.

Measurements of non-paratypic material extend the range shown by the type-series: HL 0.39-0.40, HW 0.38, CI 96-98, ML 0.15, MI 38-39, SL 0.20-0.21, SI 52-55 (2 measured).

Type Material
Holotype worker. Madagascar: Provo Toamasina, S. F. Tampolo; 10 km. NNE Fenoarivo Atn., 17°17'S, 49°26'E, 10 m., 4.iv.1997, sifted litter (leaf mold, rotten wood), littoral rainforest #1342 (49)-1 (B. L. Fisher).

Paratypes. 6 workers with same data as holotype but coded (21)-2, (34)-1, (36)-3, (42)-2, (47)-3.