HOLOTYPE WORKER. TL 2.4, HL 0.66, HW 0.57, CI 88, ML 0.12, MI 18, SL 0.29, SI 51, PW 0.36, AL 0.68. Characters of
PARATYPE WORKERS. TL 2.4 - 2.5, HL 0.65 - 0.66, HW 0.58 - 0.59, CI 88 - 90, ML 0.12 - 0.13, MI 18 - 20, SL 0.29, SI 49 - 50, PW 0.36 - 0.37, AL 0.68 (2 measured). As holotype.
Holotype worker, Madagascar: 45 km. S Ambalavao, 22 ° 13 ' S, 47 ° 01 ' E, 785 m., 25. ix. 1993, sifted litter (leaf mold, rotten wood), rainforest, # 696 (40) - 6 (B. L. Fisher) (MCZ).
Paratypes. 1 worker with same data as holotype; 1 worker with same data but # 696 (20) - 9 (SAM, BMNH).
NON-PARATYPIC MATERIAL EXAMINED. Madagascar: 6.5 km. SSW Befingotra, Ris. Anjanaharibe-Sud 875 m. (B. L. Fisher); 6.9 km. NE Ambanizana, Ambohitsitondroina 825 m. (B. L. Fisher); S. F. Tampolo, 10 km. NNE Fenoarivo Atn. 10 m. (B. L. Fisher); Rte. d'Anosibe, km. 33 (A. Peyrieras); F. C. Sandranantitra 450 m. (H. I. Ratsirarson); F. C. Andriantantely 530 m. (H. J. Ratsirarson); Ranomafana Nat. Park, Vohiparara forest 1160 m. (E. Rajeriarison); 43 km. S Ambalavao, Ris. Andringitra 825 m. (B. L. Fisher); 9.0 km. NE Ivohibe 900 m. (S. Razqfimandimby); R. S. Ivohibe 8.0 km. E Ivohibe 1200 m. (5. Razafimandimby); 11 km. NW Enakara, Ris. Andohahela 800 m. (B. L. Fisher).
Members of these series tend to be a little larger than the type-series and to have the head fractionally broader, HL 0.68 - 0.70, HW 0.63 - 0.64, CI 90 - 93, ML 0.12 - 0.13, MI 17 - 19, but otherwise match the types perfectly.
Within the group dexis is related to coveri , gorgon , peyrierasi and rabesoni, a complex of five species that share a distinctive form of sculpture in which cephalic and promesonotal punctures are spaced out and separated by areas of smooth cuticle, rather than having the entire surface opaque and blanketed with reticulate- punctate sculpture (promesonotal punctures absent in carolinae ). Of these five species dexis is identified by its relatively short mandibles, broad head and unique labrum, where both anterior lobes sport a single fan-like lamella of very thin translucent cuticle that projects anteriorly. In addition:
1 The petiole node in coveri is as long as or longer than broad in dorsal view (distinctly broader than long in dexis ).
2 The head has large spoon-shaped hairs on the dorsum of the occipital lobes in gorgon (absent in dexis ).
3 The punctate sculpture of the vertex is much denser and more crowded in rabesoni than in dexis .
4 The mesonotum has a single pair of short straight standing hairs in peyrierasi (absent in dexis ).
The presence of dense blanketing reticulate-punctate sculpture on the dorsum of the head distinguishes the sylvaini-complex from dexis and its immediate allies discussed above. Beside the sculpture alperti and carolinae have a unique distribution of scale-like hairs anteriorly on the cephalic dorsum, and sylvaini and wardi have standing hairs on the head and body, neither of which occurs in the four species of the (feus-complex.
