Strumigenys chroa Fisher, 2000

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 : 674-675

Strumigenys chroa Fisher sp. n. (Figs 404, 420)

HOLOTYPE WORKER. TL 3.2, HL 0.80, HW 0.67, CI 84, ML 0.30, MI 38, SL 0.44, SI 66, PW 0.35, AL 0.81. Characters of chroa-complex. Mandibles almost straight and at full closure parallel except at base. Proximal preapical tooth on mandible confluent with lamella on inner margin that extends to base; in full-face view inner margin of lamella more or less straight. Upper scrobe margin a broad lamella, about as wide as scape. Eye small, with about 10 ommatidia in total. Hairs on leading edge of scape slender and filiform. Cephalic dorsum densely clothed with rows of curved narrow spatulate to spoonshaped ground-pilosity, the upper scrobe margins fringed with a dense row of hairs which are the same shape and size as those on the dorsum. Cephalic dorsum with 6 simple standing hairs arranged in a transverse row of 4 close to the occipital margin and a more anteriorly situated pair. Pronotal humeral hair absent. Anterior margin of mesonotum with a pair of clavate to remiform hairs; posterior mesonotum with 2 additional pairs which are similar in shape to anterior pair but shorter. Ground-pilosity on alitrunk as on head. Dorsum of alitrunk in outline convex anteriorly and more or less flat posteriorly; posterior portion of mesonotum slightly depressed below the anterior margin of propodeum. Anterior mesonotum sharply marginate laterally, forming a convex lamellate extension above the mesothoracic spiracle. Propodeal tooth lamellate and confluent with the greatly expanded lamella for more than half its length. Alitrunk dorsum reticulate-punctate; pleurae mostly smooth and shiny, peripherally reticulate-punctate. Disc of postpetiole smooth and shiny, in dorsal view conspicuously broader than long. Ventral and lateral spongiform tissue of petiole and postpetiole greatly developed; ventral spongiform tissue of petiole marginate medially. Base of first gastral tergite with a continuous row of costulae. Dorsal surfaces of petiole, postpetiole and gaster with stout standing hairs which are thickened apically. Colour dull yellowish brown.

PARATYPE WORKERS. TL 3.1 - 3.3, HL 0.77 - 0.82, HW 0.68 - 0.70, CI 86 - 88, ML 0.29 - 0.31, MI 37 - 38, SL 0.41 - 0.46, SI 61 - 65, PW 0.33 - 0.37, AL 0.78 - 0.86 (3 measured). As holotype.

Holotype worker, Madagascar: Prov. Toliara, southern Isoky-Vohimena Forest, 22 ° 41 ' S, 44 ° 50 ' E, 730 m., 21. i. 1996 (S. Razafimandimby) (MCZ).

Paratypes. 1 worker with same data as holotype; 2 workers with same data but labeled sifted litter (leaf mold, rotten wood), dry forest and coded # 1312 (9) - 3, and (6) - 4 (BMNH, SAM).

NON-PARATYPIC MATERIAL EXAMINED. Madagascar: Montagne d'Ambre N. P. Petit Lac, 1000 m. (Alpert el al.); Montagne d'Ambre (Taiti & Bartolozzi); R. S. Manongarivo, 12.8 km. 228 ° SW Antanambao, 780 m. (B. L. Fisher); R. S. Manongarivo, 14.5 km. 220 " SW Antanambao, 1175 m. (B. L. Fisher); Marojejy R. N. I. # 12 (G. D. Alpert); F. C. Didy, 960 m. (H. J. Ralsirarson); F. C. Andrianantantely, 530 m. (H. J. Ralsirarson); 7 km. W Ranomafana (WE. Steiner); Ranomafana Nat.

Park (£. Rajeriarison); 29 km. NNW Ranohira, Isalo N. P. (Alpen el al.); 28 km. NNW Ranohira, Isalo N. P. (O. D. Alperl).

This material included workers from higher elevations that were larger than the type-series: HL 0.80 - 0.93, HW 0.64 - 0.77, CI 80 - 84, ML 0.31 - 0.36, MI 36 - 41, SL 0.43 - 0.52, SI 66 - 72 (11 measured).

A widely distributed but easily recognized member of the chroa-complex, this species is recognized by its lamellate upper scrobe margin, absence of a pronotal humeral hair and marginate ventral spongiform tissue of petiole.