Strumigenys scotti Forel

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 : 694-695

Strumigenys scotti Forel

Strumigenys scotti Forel , 1912 c: 159. Syntype workers, SEYCHELLE IS: Silhouette, Mare aux Cochons, 1000 ft (H. Scott) (BMNH, MHN) [examined].

[ Strumigenys scotti : W. M. Wheeler, 1922 a: 1034 and Emery, 1924: 320 (catalogues); Brown, 1954 f: 23 and Bolton, 1983: 391 (descriptions of worker); Bolton, 1995 b: 398 (catalogue).]

WORKER. TL 2.7 - 3.1, HL 0.64 - 0.70, HW 0.46 - 0.52, CI 70 - 74, ML 0.30 - 0.34, MI 46 - 49, SL 0.39 - 0.47, SI 84 - 92, PW 0.31 - 0.36, AL 0.71 - 0.80 (14 measured). Characters of scotti-complex. Mandibles in full-face view with outer margins very shallowly and evenly convex, the width approximately constant from the level of the proximal preapical tooth to near the base. Upper scrobe margin evenly and shallowly convex in full-face view, not bordered by a rim or flange, the eyes visible. Maximum diameter of eye distinctly greater than maximum width of scape, with 5 - 6 ommatidia in longest row. Scape long slender and subcylindrical, only very feebly curved near the base; hairs on leading edge small, slender, slightly flattened or spoon-shaped apically. Cephalic dorsum densely clothed with curved narrow spatulate to spoon-shaped 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 flagellate. Mesonotum with a single pair of standing hairs, rarely with one or two pairs of short decumbent filiform hairs situated posteriorly on the mesonotum. Propodeum with one pair of short, posteriorly curved hairs immediately anterior of propodeal spines. Ground-pilosity on alitrunk as on head but the hairs smaller and sparser. Posterior portion of mesonotum shallowly depressed behind the level of the standing hairs. Anterior mesonotum with a narrow carina above the mesothoracic spiracle; mesopleural gland set in a small circular notch. Propodeal tooth triangular, lamellate, pointed apically, and subtended by a narrow lamella. Pronotal dorsum longitudinally feebly rugulose and punctate, with a longitudinal carina mid-dorsally. Remainder of dorsal alitrunk reticulate-punctate. Sides of alitrunk superficially punctulate peripherally, the pleurae mostly smooth. Petiole node in dorsal view at least as long as broad, often longer than broad. Postpetiole disc smooth and shining. Spongiform appendages well developed, the petiole with a ventral strip and conspicuous lateral lobe on the node; postpetiole with large lateral and ventral spongiform lobes of which the ventral is the larger, about as large as the exposed area of the postpetiole disc in profile. In dorsal view the spongiform material not or only very slightly projecting beyond the lateral outline of the disc. Basigastral costulae arising on each side of a central clear area. Dorsal surfaces of petiole, postpetiole and gaster with standing hairs which are simple or very slightly thickened apically. Colour yellowish brown to medium brown.

A widely distributed but easily recognized member of the scotti-complex. Among the species which have the dorsum of the petiole node reticulate-punctate, scotti is the only one with the following characters in combination.

1 The mesonotum with only a single pair of erect hairs, located at the anterior margin.

2 A well developed spongiform curtain ventrally on petiolar peduncle.

3 A transverse band of appressed spoon-shaped hairs arranged in several rows on the cephalic dorsum immediately behind the clypeus.

4 Postpetiole smooth and shiny, even at lateral margins. In addition its large size, HL 0.64 - 0.70, HW 0.46 - 0.52, helps to characterise this species. Afrotropical material considered to be scotti by Bolton (1983) is now referred to a separate species, sibyna; see there.

MATERIAL EXAMINED

Seychelles Is: Silhouette I. (H. Scott). Madagascar: R. S. Manongarivo, 14.5 km. 220 ° SW Antanambao, 1175 m. (B. L. Fisher); Marojejy, 375 m. (Alpert et a /.); 17 km. W Andapa, Res. d'Anjanaharibe-Sud, 875 m. (G. D. Alpert); Nosy Mangabe, 300 m. (P. S. Ward); 1 km. W Andampibe, Cap Masoala, 125 m. (G. D. Alperi); F. C. Didy, 960 m. (H. J. Ratsirarson); EC. Andrianantantely, 530 m. (H. J. Ratsirarson); Tananarive, Botanical Garden (P. Saranya); Perinet (W. L. Brown); 27.4 km. S Ambositra, 1600 m. (B. L. Fisher); 3 km. W Ranomafana, 950 m. (P. S. Wtrd); 40 km. S Ambalavao, Res. Andringitra, 1275 m. (B. L. Fisher); 45 km. S Ambalavao, 785 m. (B. L. Fisher); R. S. Ivohibe, 7.5 km. ENE Ivohibe, 900 m. (S. Razafimandimby); 8.0 km. E Ivohibe, R. S. Ivohibe, 1200 m. (S. Razafimandimby); 10 km. NW Enakara, Res. Andohahela, 430 m. (B. L. Fisher); 13 km. NW Enakara, Res. Andohahela, 1250 m. (B. L. Fisher).