Strumigenys dicomas

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Strumigenys dicomas
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. dicomas
Binomial name
Strumigenys dicomas
Fisher, 2000

Strumigenys dicomas casent0005519 profile 1.jpg

Strumigenys dicomas casent0005519 dorsal 1.jpg

Specimen labels

Judging from the more than one hundred collections of this ant, it nests in dead wood on the ground. It has been found in rotten logs, stumps and a downed stick, in addition to having been found in many litter samples.

Identification

Bolton (2000) - The only member of the Strumigenys koningsbergeri-group from the Malagasy region. S. dicomas is widely distributed but easily recognized. In the Malagasy region it is the only species with the mandible shape and dentition as described below.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Comoros.
Malagasy Region: Madagascar (type locality), Mayotte.


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Worker

Queen

Male

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • dicomas. Strumigenys dicomas Fisher, in Bolton, 2000: 655, figs. 394, 416 (w.q.) MADAGASCAR.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Holotype. TL 3.6, HL 1.01, HW 0.93, CI 93, ML 0.48, MI 47, SL 0.63, SI 67, PW 0.42, AL 0.86. With the above characters and the following. Outer margins of mandibles shallowly convex in full-face view. Upper scrobe margin bordered by a conspicuous laminate rim or flange throughout its length; eyes partially visible in full-face view. Leading edge of scape with a row of slender hairs which are slightly flattened or spoon-shaped apically. Cephalic dorsum clothed with inconspicuous small curved spatulate to narrowly spoon-shaped ground-pilosity; the upper scrobe margin fringed with hairs which are similar in shape and size as those on the dorsum; apicoscrobal hair absent. Cephalic dorsum with 6 simple standing hairs arranged in a transverse row close to the occipital margin; many paratypes have a more anteriorly situated pair near the highest point of the vertex. Dorsum of head reticulate-punctate, middorsum rugulose in larger specimens. Mesonotum with a single pair of stout standing hairs situated on anterior margin. Propodeum without a pair of short, fine, posteriorly curved hairs immediately anterior of propodeal spines. Ground-pilosity on alitrunk as on head but sparser. With the alitrunk in profile the posterior portion of the mesonotum sharply depressed, the metanotal groove represented by a shallow impression. Pronotal humeri rounded. Dorsolateral margin of posterior pronotum bluntly marginate. Anterior mesonotum with a distinct narrow carina above the mesothoracic spiracle. Propodeal spine long and slender, recurved, especially near the apex; propodeal lamella absent. Alitrunk dorsum reticulate-punctate; lateral margins of pronotum rugulose; pleurae more or less smooth centrally with peripheral reticulate-punctate sculpture. Petiole node in dorsal view finely reticulate-punctate, exposed area of cuticle slightly broader than long. Postpetiole superficially reticulate-punctate. Spongiform appendages of petiole weakly developed, with a narrow ventral curtain. Postpetiole with small but distinct lateral and ventral spongiform lobes. Basigastral costulae short and distinct; gaster smooth and shiny when clean. Dorsal surfaces of petiole, postpetiole, and gaster with stout standing hairs which are swollen apically. Colour dull yellow to light medium brown.

Paratypes. TL 3.6-4.2, HL 1.00-1.17, HW 0.91-1.11, CI 90-95, ML 0.48-0.55, MI 46-49, SL 0.62-0.70, SI 63-68, PW 0.41-0.49, AL 0.81-1.02 (9 measured). As holotype.

The non-paratypic material shows greater size variation than the type-series alone: HL 0.86-1.09, HW 0.75-1.04, CI 87-95, ML 0.41-0.52, MI 42-50, SL 0.53-0.68, SI 61-75 (12 measured), but otherwise matches all diagnostic characters.

Type Material

Holotype worker, Madagascar: 9.2 km. WSW Befingotra, Res. Anjanaharibe-Sud, 14°45'S, 49°28'E, 1200 m., 9.xi.1994, sifted litter (leaf mold rotten wood), montane rainforest #1192 (12)-14 (B. L. Fisher) (Museum of Comparative Zoology).

Paratypes. 9 workers and 2 queens (dealate) with same data as holotype but coded (3)-9, (23)-9, (24)-9, (24)-10, (29)-8, (36)-9, (40)-4, (50)-10, (L. O.)-10 (The Natural History Museum, South African Museum).

References

  • Fisher, B.L. 2000. The Malagasy fauna of Strumigenys. Pp. 612-696 in: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 655, worker described)