Strumigenys dicomas

AntWiki: The Ants --- Online
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

Latitudinal Distribution Pattern

Latitudinal Range: -13.962° to -14.75°.

 
North
Temperate
North
Subtropical
Tropical South
Subtropical
South
Temperate

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

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.
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Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.
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Biology

Castes

Worker

Images from AntWeb

Strumigenys dicomas casent0005521 head 1.jpgStrumigenys dicomas casent0005521 profile 1.jpgStrumigenys dicomas casent0005521 dorsal 1.jpgStrumigenys dicomas casent0005521 label 1.jpg
Holotype of Strumigenys dicomasWorker. Specimen code casent0005521. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by MCZ, Cambridge, MA, USA.
Strumigenys dicomas casent0499800 head 1.jpgStrumigenys dicomas casent0499800 profile 1.jpgStrumigenys dicomas casent0499800 dorsal 1.jpgStrumigenys dicomas casent0499800 label 1.jpg
Worker. Specimen code casent0499800. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Strumigenys dicomas casent0005518 head 1.jpgStrumigenys dicomas casent0005518 profile 1.jpgStrumigenys dicomas casent0005518 dorsal 1.jpgStrumigenys dicomas casent0005518 label 1.jpg
Paratype of Strumigenys dicomasWorker. Specimen code casent0005518. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Strumigenys dicomas casent0133607 head 1.jpgStrumigenys dicomas casent0133607 profile 1.jpgStrumigenys dicomas casent0133607 dorsal 1.jpgStrumigenys dicomas casent0133607 label 1.jpg
Worker. Specimen code casent0133607. Photographer Erin Prado, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Strumigenys dicomas casent0005520 head 1.jpgStrumigenys dicomas casent0005520 dorsal 1.jpgStrumigenys dicomas casent0005520 label 1.jpg
Paratype of Strumigenys dicomasWorker. Specimen code casent0005520. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.

Queen

Images from AntWeb

Strumigenys dicomas casent0137544 head 1.jpgStrumigenys dicomas casent0137544 profile 1.jpgStrumigenys dicomas casent0137544 dorsal 1.jpgStrumigenys dicomas casent0137544 label 1.jpg
Queen (alate/dealate). Specimen code casent0137544. Photographer Erin Prado, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Strumigenys dicomas casent0052908 head 1.jpgStrumigenys dicomas casent0052908 profile 1.jpgStrumigenys dicomas casent0052908 profile 2.jpgStrumigenys dicomas casent0052908 dorsal 1.jpgStrumigenys dicomas casent0052908 label 1.jpg
Queen (alate/dealate). Specimen code casent0052908. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Strumigenys dicomas casent0137196 head 1.jpgStrumigenys dicomas casent0137196 profile 1.jpgStrumigenys dicomas casent0137196 profile 2.jpgStrumigenys dicomas casent0137196 dorsal 1.jpgStrumigenys dicomas casent0137196 label 1.jpg
Queen (alate/dealate). Specimen code casent0137196. Photographer Erin Prado, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.

Male

Images from AntWeb

Strumigenys dicomas casent0135118 head 1.jpgStrumigenys dicomas casent0135118 profile 1.jpgStrumigenys dicomas casent0135118 profile 2.jpgStrumigenys dicomas casent0135118 profile 3.jpgStrumigenys dicomas casent0135118 dorsal 1.jpgStrumigenys dicomas casent0135118 label 1.jpg
Male (alate). Specimen code casent0135118. Photographer Erin Prado, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • 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

References based on Global Ant Biodiversity Informatics

  • Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
  • Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.
  • Fisher, B. 2002. Ant diversity patterns along an elevational gradient in the Reserve Speciale de Manongarivo, Madagascar. in Gautier, L. and S.M. Goodman, editors, Inventaire Florestique et Faunistique de la Reserve Speciale de Manongarivo (NW Madagascar)