Strumigenys transversa

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Strumigenys transversa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. transversa
Binomial name
Strumigenys transversa
Santschi, 1913

Strumigenys transversa casent0280699 p 1 high.jpg

Strumigenys transversa casent0280699 d 1 high.jpg

Specimen Labels

Known from a small number of collections. The two records with collection details show both are from forest-litter samples, with one adding this was a rainforest.

Identification

Bolton (2000) - The only member of the Strumigenys transversa-group. Apart from the shape of the mandibular basal lamella this species would fall easily into the emarginata-group. Its transverse anterior clypeal margin is easily visible but this feature occurs in a few emarginata-group species (Strumigenys hensekta and some members of the emarginata-complex).

Bolton (1983) - This species is peripheral to the emarginata-group but is isolated by its uniquely shaped mandibular basal lamella and broad infradentallamellae on the propodeum.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Gabon, South Africa (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Nomenclature

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

  • transversa. Strumigenys (Trichoscapa) transversa Santschi, 1913b: 258 (diagnosis in key) (w.) SOUTH AFRICA. Santschi, 1914e: 31 (w.). Combination in S. (Cephaloxys): Wheeler, W.M. 1922a: 920; Emery, 1924d: 324; in Smithistruma: Brown, 1948e: 105; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 129. See also: Brown, 1953g: 127; Bolton, 1983: 297; Bolton, 2000: 334.

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

Description

Worker

Bolton (1983) - TL 2.2-2.4, HL 0.62-0.66, HW 0.42-0.46, CI 68-71, ML 0.12-0.13, MI 19-20, SL 0.27-0.28, SI 60-64, PW 0.26-0.28, AL 0.58-0.62 (5 measured).

Basal lamella of mandible an elongate high broadly rounded lobe whose length along the base is approximately the same as the length of the masticatory margin occupied by the principal row of 5 teeth, and which is clearly visible even when the mandibles are closed. Height of the basal lamella equal to that of the longest of the teeth. Principal row of 5 teeth followed distally by 2 slightly smaller teeth and 4 minute denticles before the small apical tooth. Anterior clypeal margin transverse to very shallowly evenly convex, equipped with 8 scale-like hairs which project forwards over the mandibles and which are usually slightly curved medially. Lateral margins of clypeus very slightly convergent anteriorly and with an unbroken series of long broad spatulate to spoon-shaped hairs which project freely and are curved anteriorly. Dorsum of clypeus and cephalic dorsum with numerous scale-like to spoon-shaped anteriorly curved short hairs; those on the clypeus smaller than those on the cephalic dorsum. Upper scrobe margins and sides of the occipital lobes with an unbroken sequence of sharply anteriorly curved spoon-shaped hairs which are closely applied to the surface. Flagellate hairs absent. Antennal scape narrow basally, bent at about the basal third and broadest just beyond the bend. Leading edge of scape with a projecting row of strong spatulate to spoon-shaped hairs, the dorsum of the scape also with spatulate hairs present. Eyes relatively large, maximum diameter 0.18 X HW, greater than the maximum width of the scape. Entire dorsum of head finely and densely reticulate-punctate. Pronotum not marginate laterally and without a median longitudinal ridge or carina dorsally. Flagellate hairs absent. Metanotal groove not impressed and propodeal teeth subtended by a broad and conspicuous infradental lamella. Dorsal alitrunk with narrowly spatulate short hairs, most of which are reclinate but a few of which may be subdecumbent. Petiole and postpetiole with similar pilosity and also with elongate quite stout simple hairs which are directed posteriorly. First gastral tergite with a transverse row of 4 erect hairs basally, grouped in pairs on each side of a central broad gap. Remainder of first tergite hairless except for a widely separated pair close to the apical margin. Pleurae of alitrunk mostly smooth, usually with some punctures basally and on upper anterior portion of the mesopleuron. Pronotal and mesonotal dorsa finely and densely reticulate-punctate but dorsum of propodeum mostly or entirely smooth; usually with some laterally situated punctures and with punctures on the declivity between the propodeal teeth. Dorsum of petiole node distinctly broader than long, sometimes indented medially; un sculptured or at most with superficial vestiges of punctate sculpture. Post petiole smooth and shining. First gastral tergite unsculptured except for the basigastral costulae, which radiate from each side of a smooth median area. Spongiform appendages of pedicel segments strongly developed in profile. In dorsal view the petiole node with a broad posterior strip; the anterior margin of the postpetiole with a narrow strip, the posterior margin bordered by a spongiform strip which is broad posterolaterally but rapidly narrowing medially, very narrow or interrupted centrally where the postpetiole itself is indented. Base of first gastral tergite with a transverse strip which has its anterior free margin concave medially and convex at the sides where the costulae arise. Colour dark brown to blackish brown.

Bolton (2000) - TL 2.2-2.4, HL 0.60-0.66, HW 0.42-0.46, CI 68-74, ML 0.11-0.13, MI 18-20, SL 0.26-0.29, SI 60-66, PW 0.25-0.29, AL 0.58-0.62 (10 measured).

Type Material

(diagnosis in key) Holotype worker, SOUTH AFRICA: Natal (not in Naturhistorisches Museum, Basel; presumed lost). As the holotype of this species has not been found it is necessary to rely on the inadequate descriptions presented by Santschi (1913a; 1914c). Accordingly I attach the name transversa to four short series from Natal and Cape Province in South Africa which match the available descriptions tolerably well.

References

  • Arnold, G. 1917. A monograph of the Formicidae of South Africa. Part III. Myrmicinae. Ann. S. Afr. Mus. 14: 271-402 (page 380, redescription of worker)
  • Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria” 99: 1-191.
  • Bolton, B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology. 46:267-416. PDF (page 297, redescription of worker)
  • Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). J. Nat. Hist. 3 33: 1639-1689 (page 1673, combination in Pyramica)
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 334, figs. 218, 240 redescription of worker)
  • Brown, W. L., Jr. 1948e. A preliminary generic revision of the higher Dacetini (Hymenoptera: Formicidae). Trans. Am. Entomol. Soc. 74: 101-129 (page 105, combination in Smithistruma (Smithistruma) )
  • Brown, W. L., Jr. 1953g. Revisionary studies in the ant tribe Dacetini. Am. Midl. Nat. 50: 1-137 (page 127, redescription of worker)
  • Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 324, combination in Strumigenys (Cephaloxys), catalogue)
  • Santschi, F. 1913b. Clé analytique des fourmis africaines du genre Strumigenys Sm. (Hym.). Bull. Soc. Entomol. Fr. 1913: 257-259 (page 258, worker described)
  • Santschi, F. 1914e. Meddelanden från Göteborgs Musei Zoologiska Afdelning. 3. Fourmis du Natal et du Zoulouland récoltées par le Dr. I. Trägårdh. Göteb. K. Vetensk. Vitterh. Samh. Handl. 15: 1-44 (page 31, redescription of worker)
  • Wheeler, W. M. 1922j. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bull. Am. Mus. Nat. Hist. 45: 711-1004 (page 920, combination in Strumigenys (Cephaloxys))