Strumigenys tetragnatha

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Strumigenys tetragnatha
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. tetragnatha
Binomial name
Strumigenys tetragnatha
(Taylor, 1966)

Strumigenys tetragnatha casent0217148 p 1 high.jpg

Strumigenys tetragnatha casent0217148 d 1 high.jpg

Specimen Labels

A widely ranging litter species that has been collected from numerous forest habitats.

Identification

A member of the Strumigenys tetragnatha-group. The only known relative of tetragnatha is Strumigenys africana; the two are separated as follows in the worker.

africana tetragnatha
Larger species with shorter antennal scapes, HW 0.70, SI 43. Smaller species with longer antennal scapes, HW 0.49-0.58, SI 47-51.
Lateral margins of head in full-face view with 3 pairs of projecting flagellate hairs. Lateral margins of head in full-face view without flagellate hairs.
Appressed cephalic pilosity longer posteriorly than anteriorly; much longer than the clypeal pubescence. Appressed cephalic pilosity very short, of approximately equal length everywhere; no longer than the clypeal pubescence.
Postpetiole and first gastral tergite with numerous long fine flagellate hairs. Postpetiole and first gastral tergite with simple sparse short straight hairs.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Angola (type locality), Cameroun, Gabon, Ghana, Ivory Coast, Kenya.


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.

  • tetragnatha. Codiomyrmex tetragnathus Taylor, 1966a: 225, figs. 1, 2 (w.) ANGOLA. Combination in Glamyromyrmex: Bolton, 1983: 323; in Pyramica: Bolton, 1999: 1672; in Strumigenys: Baroni Urbani & De Andrade, 2007: 129. See also: Bolton, 2000: 330.

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 2.4-2.8, HL 0.60-0.70, HW 0.49-0.58, CI 79-83, ML 0.14-0.16, MI 22-24, SL 0.25-0.28, SI 47-51, PW 0.28-0.34, AL 0.58-0.62 (4 measured).

Mandibles with a broad basal lamella followed by a row of 5 large triangular teeth which are slightly recurved and evenly spaced on the strongly down curving arch of the apical margin. Distal to this tooth row is a series of 3 denticles which share a common base on a low process. In profile the mandibles rapidly increasing in width from base to apex, the upper and lower borders strongly divergent, the former arching up above the level of the anterior clypeal margin, the latter shallowly concave and downcurved; apical margin as seen in profile strongly arched-convex. With the head in full-face view the anterior clypeal margin with a median indentation, the clypeus broad but the lateral free margins not extended into lobes and noticeably narrower than the sides of the head behind the clypeus. General shape of head in profile and full-face views as described for africanus. Antennal scapes short (SI 47-51) and feebly clavate, not bent near the base, with the leading edge more or less evenly convex and lacking projecting hairs. Clypeal dorsum with minute appressed pubescence which is directed anteriorly. Dorsum of head with anteriorly or anteromedially directed minute appressed hairs which are approximately the same length everywhere on the dorsum and no longer than the clypeal pubescence. Lateral margins of head without flagellate hairs. Clypeus smooth. Dorsum of head with minute scattered pits from which the hairs arise, otherwise unsculptured except for a feeble superficial shagreening in places. Sides of alitrunk sharply laterally marginate throughout their length, most strongly so on the pronotum where the marginations are prominent and overhang the sides. Pronotum also marginate anteriorly and with a median longitudinal ridge or carina dorsally. Dorsum of mesonotum separated from the short propodeal dorsum by a low transverse crest; metanotal groove absent. Propodeal teeth very broad basally, rapidly tapering apically and with the extreme apices suddenly upcurved. Infradental lamellae much narrower than the propodeal teeth, the latter with more than half their length standing free of the lamellae. Sides of alitrunk unsculptured except for the punctate mesopleuron and some weak peripheral sculpture round the margins of the segments. Dorsal alitrunk with some superficial rugular vestiges on the pronotum and mesonotum beside the median carina. Lateral margins of alitrunk with two pairs of long simple hairs, the first pair at the pronotal humeri, the second pair just in front of the transverse crest that separates mesonotum from propodeum. Dorsal alitrunk otherwise with only sparse appressed simple hairs which are very short. Spongiform ventral appendage of petiole peduncle massively developed and curtain-like, about as deep as the node is high. Other spongiform material on petiole reduced to short aliform prominences situated lateroventrally when the node is viewed from above. Petiole node sparsely rugulose, disc of postpetiole finely densely and quite regularly longitudinally costulate. Lateral spongiform appendages of petiole narrow in dorsal view, broadest posterolaterally. Anterior face of the postpetiolar disc with a narrow bordering lamella, the posterior margin bordered by a convex rim which abuts a similar but concave rim bordering the base of the first gastral tergite. First gastral tergite lamellate basally, not spongiform, with numerous strong basigastral costulae and with many secondary costulae arising between them on the body of the tergite. First gastral sternite without a basal spongiform pad. Petiole, postpetiole and first gastral tergite with scattered short straight simple hairs. Colour blackish brown to black.

Type Material

Bolton (1983) - Holotype worker, ANGOLA: Dundo, Route Turismo, approx 7"02'S, 20051'E, gallery forest, 28.iii.1962, no. 16888, R. Luachimo, ‘berlesate by native collector’ (Museum of Comparative Zoology) [examined].

References

  • 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). Bull. Br. Mus. (Nat. Hist.) Entomol. 46:267-416. PDF (page 323, Combination in Glamyromyrmex, redescription of worker)
  • Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). J. Nat. Hist. 3 33: 1639-1689 (page 1672, combination in Pyramica)
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 330, figs. 215, 237 redescription of worker)
  • Taylor, R. W. 1966a [1965]. A second African species of the dacetine ant genus Codiomyrmex. Psyche (Camb.) 72: 225-228 (page 225, figs. 1, 2 worker described)