Strumigenys tacta

A widely distributed forest species that has been found in litter-samples.

Identification
A member of the Strumigenys baudueri-group.

Bolton (2000) – Antenna with 4 segments. Dorsolateral margin of head with 3 pairs of laterally projecting flagellate hairs; cephalic dorsum near occipital margin with a vertically directed pair of flagellate hairs. Pronotum sharply marginate anteriorly and laterally, the dorsum smooth and with a longitudinal median carina.

Bolton (1983) - Of the seven known Afrotropical species with 4-segmented antennae only two, tacta and Strumigenys marginata, have the pronotum sharply marginate laterally and equipped medially with a longitudinal carina. These two are separated by the shape and pilosity of the clypeus as indicated in the key, and by the characters noted in the species-group diagnoses. Characters separating tacta and Strumigenys vodensa can be separated as follows:

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Democratic Republic of Congo, Gabon, Ghana, Ivory Coast, Uganda.

Nomenclature

 *  tacta. Smithistruma tacta Bolton, 1983: 317 (w.) IVORY COAST. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 128. See also: Bolton, 2000: 295.

Worker
Holotype. TL 1.7, HL 0.46, HW 0.31, CI 67, ML 0.07, MI 15, SL 0.20, SI 65, PW 0.20, AL 0.46.

Principal dental row of mandible with 7 teeth followed by 4 minute denticles and a small apical tooth. Basal lamella of mandible a long low rounded lobe which is no higher than the basal most tooth; without a diastema between basal lamella and the basalmost tooth. In full-face view the clypeus with shallowly convex sides which are evenly convergent anteriorly and with a strongly convex anterior margin which is narrowly rounded medially. The anterior margin on each side of the midpoint forms a single evenly convex line which is continuous with the lateral margins, without trace of an anterolateral angle. Outer margins of the fully closed mandibles forming a more or less continuous line with the outer margins of the clypeus in full-face view. Dorsum of clypeus densely clothed with short spatulate hairs which are curved, decumbent and directed anteriorly. Lateral and anterior clypeal margins similarly densely clothed. Dorsum of head with decumbent curved fine hairs, those in front of the vertex directed towards the midline, the remainder directed towards the highest point of the vertex. Upper scrobe margins with a number of fine curved hairs similar to those on the dorsum of the head, and also with three pairs of long laterally projecting flagellate hairs; the cephalic dorsum near the occipital margin with another pair of flagellate hairs which are directed vertically. Antennae with 4 segments; the scape slender and only very weakly curved basally, not flattened. Leading edge of scape without a freely projecting row of strong hairs, only with fine curved pubescence which is subdecumbent to decumbent. Eyes small, the maximum diameter 0.06 X HW. Cephalic dorsum reticulate-punctate everywhere, clypeal dorsum more finely punctate but the sculpture partially concealed by the dense pilosity. Pronotum strongly and sharply marginate anteriorly and laterally, the pronotal dorsum with a strong median longitudinal ridge or carina which does not extend onto the mesonotum. Sides of mesonotum angular, of propodeum sharply marginate. Alitrunk in dorsal view with a transverse straight line between the mesonotum and propodeum. Pronotal humeri each with a long laterally directed flagellate hair. Vertically directed flagellate hairs present in pairs on dorsum at midlength of pronotal lateral margination and posterolaterally on mesonotum. Pilosity of dorsal alitrunk otherwise of fine simple strongly curved hairs on the pronotum and mesonotum. Fine simple hairs, some of which may be looped apically, present on dorsal surfaces of petiole, postpetiole and first gastral tergite. Sides of alitrunk unsculptured, the propodeal teeth lamelliform and continuous with the infradental lamellae. Pronotal dorsum unsculptured apart from the strong median carina. Mesonotum reticulate-punctate. Propodeal dorsum and declivity glassy smooth. Dorsum of petiole node finely punctate, postpetiole glassy smooth. First gastral tergite unsculptured except for the basigastral costulae. Spongiform appendages of pedicel segments strongly developed in profile. Petiole node in dorsal view with a broad strip of spongiform material posteriorly. Anterior margin of postpetiole with a narrow spongiform strip, the posterior margin with a much broader band of spongiform tissue which is indented medially. Base of first gastral tergite with a spongiform to lamellar strip which is concave medially. Colour yellow to yellowish brown.

Paratypes. TL 1.7-1.8, HL 0.42-0.46, HW 0.29-0.31, CI 65-70, ML 0.06-0.08, MI 14-17, SL 0.18-0.20, SI 61-67, PW 0.19-0.22, AL 0.44-0.48 (10 measured). As holotype.

Type Material
Holotype worker, Ivory Coast: Droplieu, 1O.x.1980 (Y. Mahnert & J.-L. Perret). Paratypes. Ivory Coast: 2 workers with same data as holotype; 7 workers, Monogaga, 24.x.1980 (Y. Mahnert & J.-L. Perret); 1 worker, Man, Mt Tonkoui, 900 m, 13.x.1980 (Y. Mahnert & J.-L. Perret) (MHNG; ; ).

References based on Global Ant Biodiversity Informatics

 * Belshaw R., and B. Bolton. 1994. A survey of the leaf litter ant fauna in Ghana, West Africa (Hymenoptera: Formicidae). Journal of Hymenoptera Research 3: 5-16.
 * Belshaw R., and B. Bolton. 1994. A survey of the leaf litter ant fauna in Ghana, West Africa (Hymenoptera: Formicidae). Journal of Hymenoptera Research. 3: 5-16.
 * Bolton B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology 46: 267-416.
 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * Braet Y., and B. Taylor. 2008. Mission entomologique au Parc National de Pongara (Gabon). Bilan des Formicidae (Hymenoptera) recoltes. Bulletin S. R. B. E./K.B.V.E. 144: 157-169.
 * IZIKO South Africa Museum Collection