Trachymyrmex zeteki Weber

Mayhé-Nunes, Antonio J. & Brandão, Roberto F., 2007, Revisionary studies on the attine ant genus Trachymyrmex Forel. Part 3: The Jamaicensis group (Hymenoptera: Formicidae), Zootaxa 1444, pp. 1-21 : 16-20

Trachymyrmex zeteki Weber

( Figs. 23–28 , 30)

Trachymyrmex zeteki Weber, 1940: 422 (worker). Kempf, 1972: 254 (catalog). Weber, 1972: 12 (dorsal female drawing). Bolton, 1995: 421 (catalog).

Trachymyrmex balboai Weber, 1940: 424 (worker). Weber, 1958: 55 (synonymy). [Type material: one “cotype” worker, examined]

Worker measurements (n = 3). TL 5.0 (4.7–5.2); DHL 1.44 (1.40–1.48); HW 1.44 (1.42–1.48); IFW 0.83 (0.80–0.86); ScL 1.00 (0.97–1.02); HWL 0.85 (0.77–0.92); MeL 1.92 (1.88–1.98); PL 0.44 (0.38–0.49); PPL 0.42; GL 1,33 (1.26–1.42); HfL 2.01 (1.97–2.05).

Worker description: Ferruginous. Integument opaque and finely granulose. Pilosity: bristly spatulate dark hairs with lighter tips, confined to body projections; short, strongly curved and hook-like hairs in other parts of the body.

Head in full face view ( Fig. 23 ) as long as broad (DCI average 100; 99–101). Outer border of mandible feebly sinuous; chewing border with 8 teeth, with a diastema between the second and third teeth, the last six approximately of the same size, smaller than apical and sub-apical teeth. Clypeus median apron without projections. Frontal area impressed. Frontal lobe semicircular, moderately expanded (FLI average 57; 56–58), with weakly crenate free border and one prominent denticle on the antero-lateral border. Frontal carina marked, moderately diverging caudad, reaching the antennal scrobe posterior end in a single tooth at the vertexal margin; preocular carina posteriorly ending in one multituberculated and stout tubercle, with the tip outwards directed near the posterior margin of head. Occipital spine almost as long as preocular carina projection. Supraocular projection tuberculiform. Inferior corner of occiput, in side view, with a minute tooth. Eye faintly convex, only its anterior half surpassing the lateral border of head; 11 facets in a row across the greatest diameter. Antennal scape short, when lodged in the scrobe not surpassing the tip of the preocular carina projection; gradually thickened towards apex, covered with small piligerous tubercles.

Mesosoma ( Figs. 24, 25 ). Pronotal dorsum marginate in front and on sides; antero-inferior corner with a small triangular and acute flattened spine; inferior margin weakly crenulated; median pronotal tooth with bifid tip, projected bellow the tip of the longer lateral pronotal spines, which point obliquely upwards from the pronotum, in frontal view. Anterior pair of mesonotal spines almost as long and stout as the lateral pronotal projections, directed upwards; the second pair smaller, but spine-like and longer than the tooth-like third pair. Anterior margin of katepisternun smooth, without a projecting tooth. Metanotal constriction very impressed. Basal face of propodeum laterally marginated by a row of 3–4 denticles on each side; propodeal spines longer than the distance between their inner bases. Hind femora a little longer than mesosoma length.

Waist and gaster ( Fig. 26 ). Dorsum of petiolar node with two pairs of minute spines, the sides subparallel in dorsal view, with a series of lateral denticles. Postpetiole almost as long as broad in dorsal view, and impressed dorsally, with straight postero-dorsal border; sternum without sagital keel. Gaster, when seen from above, suboval. Tergum I with straight lateral faces separated from the dorsal face by a longitudinal row of piligerous tubercles; anterior two thirds of gaster dorsum with three piligerous shallow longitudinal furrows, separated by a pair of tubercles rows. Sternum I without an anterior sagital keel.

Gyne (undescribed; Figs. 27, 28 ): TL 6.9; DHL 1.74; HW 1.63; IFW 1.02; ScL 1.14; HWL 1.05; MeL 2.43; PL 0.68; PPL 0.57; GL 2.17; HfL 2.20. Resembling the worker with the usual caste differences. The median anterior ocellus without a down curved ridge above, and the two lateral ones partially concealed by the longitudinal carinae of vertex. Pronotum with a pair of strong and acute scapular spines on each side, directed out and forwards, the inferior ones pointed down and forwards. Mesoscutum surmounted by conspicuous tubercles, but without notable dorsal projections, superficially impressed on posterior region, with a median notch in the middle of anterior margin in dorsal view. Shallowly impressed parapses delimited by the conspicuous parapsidial furrows; dorsum of mesothoracic paraptera more or less impressed, oblique in relation to scutellum dorsum in side view, with a narrow median portion when seen from above; scutellum ending in a pair of moderately stout and acute spines, directed backwards, with the sides converging obliquely inwards; metathoracic paraptera concealed by the scutellum in dorsal view; propodeal spiracle orifices on a tubercular projection. Two massive and acute spines on propodeum, longer than pronotal ones. Petiolar dorsum with two pairs of minute teeth near the anterior and posterior margins. First gastric tergite with a longitudinal ridge on each side; disk with two longitudinal series of small piligerous tubercles, absent in the middle of the segment. Wings unknown.

Male: Unknown.

FIGURES 29–30. Distribution map of Trachymyrmex of the Jamaicensis species group. 29. Greater Antilles and part of Florida, USA. 30. Parts of Central and South America.

Syntype worker: PANAMA Canal Zone, Barro Colorado Island, 25.vi.1938, N.A. Weber leg., 1 worker (“cotype” # 59827 deposited in USNM).

Material examined: COSTA RICA: Alajuela, Rio Peñas Blancas [10o 19´N, 84o 43´W], 800m, 22.v.1987, J. Longino#1684-s “wet forest, worker on ground, at night,” specimen code INBIOCRI001284172, 1 worker ( JTLC); Heredia, Est. Biol. La Selva, 50–150m [10o 26´N, 84o 01´W], 27.iv. 1999, E. Sarnat, specimen code INBIOCRI002739914, 1 worker ( JTLC); ibidem, specimen code INBIOCRI002739913, 1 worker JTLC). ECUADOR: Pichincha, Centr. Cient. Rio Palenque, S. Sandoval (several dates) 40 workers, 5 dealate gynes ( MZSP, CECL, QCAZ, USNM). PANAMA Canal Zone, Barro Colorado Island, 13.vi.1958, N.A. Weber leg. (3 syntypes workers of T. balboai deposited in MZSP); ibidem, Feb–Mar; Jul–Aug. 1944, J.A.S. Zetek leg., respectively 2 and 1 worker ( MZSP); ibidem, 15. ii. 1960, N.A. Weber col. 2 workers ( MZSP).

Comments: See comments for T. atlanticus . Trachymyrmex zeteki females share with T. isthmicus and T. ixyodus projecting teeth at the anterior margin of the frontal lobes, but differ from females of T. ixyodus by the presence of a single midpronotal denticle, while females of T. isthmicus show double midpronotal denticles. Weber (1940) found a nest at the slope of a hill in the back of the Barro Colorado island laboratory in dense shade, with a single chamber about 67mm deep in the soil, horizontally elliptical, 42 X 80mm. In 1972, Weber described briefly the population and male flights in the laboratory.

Figures

FIGURES 23 – 26. Scanning electron micrograph of Trachymyrmex zeteki, worker from Panama, Canal Zone, Barro Colorado. 23. Head in frontal view; scale bar = 250 μm. 24. Mesosoma in lateral view; scale bar = 250 μm. 25. Mesosoma in dorsal view; scale bar = 250 μm. 26. Waist and gaster in dorsal view; scale bar = 500 μm.

FIGURES 27 – 28. Gynes of Trachymyrmex zeteki from Ecuador, Pichincha, Rio Palenque. 27. Head in frontal view. 28. Mesosoma and metasoma in lateral view. Scale bar = 1000 μm.