Cyphomyrmex laevigatus Weber

Kempf, W. W., 1966, A revision of the Neotropical fungus-growing ants of the genus Cyphomyrmex Mayr. Part II. Group of rimosus (Spinola) (Hym. Formicidae)., Studia Entomologica (N. S.) 8, pp. 161-200: 178-179

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Cyphomyrmex laevigatus Weber


6. Cyphomyrmex laevigatus Weber   HNS  

(Figs. 4, 26, 32, 41)

Cyphomyrmex (Cyphomannia) laevigatus Weber   HNS   , 1938: 184-5, figs. 20-1 (Worker; Bolivia: lower Rio Madidi). - Weber, 1940: 408 (Worker; key).

Cyphomyrmex laevigatus   HNS   ?: Kempf, 1961: 518 (Worker; Surinam: Dirkshoop).

Cyphomyrmex laevigatus   HNS   : Kempf, 1962: 29-30. - Kempf, 1964: 4.

Types. - 12 workers from a single nest series; 4 workers (lectotype and paratypes) examined (NAW, MCZ).

Worker (lectotype). - Total length 3.5 (3.3-3.7) mm; head length 0.91 (0.85-0.96) mm; head width 0.88 (0.85-0.96) mm; thorax length 1.20 (1.07-1.23) mm; hind femur length 0.91 (0.85-0.94) mm. Rather close to bicornis   HNS   with the following differential characters:

Head (Fig. 4) dorsally with vestigial longitudinal rugae. Clypeus with a small to vestigial accessory tooth mesad of anterolateral one. Auriculate occipital lobes slightly less projecting caudad. Antennal scape rather abruptly thickened after basal third. Eyes with about 9 facets across greatest diameter.

Thorax (Fig. 26) completely unarmed on dorsum. Pronotal disc laterally rather sharply carinate. Mesoepinotal junction not deeply impressed, but with a distinct mesoepinotal suture. Fore femora dorso-apically with a short longitudinal, lamellate carinule. Hind femora (Fig. 41) as in bicornis   HNS   , not longer than maximum head width.

Pedicel shown in Figs. 26 and 32. Petiole much shorter and broader, likewise without dorsal ridges. Postpetiole with a weak impression laterally, discad of posterior border; the latter vestigially notched in the middle.

Hairs minute, fine, strictly appressed, less conspicuous than in bicornis   HNS   .

Female and male unknown.

Specimens examined: 11 workers, as follows: Bolivia: lower Madidi River, January 1922, W. M. Mann leg. 4 workers (lectotype: NAW; paratypes: MCZ). - Surinam: Dirkshoop, May 1959, primary forest on sand, J. van der Drift leg. 7 workers (WWK and van der Drift collections).

Discussion. - The Surinam specimens fully agree with the types from northwestern Bolivia. The variation in measurements was already given above in the differential diagnosis. C. laevigatus   HNS   seems to be a denizen of the soil in woodland. The Surinam catches came from primary forest and were secured from pitfall traps and desiccated soil samples.

As shown in previous publications (Kempf, 1962, 1964), laevigatus   HNS   is not sufficiently distinct to be placed into a separate subgenus, as proposed by its author (Weber, 1938). It is rather similar to bicornis   HNS   and doubtless still an orthodox member of the rimosus-group.