Cyphomyrmex kirbyi Mayr

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: 179-181

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Cyphomyrmex kirbyi Mayr


7. Cyphomyrmex kirbyi Mayr  HNS 

(Figs. 11, 17, 27, 42)

Cyphomyrmex kirbyi Mayr  HNS  , 1887: 557 (Worker; Colombia). - Santschi, 1921: 97-98 (Female: Ecuador: Guayaquil). - Weber, 1940: 408. (Worker; key).

Cyphomyrmex difformis Mayr  HNS  , 1S70 (nec Fr. Smith, 1858): 372 (Colombia).

Cyphomyrmex deformis Forel  HNS  , 1884 (nec Roger, 1863): 368.

Types. - 11 workers - lectotype and paratypes - from N. Grenada (= Colombia), received on loan from the Mayr collection (NHMW). Mayr, foregoing a detailed description, has proposed this species by merely presenting a few differential characters. Hence I give the following diagnosis, based on the type series.

Worker (lectotype). - Total length 3.6 (3.5-3.7) mm; head length 0.84 (0.80-0.85) mm; head width 0.77 (0.72-0.80) mm; thorax length 1.25 (1.14-1.25) mm; hind femur length 1.07 (0.99-1.09) mm. Dark reddish brown; mandibles, funiculus and legs a bit lighter, without reddish hues. Integument opaque throughout, finely, densely and indistinctly punctate-granulate. Scape reticulate-rugose. Front with a few fine, longitudinal rugulae.

Head as shown in Fig. 11. Mandibles finely striolatepunctate, subopaque; chewing border with 5 teeth, a larger diastema between 2nd and 3rd basal tooth, as in rimosus  HNS  and allies. Anterior border of clypeus not excised in the middle; tooth near origin of frontal lobes obsolescent. Frontal area impressed, hairless. Frontal lobes not semicircular, but somewhat angular, with an acutely rounded corner projecting in front and a more bluntly rounded corner projecting laterad. Posterior prolongation of frontal carinae sigmoidal. Carinae of vertex present, subparallel. Preocular carina curving mesad above eye. There is no postocular carina between posterior border of eye and occipital corner. Supraocular tubercle obtuse and low. Dentate occipital corner little projecting. Occipital border gently excised, a bit more deeply concave between carinae of vertex. Inferior border of cheeks marginate in its entire length. Scape in repose exceeding the occipital corner by nearly twice its maximum thickness. Funicular segments II-IV distinctly longer than broad.

Thorax as shown in Fig. 17. Midpronotal tubercles absent, lateral ones well developed, each sending out foreward an illdefined carinule separating the dorsal face from the lateral face of pronotum. Inferior pronotal corner rather obtuse and not dentate. Mesonotum with two pairs of parallel and subcontinuous longitudinal ridges, the anterior pair in profile dentiform, the posterior pair blunter. Mesoepinotal constriction deep and broad. Basal face of epinotum with a pair of sharp longitudinal ridges, their anterior and posterior ends subdentate in profile; laterally, on sides of thorax, another weaker and lower carina, which bears the epinotal spiracle. Hind femora (Fig. 42) not conspicuously broadened nor angulate beneath.

Pedicel as shown in Figs. 17 and 27. Petiole depressed; node not strikingly transverse but only little broader than long.

Postpetiole with a deep postero-median impression, its lateral border practically immarginate.

Pilosity decumbent to appressed, not scale-like yet glistening, golden; rather long and conspicuous on gaster. Tip of tibiae and gaster with a few standing hairs.

Female. - This caste was made known by Santschi (1921) who gave it the following description:

"Long. 2,7 mm. Differe de rimosus Mayr  HNS  (sic!), par sa tete un peu plus longue, le bord postoculaire non dente. L'angle de l'epistome forme un petit lobe arrondi (lobe anguleux chez rimosus  HNS  ). Le bord anterieur plus arque, les aretes frontales moins relevees; sur un plan plus egal a celui du front. Le sillon median du mesonotum beaucoup moins profond. Les dents de l'epinotum plus Iongues. Ailes un peu plus claires. Pilosite squameuse, surtout sur le gastre, qui est en outre pruineux. - Equateur: Guayaquil (Rosenberg, 1904) ouvriere et femelle. Museum de Paris. - Ces exemplaires avaient ete determines sous le nom de C. rimosus Mayr  HNS  , par E. Andre, mais ils se rapportent bien rhieux a la description de C. kirbyi  HNS  , que je ne connais pas en nature".

I am afraid that this description is not very helpful for the recognition of isolated females. It is even doubtful whether Santschi's specimens really belong to the present species.

Male unknown.

Discussion. - So far, except for the aforementioned Ecuador specimens, kirbyi  HNS  is still known only from the types, hailing from an unknown locality in Colombia.

The paratype workers fully agree with the foregoing description. Their variation as regards the critical measurements was already given above in parentheses.

C. kirbyi  HNS  doubtless belongs to the rimosus-group, and differs from rimosus  HNS  in the shape of the frontal lobes (Fig. 11), absence of conspicuous parafrontal teeth on clypeus, elongate funicular segments II-IV, rather obtusely angulate infrapronotal corner, lack of midpronotal tubercles, sharper and lower meso- and epinotal ridges which never form distinctly conical tubercles, shape of hind femora which are not angulate beneath, significantly less transverse petiole, body hairs which are not squamate but simple, longer and more conspicuous.

The very long scapes and the thoracic profile reminds of vorticis  HNS  and salvini  HNS  , but kirbyi  HNS  lacks the midpronotal tubercles, the prominent spine-like occipital lobes, the ventral lobe or angle on basal third of hind femora.

The Mexican dentatus  HNS  and Brazilian peltatus  HNS  agree with kirbyi  HNS  in the absence of midpronotal tubercles, but differ in smaller size, more thick-set body, different shape of head, thorax, pedicel and hind femora, as can be readily seen by a comparison of the respective figures.