Cyphomyrmex bicarinatus, Snelling, R. R. & Longino, J. T., 1992

Snelling, R. R. & Longino, J. T., 1992, Revisionary notes on the fungus-growing ants of the genus Cyphomyrmex, rimosus-group (Hymenoptera: Formicidae: Attini)., Insects of Panama and Mesoamerica: selected studies., Oxford: Oxford University Press, pp. 479-494 : 492-493

Cyphomyrmex bicarinatus , new species (Figs. 30.1, 30.10, 30.19)

Diagnosis.

A member of the salvini subgroup in which the worker is separable from that of C. salvini by the lack of a supraocular tubercle, the prominent and slender posterior mesonotal tubercle, and the presence of a pair of sharp sublateral carinae on the propodeum that terminate in spine-like processes on the declivitous face. The presence of an occipital spine, the broad, scale-like hairs, and the presence of a distinct median groove at the base of the first gastral tergum will separate C. bicarinatus from C. vorticis . The female of C. bicarinatus is separable from those of C. salvini and C. vorticis by the same cephalic and gastral features as are the workers and, in addition differs from both in having more pronounced propodeal spines. The male of C. bicarinatus is unknown.

Description

Worker holotype. Measurements: Total length 3.1 (2.9-3.1); head length 0.79 (0.7 3-0.82); head width 0.6 (0.56-0.62); mesosomal length 1.04 (0.91-1.04); metafemur length 0.86 (0.81 -0.88) mm.

Dull brownish ferruginous, carinae and tubercles darker: funiculus and legs mostly yellowish ferruginous; mandibles reddish. Integument opaque throughout, minutely granulose.

Head shape as in Fig. 30.1. Mandible subopaque and very finely longitudinally lineolate; basal tooth minute. Anterior margin of clypeus transverse or weakly emarginate in middle; parafrontal teeth prominent. Frontal area sharply, though shallowly, impressed. Frontal lobe 0.81 (0.76-0.81) times transocular distance; outer margin broadly curved, corner above parafrontal tooth narrowly and abruptly rounded; frontal carina strongly developed and attaining occipital corner and joining supraocular carina. Occipital margin deeply concave between occipital corners. Submedian carinae of vertex strong, subparallel anteriorly, posterior segment not reaching laterally to frontal carina. Supraocular tubercle absent. Occipital corner, at junction of frontal and supraocular carinae distinctly elevated, short-spiniform in lateral view. Posterior genal margin carinate to mandible base. Scape, in repose, extending beyond occipital corner by about its apical width; middle segments of funiculus a little longer than broad. Eye with about seven facets across greatest diameter; oculomandibular distance 1.00-1.25 times eye length.

Mesosoma as in Fig. 30.10. Submedian pronotal tubercles distinct; lateral tubercles short and subacute. Anterior mesonotal tubercles conical, acute; posterior pair slightly shorter, subacute to acute, compressed. Propodeum with high, compressed sublateral carina-like ridges that terminate on declivity as short, triangular teeth. Ventral margin of metafemur dilated at about basal one-third, with continuous carina from base to apex.

Petiole and post-petiole as in Fig. 30.19. Node of petiole about twice wider than long. Postero-median depression of post-petiole broad and clearly defined.

First gastral tergum with defined median, longitudinal impression that is usually completely apilose and several times longer than broad.

Pilosity flattened and scale-like, but several times longer than broad, with acute apices; narrowest on head; most hairs distinctly elevated above, but bent parallel to integument.

Female. Measurements: Total length 3.4; head length 0.82; head width 0.60; mesosoma length 1.08; metafemur length 0.86 mm.

Head as in worker except that minute ocelli are present; eye with about 12 facets across greatest diameter.

Lateral pronotal tooth prominent, subacute. Area between Mayrian furrows strongly raised on either side, deeply depressed along middle; notauli indistinct. Axilla elevated, triangular. Margins of scutellum strongly raised, posterior emargination jeep and rounded. Sublateral ridges of propodeum distinct, compressed, forming blunt, tooth like process on each side. Petiole, post-petiole, and gaster as in worker.

Tvpe material

Holotype worker: one dealate female and 45 worker paratypes: Cincinnati, c. 13oo m elev.. Magdalena Province, colombia. Feb. 1924 W. M. Mann; additional paratypes are from 2 km NW. San Pedro, 1200 m dev.. 10° 55'N 74°03'W, Magdalena, 16 Aug. 198 5 (J. Longino. Holotype and most paratypus in USNM; paratypes also in LACM, LONG, and MCZ.

Etymology. Combines the Latin prefix, bi- (two or double., with carina ridge), signifying the pair of strong propodeal ridges.

Discussion. Among those species of the rimosus group that possess the middle pair of pronotal tubercles, this can be confused only with C. salvini , the only other species with which it shares the spine-like occipital corners and scale-like pilosity. Particularly notable differences between the workers are the lack of supraocular tubercles and the strongly developed sublateral propodeal ridges in C. bicarinatus .

The pilosity is very similar to that of C. salvini but the hairs, especially on the gaster are narrower, with distinctly acute tips, and are less closely appressed to the surface. Both species differ from C. vorticis , the only other member of the subgroup, in which the hairs of the disc of the first gastral tergum are so closely appressed against the segment that they are not visible in profile. Other differences between C. vorticis and the other two species are set forth in the key.