Cryptomyrmex

The two species in this genus are known from a small number of workers and a single queen. Nothing is known about the biology of .

Identification
Fernández (2004) - This genus is created on the basis of two species from Brazil and Paraguay. Among its distinctive characteristics are mandibles with four teeth on the masticatory margin, a low tooth in the basal margin, and petiole with a long, low node. The tooth of the basal margin is lower that in Adelomyrmex, and is not accompanied by a notch as in that genus. An important characteristic is the head profile in frontal view, in which the anterior half (between the mandibular base and more or less the level of the eye) is slightly concave, and the posterior half is slightly convex. No other species in the similar group of three closely allied genera (Adelomyrmex, Baracidris and Cryptomyrmex) shares this head profile and helps separate Cryptomyrmex as a distinct genus. The potential of this character still needs examination in the context of the myrmicine ants. Petiole shape also separates Cryptomyrmex from the other two species but this character may be plesiomorphic as it present in Hylomyrma. The eyes are normally visible stereoscopically, but not in SEM images, suggesting that these are dark spots beneath the tegument or slightly developed on the tegument surface. This trait also represents a potential synapomorphy for the genus. These degenerate eyes might be associated with the subterranean habit of these ants, besides which nothing is known of the biology of the genus.

A generic group consisting of Cryptomyrmex, Adelomyrmex and Baracidris shares the following characters: With characters of solenopsidine tribe group (Bolton, 2003:57). Mandibles with four to seven teeth in the masticatory border (Fig. 4). Basal margin of mandibles simple to armed. Internal side of mandibles with a row of 2-3 to 5-6 hairs modified as lamelliform setae. Clypeus with median longitudinal plate, ridge or strip raised (Fig. 3). A median clypeal seta usually present. Palpal formula 2,2 or less. Antennae 12 segmented, with club 2-segmented. Propodeum angulated or armed with teeth. U-shaped sulcus in the basalmost portion of the first tergum. Monomorphic.

These three genera can be separated using the following key:

1

 * Mandibles with four teeth in the masticatory border; frontal area lacking; petiolar node low; Brazil and Paraguay . . . . . Cryptomyrmex


 * Mandibles with 5-7 teeth in the masticatory border; frontal area present, reduced; petiolar node high (Fig. 2) . . . . . 2

2
return to couplet #1
 * Clypeal lateral teeth present; basal margin of mandible with teeth and notch; hypostomal teeth present, usually small; Neotropics, New Guinea, Fiji, Samoa and New Caledonia . . . . . Adelomyrmex


 * Clypeal lateral teeth absent; basal margin of mandible without teeth; hypostomal bridge without teeth; Africa . . . . . Baracidris

Castes
Males have yet to be collected for this genus.

Nomenclature

 *  CRYPTOMYRMEX [Myrmicinae: Adelomyrmecini]
 * Cryptomyrmex Fernández, 2004b: 328. Type-species: Adelomyrmex longinodus, by original designation.

Worker
Head with convex posterior and evenly rounded corners. Hypostomal bridge strong and evenly developed; very much distinct from head venter. Hypostomal teeth absent. Sides of head slightly concave before the eyes, slightly convex past eyes. Mandibles with 4 teeth decreasing in size from the apical teeth, the antepenultime (subbasal) smallest. Mandibles with distinct tooth in their basal margin, at midlength, not followed by a notch. Maxillary palpomere sub cylindrical and the labial palps geniculate. Eyes lenses absent, although the pigments are clearly visible under the reflective light, but not under the SEM picture, or poorly developed (Fig. 7). Clypeus short, elevated in the middle as a narrow stripe, pointed and fused with frontal carinae. Anterior margin of the clypeus without teeth, although with feebly projections instead. Dorsal view of thorax as in figure 7. Propodeum spiracle relatively large, its orifice circular and situated just above the midlenght of the sclerite; propodeum dorsum straight, meeting declivity in sharp diverging teeth, gently curved inwards when seen from above; declivity smooth, the meta pleural lobes not jointed over the foramen. Opening of the metapleural gland indistinct. Petiole with a short anterior peduncle, lacking an anteroventral process; petiolar node subquadrate, dorsally broadly convex in profile till it approaches the postpetiole where it ends abruptly in a right angle. Postpetiole low and small, gently convex in profile, in dorsal view very broadly attached to the gaster. Sting large and strongly sclerotized, disproportionately powerful.

Queen
Larger, but not very much, than conspecific worker. Compound eyes with several facets over the largest diameter. Otherwise description as worker.