Cephalotes dentidorsum

Identification
A member of the angustus clade differing from its sister species, Cephalotes adolphi, in the worker by the gaster very shining and smooth instead of opaque and sculptured.

Distribution based on Regional Taxon Lists
Neotropical Region: Peru.

Castes
Known only from a single worker.

Nomenclature

 *  dentidorsum. Cephalotes dentidorsum De Andrade, in De Andrade & Baroni Urbani, 1999: 734 (w.) PERU.

Worker
The description given by de Andrade (1999) is Kempf's (1960) description of what was thought to be Cephalotes adolphi:

Total length 3.9 mm; maximum length of head 1.20 mm; maximum width of head in front of the eyes 1.23 mm; maximum diameter of eyes 0.29 mm; Weber's length of thorax 1.12 mm; maximum width of gaster 1.12 mm. Light ferruginous; frontal carinae, occipital lobes, tips of thoracic and pedicellar spines, extensor face of tibiae testaceous.

Head subquadrate, supopaque, slightly broader than long. Mandibles finely and densely punctate, opaque. Clypeal suture vestigial. Frontal carinae semitranslucid, weakly sculptured throughout, nearly smooth and shining; their anterior border feebly crenulate. Sides of head excised in front of eyes, conspicuously upturned above eyes. Occipital lobes semitranslucid, foliaceous, with irregularly crenate border. Disc of cephalic dorsum notably convex in both directions. Upper surface of head finely, densely yet not heavily reticulate-punctate, somewhat shining, with rather large oval foveolae. Cheeks marginate below, more heavily shagreened, opaque, densely foveolate. Gular surface practically devoid of sculpture, quite shining.

Thorax conspicuously narrower than head, finely reticulate-punctate, the microsculpture superficial to obsolescent on dorsum which therefore is quite shining, heavier on sides which are opaque. Scapular corner free, angulate, and subdentate. Sides of pronotum anteriorly with a prominent spiniform tooth, followed by a broad, apically rounded, and conspicuously upturned lobe. Promesonotal suture obsolete. Mesonotum at each side anteriorly with a short tooth. Mesoepinotal suture more or less vestigial, not impressed. Basal face of epinotum grading into declivous face; their lateral border anteriorly with a small tooth, followed by a prominent spiniform tooth, and, farther down the declivous face, two more or less vestigial denticles. Dorsum of thorax with rather curved, elongate oval foveolae. Laterotergite of pronotum longitudinally costate. Rest of sides with elongate, horizontal foveolae. Legs subopaque, weakly shagreened. Femora spindle-shaped. Tibiae not prismatic.

Petiolar and postpetiolar nodes with a prominent spiniform appendage at each side. Dorsum of petiole with a pair of minute denticles. Dorsum of body of postpetiole, as seen in profile, moderately convex. Gaster short, oval, with obsolescent microsculpture, with broad, well-developed, hyaline lamellate anterolateral crests. Setigerous foveolae not developed.

Erect hairs scarce, a row of short, club-shaped setae along the rim of the frontal carinae and the sides of head back to the occipital angle. Longer, rather pointed setae on apex of gaster. Ground pilosity consisting of pale golden, appressed scale-like setae, sparsely covering the body and appendages of the insect. These scales are more conspicuous and distinctly canaliculate when lying in the foveolae of the dorsum and cheeks of head and on the thorax.

Scales of gaster simple, finer, and not lying in foveolae.

Measurements (in mm) and indices: TL 4.00; HL 1.00; HW 1.20; EL 0.30; PW 0.91; PeW 0.62; PpW 0.66; HBaL 0.40; HBaW 0.08; CI 120.0; PI 133.3; PPeI 148.6; PPpI 137.9; HBaI 20.0.

Type Material
Worker (unique), Peru, Valle Chanchamayo, 800 m, l.VIII.1939, Weyrauch.

Etymology
The species is named from the Latin dens (= tooth) and dorsum (back), referred to the characteristic pronotal spines.