Cephalotes auriger

Identification
de Andrade and Baroni Urbani (1999) - A member of the texanus clade characterised, in the worker, by the thinner and less regular striation on the mesosoma, by the first gastral tergite bearing appressed, dense, broad, golden hairs, and by the presence of a bold area on the posterior border of the first gastral tergite.

Cephalotes auriger is the sister species of Cephalotes chacmul. Both species are very similar and - within the texanus clade - they share synapomorphically the anterior border of the pronotum separate from the first pair of pronotal teeth and the posterior face of the femora with superficial, longitudinal rugosities. The worker of C. auriger can be distinguished from that of Cephalotes chacmul, other than by the marked golden pilosity of the gaster, by the rugosities on the dorsum of the mesosoma less impressed, by the first gastral sternite with less longitudinal rugosities, and by the first gastral segment longer.

Key to Cephalotes Workers

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Nomenclature

 *  auriger. Cephalotes auriger De Andrade, in De Andrade & Baroni Urbani, 1999: 615, fig. 288 (w.) MEXICO.

Worker
Head subquadrate. Frons convex. Frontal carinae superficially crenulate, upturned above the eyes. Vertexal angles round and with crenulate margin. Vertexal margin gently concave medially. Mandibles with superficial lateral carina.

Mesosoma. Scapular angles visible i n dorsal view. Anterior pronotal border straight. Pronotal sides with a narrow lamella with three teeth, the first and the second pair pointed, the third obtuse. Promesonotal and propodeal sutures, in dorsal view, impressed on the sides. Mesonotum with a small pair of lateral teeth. Propodeum with differentiate basal and declivous faces; sides of the basal face with two pairs of teeth followed by a pair of denticles, the second pair of teeth larger than the first one; declivous face of the propodeum converging posteriorly.

Petiole. Anterior face truncate, bearing a small pair of denticles dorsally, posterior face sloping posteriorly. Petiolar sides diverging into a pair of long, pointed spines directed backwards, converging posteriorly after the spines. Postpetiolar node gently pointed in the middle dorsally; postpetiolar spines long, pointed, directed slightly forwards at the base and strongly curved backwards at the apex, the sides converging posteriorly after the spines.

Gaster. Oval with a pair of anterolateral, narrow, membranaceous expansions not reaching the stigma posteriorly.

Hind femora angulate. Hind basitarsi long and not broadening at the base.

Sculpture. Head minutely punctate and with foveae broader than their interspaces, diminishing in size anteriorly, denser on the vertexal angles. Frontal carinae with superficial, sparse foveae, sparser anteriorly. Ventral face of the head reticulate, longitudinally rugose, the rugae more irregular on the anterior half where they are superimposed to superficial, oval foveae. Mesosoma minutely reticulate, with superficial, slightly irregular, thin longitudinal, rugosities and foveae, the rugosities more impressed and regular on the propodeum. Pleurae reticulate, with longitudinal, thin, rugosities on the propleurae and dense, superficial, oval foveae on the meso- and metapleurae. Pedicel reticulate and with dense, oval foveae. First gastral tergite minutely reticulate; its anterior third with thin, longitudinal rugae. First gastral sternite minutely punctate and with thin, longitudinal rugosities on the anterior third and on the sides. Middle of the first gastral sternite shining. Legs with the same sculpture as the first gastral tergite but with the foveae more impressed on the distal part of the outer face of femora and tibiae. Posterior face of the femora with longitudinal, thin rugae.

Pilosity. Each fovea with an appressed hair; similar hairs but not originating from the foveae on the whole sides and on the center of the posterior half of the first gastral tergite; remaining parts of the first gastral tergite with thinner and shorter hairs. Sides of the frontal carinae, mesosoma, pedicel and first gastral tergite with slightly clubbed hairs. First gastral sternite and border of the remaining sternites with thin, subdecumbent, sparse, pointed hairs, longer on the border of the first sternite. First sternite also with appressed hairs thicker and shorter than the pointed hairs.

Colour. Black with lighter femora. Mesosomal and pedicellar spines, tibiae and tarsomeres yellowish to light brown, tarsi darker. Frontal carinae yellowish and semi-transparent. First gastral tergite with a pair of oval, anterolateral, orange spots partially hidden by the golden hairs and not surpassing the stigma posteriorly. Gaster, dorsally, and extensor face of the legs covered by thick, golden hairs.

Measurements (in mm) and indices: TL 3.59-4.02; HL 0.86-0.96; HW 0.92-1.04; EL 0.25; PW 0.78-0.89; PeW 0.49; PpW 0.56-0.59; HBaL 0.31-0.33; HBaW 0.07; CI 107.0-108.3; PI 116.8-118.0; PPeI 159.2-181.6; PPpI 139.3-150.8; HBaI 21.2-22.6.

Type Material
Holotype worker from Mexico, Quintana Roo, S. Miguel, Cozumel Island, VII.1959, N. L. H. KRAUSS; paratype worker same data as the holotype, both in.

Etymology
From the Latin auriger = bearing gold (Cicero), referred to the coloration of the gaster.