Cephalotes unimaculatus

This species has been found nesting in small dead branches of living Acacia trees in Jaragua National Park (Dominican Republic) and is relatively common within the park. Foragers have been observed on vegetation in dry forest habitats at numerous locations across a range of elevations.



Identification
A member of the hamulus clade. The closest relative of unimaculatus is Cephalotes vinosus. Both share the regular body sculpture, the gaster differing in colour from the rest of the body and the pilosity partially hiding the sculpture. The yellow coloration on the gaster clearly separates C. unimaculatus from C. vinosus. (de Andrade and Baroni Urbani 1999)

Distribution based on Regional Taxon Lists
Neotropical Region: Dominican Republic, Greater Antilles, Haiti.

Biology
The Salticid spider Descanso formosus is a mimic of this ant.

Nomenclature

 *  unimaculatus. Cryptocerus unimaculatus Smith, F. 1853: 221, pl. 19, fig. 9 (w.) BRAZIL. De Andrade & Baroni Urbani, 1999: 101 (m.). Combination in Cryptocerus (Paracryptocerus): Emery, 1924d: 308; in Hypocryptocerus: Kempf, 1951: 151; in Zacryptocerus: Brandão, 1991: 384; in Cephalotes: De Andrade & Baroni Urbani, 1999: 100. Senior synonym of steinheili: Kempf, 1951: 151; of signatus: De Andrade & Baroni Urbani, 1999: 100. Subspecies of haemorrhoidalis: Kempf, 1951: 151. Revived status as species: De Andrade & Baroni Urbani, 1999: 100.
 * steinheili. Cryptocerus hamulus subsp. steinheili Forel, 1908c: 355 (w.) ANTILLES. Combination in Cryptocerus (Paracryptocerus): Emery, 1924d: 307. Subspecies of haemorrhoidalis: Emery, 1924d: 307. Junior synonym of unimaculatus: Kempf, 1951: 151.
 * signatus. Hypocryptocerus haemorrhoidalis subsp. signatus Wheeler, W.M. 1936b: 203 (w.) HAITI. Combination in Zacryptocerus: Brandão, 1991: 384. Junior synonym of unimaculatus: De Andrade & Baroni Urbani, 1999: 100. See also: Kempf, 1951: 150.

Worker
From de Andrade and Baroni Urbani (1999): Head shape as in the other species of the group. Eyes flat or convex.

Mesosoma robust, convex in side view. Scapular angles bearing a small denticle. Anterior pronotal border marked by a carina more impressed in larger individuals. Humeral angles with a pair of obtuse spines directed anteriorly. Pronotal sides straight, ending in a small tooth visible in dorsal view. Promesonotal suture variably impressed. Mesonotal teeth absent. Propodeal suture deeply impressed. Propodeum with differentiated basal and declivous faces. Basal face ca. 1/3 broader than long, with slightly convex sides anteriorly. Straightening posteriorly and with or without a small denticle; declivous face as long as the basal face, with slightly converging sides posteriorly, without central concavity. Propodeal spines as long as or longer than the basal face of the propodeum, thick in most specimens, diverging.

Petiole ca. 1 /3 broader than long, its anterior face truncate and marginate dorsally by a crenulate carina interrupted in the middle; its sides converging posteriorly and with a pointed tooth medially, sometimes reduced to a minute denticles in some specimens. Postpetiole as broad as or broader and longer than the petiole; postpetiolar spines broad and variably pointed, inserted anteriorly and curved backwards.

Gaster and legs as in hamulus.

Sculpture. Head minutely reticulate; vertexal area covered by broad impressions or foveae gradually shallower towards the cheeks. Anterior half of the head with small and faint foveae. Head dorsum between the frontal carinae covered by coarse reticulation superimposed by shallower foveae and faint, thin longitudinal rugosities. Frontal carinae coarsely reticulate. Ventral side of the head laterally covered by strong longitudinal striae. Cheeks punctated and superficially rugulose.

Mesosoma, petiole and postpetiole covered by strong, longitudinal, irregular striae, and superficial reticulation. Declivous face of the propodeum covered by thick, longitudinal, transversal or curve striae and reticulation superficial to deep. Anterior petiolar face covered by thick, longitudinal or transversal striae; some specimens have longitudinal higher striae substituted by transversal striation on the lower part.

First gastral tergite reticulate with or without superficial, longitudinal rugosities on part oron the whole of its surface. Corresponding sternite with superficial longitudinal rugosities on its sides, the rest with impressed reticulation and opaque or faintly reticulated and slightly shining.

Legs as in the other species of the group. Some specimens with transversal rugosities on theanterior and posterior faces of the femora.

Pilosity. As in hamulus.

Colour. Head, mesosoma, pedicel, sternites, ventral marginal area of first tergite and remaining tergites black, legs lighter. Frontal carinae, scapes, first funicular joints, tips of pronotal and propodeal spines dark orange to light brown; last funicular joints brown. Gastral dorsum and its ventro-external parts orange with a black, oval stripe from the posterior half up to the end of the first tergite. The black spot, anteriorly, can be rounded, broadly ornarrowly triangular, or gently concave in different specimens.

Measurements (in mm) and indices: TL 5.6-7.8; HL 1 .40-1 .80; HW 1 .68-2.1 6; EL 0.48-0.55; PW 1 .60-2.00; PeW 0.64-1 .00; PpW 0.88-1 .08; HBaL 0.62-0.76; HBaW 0.1 6-0.22; CI 1 09.1-120.0; PI 1 02.1-1 12.2; PPeI 1 88.0-256.2; PPpI 1 73.9-192.3; HBaI 25.8-28.9.

Male
From de Andrade and Baroni Urbani (1999): (previously undescribed). - Head (eyes included, mandibles excluded) about 1 /3 broader than long. Vertcxal margin incompletely carinate and straight. Vertexal angles obtuse, diverging towards the posterior border of the eyes. Vertex convex. Ocelli protuberant. Eyes convex. Frontal carinae converging anteriorly, diverging backwards and not reaching the posterior border of the eyes. Clypeus convex, its posterior half higher than the anterior one, almost truncate. Anterior border of the clypeus bidentate, concave medially and laterally. Mandibles without lateral carina. Scapes thick, twice as long as the first funicular joint; remaining funicular joints thickening from the base to the apex.

Mesosoma. Pronotum in dorsal view with convex anterior border. Scapular angles well visible in dorsal view. Humeral angles with a pair of pointed denticles. Pro notal sides marginate. Pronotal carina marked. Mesonotum convex; median Mayrian carina weakly impressed. Propodeum with differentiate basal and declivous faces; basal face with the sides gently converging posteriorly and with a pair of broad, pointed teeth; declivous face with converging sides and superficially carinate laterally.

Petiole narrower than the postpetiole and with the anterior border superficially concave; its dorsum flat, gently sloping anteriorly and marginate laterally; petiolar sides convex anteriorly and narrowing posteriorly. Postpetiole almost flat dorsally; posterior part of the dorsum with a pair of minute denticles. Anterior third of the sides of the postpetiole with a pair of short, pointed teeth.

Gaster almost as broad as the mesosoma.

Genitalia and subgenital plate as in Fig. 34.

Wings as in auricomus.

Sculpture. Head and mesosoma with minute reticulation; this sculpture is superimposed by irregular foveae and irregular rugosities, the rugosities transversal around the eyes, longitudinal on the frons and on the scutellum and absent on the mesonotum; the foveae more regular on the mesonotum. Declivous face of the propodeum and pleurae superficially reticulate, shining and with longitudinal, thick rugosities on the pro- and mesopleurae, irregular on the declivous face of the propodeum and on the metapleurae. Petiole and postpetiole reticulate and with irregular, longitudinal rugosities, more concentric on the dorsum of the postpetiole. First gastral tergite strongly reticulate. Remaining tergites and sternites superficially reticulate. Legs punctate, the punctures more impressed and denser on the tibiae.

Pilosity. As in hamulus.

Colour. Head, mesosoma and petiole black. Coxae and postpetiole brown. Gaster and legs orange.

Measurements (in mm) and indices: TL 6.64-7.20; HL 0.96-1.14; HW 1 .1 4-1.32; EL 0.51-0.55; PW 1 .08-1.28; PeW 0.44-0.51 ; PpW 0.52-0.54; HBaL 0.88-0.92; HBaW 0.12-0. 1 4; CI 1 15.8-1 1 8.7; PI 1 03 .1-105.5; PPe! 245.4-251 .0; PPpl 207.7-237.0; HBal 1 3.6-15.2.

Note: the male measurement are based on the sole two specimens available, an adult and a pupa. This fact should account for the differences between them. The lowest figures, however, refer always to the pupa.

Type Material
From de Andrade and Baroni Urbani (1999): Holotype worker labelled "Braz., Cryptocerus unimaculatus Smith." in the (KEMPF, 1951:151), examined. C. unimaculatus has been described from Brazil, a provenance confirmed by the label of the holotype which must nonetheless be considered as certainly wrong.

References based on Global Ant Biodiversity Informatics

 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Forel A. 1908. Ameisen aus Sao Paulo (Brasilien), Paraguay etc. gesammelt von Prof. Herm. v. Ihering, Dr. Lutz, Dr. Fiebrig, etc. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 58: 340-418.
 * Kempf W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Revista de Entomologia (Rio de Janeiro) 22:1-244
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Perez-Gelabert D. E. 2008. Arthropods of Hispaniola (Dominican Republic and Haiti): A checklist and bibliography. Zootaxa 1831:1-530.
 * Wheeler, William Morton. 1936. Ants From Hispaniola and Mona Island. Bulletin: Museum of Comparative Zoology at Harvard College. 80(2):192-211.
 * de Andrade, M.L. & C. Baroni Urbani. 1999. Diversity and Adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Serie B 271. 893 pages, Stuttgart