Dorymyrmex biconis

In Columbia this species can be quite common in disturbed areas.

Identification
Cuezzo and Guerrero (2011) - Worker Concolorous reddish brown. CI: 84–107. Posterior margin of head straight to slightly convex. Mesosomal profile interrupted by the presence of two tubercles: one stout short metanotal tubercle, posteriorly directed, and another placed in apical corner of the propodeum, dorsally directed. Queen Color similar to worker but darker. Head subquadrate with a straight posterior margin. Compound eyes notably developed, longer than wide, placed in middle of lateral margin of head. Male Mandible thin, falcate, with only three teeth: one long apical tooth, one subapical, and one denticle. Masticatory and basal margin well differentiated, basal margins completely devoid of teeth or denticles.

Three species of Dorymyrmex (Dorymyrmex bituber, Dorymyrmex pulchellus, and Dorymyrmex tuberosus) share a few characters with D. biconis. This is a group of species easy to recognize by the presence of two well-developed mesosomal tubercles: one in the last part of the metanotum and the other one between the dorsal and declivitous faces of propodeum.

Distribution
North and central South America, from Venezuela to Peru.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Peru, Venezuela.

Biology
In Colombia, Dorymyrmex biconis is spread throughout, from sea level to more than 2300m. It is more common in lowlands (i.e., Colombian Caribbean region, North of Colombia) and quite common in anthropic environments, with higher abundance in urban places. Nevertheless, workers of D. biconis have been collected in primary dry forests and in mangroves. D. biconis builds nests in soil devoid of vegetation, in very warm areas. Exceptions are arid but extremely cold places such as Boyaca, Colombia. As in other species of Dorymyrmex, nests are superficial, with simple architecture, and no more than 10–15 cm in depth. Excavated nests by RJG in Santa Marta (Magdalena, Colombia) share a similar architecture: only one circular entrance (no more than 5 mm in diameter) surrounded by a mound of sand or other soil particles with a diameter of 9-10 cm. The nest consist of one chamber with queens and males, a second one with larvae and worker pupae, and a third chamber with food and insects remains, such as several Bruchidae (Coleoptera). In one nest, RJG collected some dead Thysanoptera in the food storage camera. One nest of D. biconis can keep between 10 to 15 alate queens, 8 to 10 males and several tens of workers. Sometimes there are no more than 100 to 200 workers in a single nest. No dealate queens have been found in explored nests. Colonies of D. biconis are probably polydomous, and queens may fly outside of its colony to build satellite nests. In some cases, RJG has found two or three nests in an area of 10m2; only one of these nests had queens. (Cuezzo and Guerrero 2011)

Nomenclature

 *  biconis. Dorymyrmex biconis Forel, 1912h: 37 (w.) COLOMBIA. Cuezzo & Guerrero, 2011: 8 (q.m.). Combination in Conomyrma (Biconomyrma): Kusnezov, 1952g: 430; in Dorymyrmex: Shattuck, 1992c: 85.

Worker
Cuezzo and Guerrero (2011) - (n = 62): HL: 0.56–1.16; HW: 0.62–1.20; EL: 0.18–0.34; EW: 0.16–0.32; SL: 0.78–1.10; WL: 1.00–1.12; CI: 84–107; SI: 93–127; REL: 24–33; OI: 55–88; TLI: 128–191.

Concolorous reddish brown, whitish pubescence covering all body tagma. Some specimens have some segments of gaster darker than rest of the body. Worker length 2.8–3.0 mm. Head: subquadrate, longer than wide, with lateral sides straight to slightly convex, posterior margin of the head straight to slightly convex. Scape surpassing the posterior margin of head by no more than 1/3 of its length. Compound eyes placed far from posterior clypeal margin but in the first half of the head. Psammophore with short hairs disposed in a triangle; the hairs in the top line are near to the foramen magnum and do not reach the oral cavity. Mesosoma: mesonotum with a stout cone, rounded apically, and shorter than propodeal tubercle. Mesonotal tubercle directed posteriorly. Metanotal suture well developed and located inside a very pronounced concavity posterior to mesonotal tubercle. Dorsal face of propodeum anterior to tubercle sinuate. Metasoma: petiolar scale directed dorsally.

Queen
Cuezzo and Guerrero (2011) - (n = 7): HL: 1.10–1.16; HW: 1.18–1.20; EL: 0.40–0.46; EW: 0.28–0.32; SL: 1.06–1.12; WL: 2.04–2.32; CI: 102–107; SI: 93–102; REL: 36–40; OI: 61–76; TLI: 179–200.

Body reddish brown, darker than worker. Pubescence dense, with long, decumbent hairs covering all body tagma. Head: subquadrate. Head capsule with lateral margins parallel to slightly convex, especially in their posterior half. Posterior margin of head straight, with occipital corners rounded. Mandible with a long and sharp apical tooth, three additional teeth and four denticles along the masticatory margin; basal margin completely denticulate without any angle between both margins. Compound eyes notably large, longer than wide, placed in the middle of lateral sides. Scape surpassing the posterior margin of head by twice its maximum diameter. Mesosoma: parapsidal furrow slightly developed, visible in dorsal view as a tenuous line reaching posterior half of pronotum, diverging forwards, axilla not divided. Anepisternum and katepisternum incompletely divided by a short pleural suture. Pleural suture with long and abundant hairs (better observed in specimens preserved in EtOH). Wings: forewing with one close radial cell, only one cubital cell, no discoidal cell; pterostigma well developed, longer than wide. Hindwing with three closed cells, hamuli with 12 hooks. Metasoma: petiolar scale tall, directed dorsally, and apically obtuse. Petiolar ventral face straight with posterior end slightly convex. Gastral tergites dark brown, especially in posterior 2/3; sternite 1 and 2 lighter than the rest of the body.

Male
Cuezzo and Guerrero (2011) - (n = 5): HL: 0.56–0.60; HW: 0.58–0.62; EL: 0.30–0.34; EW: 0.24–0.28; SL: 0.22–0.24; WL: 1.24–1.36; CI: 100–107; SI: 38–41; REL: 50–59; OI: 75–88; TLI: 217–234.

Body dark brown to black, mandibles yellowish brown except masticatory margin which is reddish brown; legs, except femora, lighter than rest of the body. Head and mesosoma strongly pointed. Pilosity with dense, decumbent, thin, and whitish hairs covering all tagma. Katepisternum and metapleural area with only a few hairs. Anterior face of petiolar scale with 2-3 long hairs. Head: square. Posterior margin of head weakly concave medially; occipital corners rounded; dorsal face of head with a weak, middle furrow. Mandible thin and falcate, with parallel sides; one long apical tooth, three times longer than subapical one, one denticle, and a diastema before the angle with the basal margin. Masticatory and basal margin well differentiated; basal margins completely devoid of teeth or denticles. Posterior part of clypeus wide and reaching the toruli; anterior clypeal margin convex, with a subclypeal border thin, anteromedial part of clypeus straight. Antenna with exposed condyle; long scape (< to EL) reaching posterior margin of compound eye; pedicel as long as each flagellomere. Compound eye large, maximum length more than 2/3 of cephalic length. Median ocellus hyaline, well developed; lateral ocelli close to posterior margin of head. Mesosoma: pronotum long, comprises more than a half of mesosoma, projecting forward as an elbow with a strong depression medially; parapsidal furrows running parallel, reaching the middle part of pronotum, placed inside the depression. Mesonotum twice longer than wide. Anepisternum and katepisternum completely divided by a mesopleural sulcus. Dorsal face of propodeum not well differentiated form posterior face, with a strong declivitous face; propodeal spiracles strongly protruded. Wings: forewing with close radial cell, no close cubital nor discoidal cell. Hindwing without closed cells, hamuli with 12 hooks. Metasoma: petiolar scale low and apically rounded, without ventral petiolar process. Pygostyle stout and short, well developed; paramere stout, covered with long dark setae; digitus curved ventrally, longer than volsella; aedeagus serrate ventrally.

Type Material
Cuezzo and Guerrero (2011) - Syntypes. 2w, Sierra Nevada de Santa Marta, San Antonio, Guajira Prov., COLOMBIA.

Etymology
Cuezzo and Guerrero (2011) - The name of this species refers to the main diagnostic character of D. biconis: the presence of a pair of tubercles interrupting the mesosomal profile.