Azteca

All known species are arboreal, nesting in living or dead wood, or external carton nests. Some species exhibit obligate associations with myrmecophytes, especially of the genus Cecropia. Feeding habits are generalized with foraging occurring both arboreally and on the ground. The species level taxonomy of this genus is in need of revision, with the exception of a few modern treatments that have carefully delineated numerous species within species groups or from specific areas. Workers tend to have few distinguishing characters. Queens are more distinctive, so much so that species are now described and identified from the queens rather than workers. Unfortunately collecting a queen can be an onerous task.....many species are very aggressive when their nests are disturbed.

Identification
Shattuck (1992) - Worker: Polymorphic, majors with ocelli; anterolateral clypeal margin with the corners expanded anterior of the mediolateral region; vertex concave; petiolar scale strongly inclined anteriorly, and with a distinct ventral node; dorsal face of propodeum longer than declivitous face; mandible with 7-9 teeth and no denticles, and with the apical tooth subequal in size to the subapical; metanotal groove forming a distinct angle between the mesonotum and propodeum. Central and South America. Queen: Propodeal angle indistinct; petiolar scale strongly inclined anteriorly and with the anterior face much shorter than the posterior face; venter of petiole with a well developed, rounded lobe; wing with one closed cubital cell. Male: Second funicular segment barrel-shaped; petiolar scale with a blunt angle or a single tooth or projection dorsally; pygostyles vestigial; mandible with 1 to 4 teeth and 0 to about 3 denticles; first gastral segment vertical (not concealing the petiole in dorsal view), and with a groove or indentation for the reception of the entire height of the petiole.

The worker caste can generally be recognized in the field by its cordate-shaped head, large foraging columns and habit of running with the gaster raised. Azteca workers are most similar to those of the Old World genus Anonychomyrma, but are separable based on the presence of ocelli in larger workers (ocelli are also present in one species of Anonychomyrma), a smaller subapical mandibular tooth, a strongly anteriorly inclined petiolar node, and a polymorphic worker caste. Additionally, the Azteca proventriculus is distinct in having the copula excised laterally, without phragma, and only slightly broader than the bulb; the bulb being exposed in lateral view; and the presence of an occlusory tract.

Species richness
Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data



Biology
During an Ant Course in Venezuela, Brian Fisher and Jack Longino opened a nest of these aggressive ants. Their YouTube video is well worth watching.

Nomenclature

 *  AZTECA [Dolichoderinae: Leptomyrmecini]
 * Azteca Forel, 1878: 384. Type-species: Liometopum xanthochroum, by monotypy.
 * [Type-species not Tapinoma instabilis, unjustified subsequent designation (based on inaccurate synonymy) by Wheeler, W.M. 1911f: 159. Type-species not Azteca muelleri, unjustified subsequent designation by Emery, 1913a: 31; repeated in Wheeler, W.M. 1913a: 78.]
 * [ Aztecum Bertkau, 1879: 13, incorrect subsequent spelling.]

Description
Shattuck (1992):

Worker
HEAD. Vertex weakly to strongly concave. Compound eyes present, approximately round; relatively anterior on head. Ocelli present (in majors). Antennae 12 segmented. Scape short, at most surpassing the vertex by less than one- third its length. Anterolateral clypeal margin even with the mediolateral region and commonly with the corners expanded slightly anterior of the mediolateral region. Anteromedial clypeal margin entire, without a central notch or concavity of any type. Anterior clypeal setae 6-14; short, less than twice the maximum scape diameter; straight. Posterior clypeal margin between the anterior and posterior surfaces of the antennal socket cavities. Anterior tentorial pit nearer the antennal socket than the mandibular insertion. Frontal carina present. Anterolateral hypostoma reduced to a thin sclerite. Medial hypostoma entire. Psammophore absent. MOUTHPARTS. Palp formula 6:4,5:3,4:3 or 4:2 (rarely 5:3 partly fused into 4:3). Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp segment at the apical extreme of segment 4. Mandible with 7-9 teeth and no denticles. Apical tooth subequal in length to the subapical tooth. Basal angle distinct, with a well developed tooth or angle separating the masticatory and basal margins. Basal margin varying from smooth (without teeth or denticles) to denticulate along entire surface. MESOSOMA. Posteroventral pronotum lateral, rounded or angled. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Declivitous face of propodeum convex; dorsal face flat or convex, longer than the declivitous face. Propodeal angle indistinct to moderately distinct. Mesosomal spines and tooth absent. Erect pronotal hairs 4-20 (rarely absent); when present elongate, much longer than the maximum scape width. Dorsal pro-mesonotal junction with the pronotum and mesonotum even, or with the mesonotum above the pronotum. Metanotal groove forming a distinct angle between the mesonotum and propodeum. Metanotal spiracle dorsal and lying on the dorsal surface when viewed in lateral profile. Propodeal spiracle lateral and ventral of the propodeal dorsum (sometimes appearing dorsal because of reduction of dorsal propodeum). Hind tibial spur with well developed barbules along entire inner surface (except extreme base). PETIOLE. Scale present; ridged and with a distinct angle dorsally; strongly inclined anteriorly and with the anterior face much shorter than the posterior face. Venter with a well developed lobe. GASTER.• First tergite vertical and not concealing the petiole in dorsal view and with a groove or indentation for the reception ofthe basal portion ofthe petiole. Anteriortergosternal suture ofthe first segment extending laterally from the helcium, without or with at most a very weak dorsal arch. Fifth tergite ventral, gaster with 4 apparent tergites. Gastral compression lateral, dorsoventral, or absent (gaster circular in cross section). Fourth sternite keel-shaped posteriorly. GENERAL CHARACTERS. Worker caste polymorphic. Chromosome number unknown. Integument thin and flexible, weakly sculptured. PROVENTRICULUS. Cupola slightly broader than bulb; excised; with short pile; smooth, without sculpture; and without phragma. Bulb exposed in lateral view. Longitudinal muscle No.1 present. Occlusory tract present.

Queen
HEAD. Vertex weakly convex to weakly concave. Compound eyes relatively anterior on head. Antennae 12 segmented. Scape short, surpassing the vertex by less than one-half scape length. Anterolateral clypeal margin even with the mediolateral region, or occasionally with the corners expanded slightly anterior of the mediolateral region. Anteromedial clypeal margin entire, without a central notch or concavity of any type. Anterior clypeal setae 8-10; short, less than twice the maximum scape diameter; straight. Posterior clypeal margin between the anterior and posterior surfaces of the antennal socket cavities. Anterior tentorial pit nearer the antennal socket than the mandibular insertion. Anterolateral hypostoma reduced to a thin sclerite. Medial hypostoma entire. Psammophore absent. MOUTHPARTS. Palp formula 6:4 or 4:3 (and possibly others, see worker description). Third maxillary palp segment (when present) subequal in length to segment 4. Fifth maxillary palp segment (when present) at the apical extreme of segment 4. Mandible with 7-8 teeth and 0-1 denticles. Apical tooth subequal in length to, to slightly longer than, the subapical tooth. Basal angle distinct, with a well developed tooth or angle separating the masticatory and basal margins. Basal margin varying from smooth (without teeth or denticles) to denticulate along entire surface. MESOSOMA. Posteroventral pronotum lateral, rounded or angled. Episternal suture complete. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Axilla subparallel (very weakly constricted), constricted medially, or absent dorsally; when present, entire. Anterior axillar suture (when present) straight or angular medially. Declivitous face of propodeum convex; dorsal face convex, subequal in length to the declivitous face. Propodeal angle indistinct. Propodeal suture absent. Mesosomal spines and tooth absent. Erect mesoscutal hairs about 16-100; short, less than twice the maximum scape diameter to elongate, more than twice the maximum scape diameter. Propodeal spiracle lateral and ventral ofthe propodeal dorsum. Hind tibial spur with well developed barbules along entire inner surface (except extreme base). WINGS. Radial cell closed. Fore wing with 1 cubital and 1- 2 discoidal cells. Hind wing with 2 cells. PETIOLE. Scale present; ridged and with a distinct angle dorsally; strongly inclined anteriorly and with the anterior face much shorter than the posterior face. Venter with a well developed, rounded lobe. GASTER. First segment vertical and not concealing the petiole in dorsal view and with a groove or indentation for the reception of the entire height of the petiole. Fifth tergite vertical and with the distal terminus of the gaster not well defined. Gastral compression absent (gaster circular in cross section). Fourth sternite flat across entire posterior border.

Male
HEAD. I nner margin of eye entire, flat. Scape length shorter than the length of funicular segments 2+3. First funicular segment barrel-shaped. Second funicular segment barrel-shaped, straight. Funicular segments 2 and 3 at most twice as long as broad. Third and fourth funicular segments straight. Anteromedial clypeal margin entire, without a central notch or concavity of any type. Anterior clypeal setae 4-10; short, about as long as the maximum diameter of the scape; straight. Posterior clypeal margin even with or anterior to the anterior surfaces of the antennal socket cavities. Anterior tentorial pit nearer the antennal socket than the mandibular insertion. Anterolateral hypostoma reduced to a thin sclerite. Medial hypostoma entire. MOUTHPARTS. Palp formula 6:4 or 5:3 (and possibly others, see worker description). Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp at the apical extreme of segment 4. Mandible with 1-4 teeth and 0 - about 3 denticles. Apical tooth distinct. Basal angle indistinct, with a relatively uninterrupted curve between the two margins and without a distinct tooth or angle. Basal margin smooth and without teeth or denticles. MESOSOMA. Posteroventral pronotum lateral, rounded or angled. Episternal suture present, complete. Anteromedial mesosternum even with the lateral regions. Axilla parallel or constricted medially, and entire. Anterior axillar suture straight. Declivitous face of propodeum convex; dorsal face convex, subequal in length to the declivitous face. Propodeal angle distinct. WINGS. Radial cell closed. Fore wing with 1 cubital and 1-2 discoidal cells. Pterostigmal appendage absent. Hind wing with 2 cells. PETIOLE. Scale present; a blunt angle dorsally, or spined with a single tooth or projection dorsally; vertical and not inclined anteriorly. Venter with a well developed lobe. Attachment to gaster broad. GASTER. First segment vertical and not concealing the petiole in dorsal view and with a groove or indentation for the reception of the entire height of the petiole. GENITALIA. Pygostyles vestigial. Posterior margin of subgenital plate convex or even across entire width. Paramere entire. Digitus linear, without a down-turned tip; tip sometimes slightly swollen. Cusp is absent. Ventral lobe of volsella present as a swelling. Aedeagus with ventral teeth.

Larva
Shape crematogastroid. Protuberances present as 2 bosses located ventrolaterally on prothorax. Body hairs sparse and moderately abundant; simple and hooked; short and elongate. 10 spiracular pairs. Antennae large.