Anonychomyrma

Anonychomyrma species are common in moist to semi-arid forested areas (and are less common in rain forests). They nest either in soil with or without coverings, or arboreally in living or dead wood. Workers forage in conspicuous trails on the ground and on tree trunks. Although not studied in detail, they seem to be general predators and also collect plant juices. Some species are associated with the caterpillars of selected butterflies. Nest sizes are moderate to large, ranging from 500 to tens of thousands of workers. When disturbed, most species elevate their gasters and release strong, acrid smelling chemicals as a defensive measure.

Anonychomyrma differs from Iridomyrmex in habitat preferences and general ecology. Anonychomyrma prefers moister sites and is more often arboreal, while Iridomyrmex occurs primarily in drier sites and is predominantly terrestrial.

Identification
The front margin of the clypeus (just above the mandibles) is flat or convex. The scapes are about as long as the head. The first (apical) tooth of the mandible is only slightly longer than the second (subapical) tooth. The eyes are larger in diameter than the maximum diameter of the scape and are located relatively downward on the head near the mandibles. The petiole is upright and at most only moderately inclined forward.

In addition to the characters listed above, Anonychomyrma workers can be recognised by their usually square or slightly heart-shaped heads and compact bodies with domed pronotum, mesonotum and propodeum. Many species also produce a distinct odour that is often noticeable for quite a distance.

Extended diagnosis

Worker: Mandible with apical tooth slightly longer than subapical, basal angle distinct and with a well developed tooth or angle separating the masticatory and basal margins, and basal margin denticulate along entire surface; gastral compression absent (gaster circular in cross section); fourth gastral sternite keel-shaped posteriorly; petiolar scale vertical and varying from not inclined anteriorly to moderately inclined anteriorly but with the anterior and posterior faces approximately the same length.

Queen: Anterolateral clypeal margin with the corners expanded slightly anterior of the mediolateral region, and the entire margin with 14 to 26 short erect setae; dorsal face of propodeum longer than declivitous face; 28 to 40 erect hairs on the mesoscutum.

Male: Mandible with 5 to 9 teeth, 0 to 4 denticles, a distinct basal angle (or if the angle is weakly defined, the masticatory and basal margins are readily separable), and with the basal margin denticulate along its entire surface.

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



Description
WORKER

HEAD. Vertex weakly convex to concave. Compound eyes present, approximately round; relatively anterior on head. Ocelli absent. 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 with the corners expanded slightly anterior of the mediolateral region (sometimes with the lateral region very slightly posterior of the mediolateral region). Anteromedial clypeal margin entire, without a central notch or concavity of any type, or less commonly with a broad, shallow concavity. Anterior clypeal setae 6-16; 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 (rarely with a small "V"-shaped notch). Psammophore absent. MOUTHPARTS. Palp formula 6:4. Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp segment at the apical extreme of segment 4. Mandible with 5-10 teeth and 0-5 denticles. Apical tooth slightly longer than the subapical tooth. Basal angle distinct, with a well developed tooth or angle separating the masticatory and basal margins. Basal margin denticulate along entire surface. MESOSOMA. Posteroventral pronotum lateral, rounded. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Declivitous face of propodeum weakly convex to flat; dorsal face convex, longer than to subequal in length to the declivitous face. Propodeal angle distinct to indistinct. Mesosomal spines and tooth absent. Erect pronotal hairs 4-70; elongate, much longer than the maximum scape width, or less commonly short, about as long as maximum scape width. Dorsal pro-mesonotal junction with the mesonotum above the pronotum, or with the pronotum and mesonotum even. Metanotal groove forming a distinct angle between the mesonotum and propodeum. Metanotal spiracle lateral and ventral of the dorsal surface, or dorsal and lying on the dorsal surface when viewed in lateral profile. Propodeal spiracle lateral and ventral of the propodeal dorsum. Hind tibial spur with well developed barbules along entire inner surface (except extreme base). PETIOLE. Scale present; rounded and forming an even arch dorsally, or ridged and with a distinct angle dorsally; vertical and not inclined anteriorly to moderately inclined anteriorly but with the anterior and posterior faces approximately the same length. Venter with a weakly to well developed lobe, or less commonly without a lobe. GASTER. First tergite vertical and not concealing the petiole in dorsal view and with a groove or indentation for the reception of the basal portion of the petiole (occasionally smooth and without a groove or indentation). Anterior tergosternal suture of the 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 absent (gaster circular in cross section). Fourth sternite keel-shaped posteriorly. GENERAL CHARACTERS. Worker caste monomorphic (rarely polymorphic). Chromosome number 8 (n=8, 2n=16, A. itinerans, Crozier 1968a; 2n=16, A. itinerans-group, sp. ANIC-10, Imai et al. 1977). Integument thin and flexible, weakly sculptured. PROVENTRICULUS. Cupola much broader than bulb; round; with short pile; smooth, without sculpture; and with short, lateral phragma. Bulb completely hidden by cupola in lateral view. Occlusory tract absent.

QUEEN

HEAD. Vertex weakly concave to 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 with the corners expanded slightly anterior of the mediolateral region. Anteromedial clypeal margin entire, without a central notch or concavity of any type, or less commonly with a broad, shallow concavity. Anterior clypeal setae 14-30; short, less than twice the maximum scape diameter; straight. Posterior clypeal margin posterior of 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 or occasionally very slightly notched. Psammophore absent. MOUTHPARTS. Palp formula 6:4. 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 0-4 denticles. Apical tooth slightly longer than the subapical tooth. Basal angle distinct, with a well developed tooth or angle separating the masticatory and basal margins. Basal margin denticulate distally, smooth proximally. MESOSOMA. Posteroventral pronotum lateral, rounded or angled. Episternal suture complete but weakly developed anteriorly. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Axilla parallel or very weakly constricted medially, and entire or with a suture medially. Anterior axillar suture straight. Declivitous face of propodeum convex or occasionally weakly concave; dorsal face convex, longer than the declivitous face. Propodeal angle distinct or indistinct. Propodeal suture weakly developed or absent. Mesosomal spines and tooth absent. Erect mesoscutal hairs 28-50; short, less than twice the maximum scape diameter. Propodeal spiracle lateral and ventral of the propodeal dorsum. Hind tibial spur with well developed barbules along entire inner surface (except extreme base). WINGS. Radial cell closed. Fore wing with 1-2 cubital and 1 discoidal cell. Hind wing with 2-3 cells. PETIOLE. Scale present; rounded and forming an even arch dorsally or ridged and with a distinct angle dorsally; vertical and not inclined to strongly inclined anteriorly (if inclined, the anterior face is much shorter than the posterior face). Venter with or without 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 either the basal portion or the entire height of the petiole. Fifth tergite ventral, gaster with 4 apparent tergites. Gastral compression absent (gaster circular in cross section). Fourth sternite flat across entire posterior border.

MALE

HEAD. Inner margin of eye entire, flat. Scape length shorter than the length of funicular segments 2+3. First funicular segment cylindrical or cone-shaped. Second funicular segment cylindrical, 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; short, about as long as the maximum diameter of the scape; 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. MOUTHPARTS. Palp formula 6:4. Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp at the apical extreme of segment 4. Mandible with 5-9 teeth and 0-4 denticles. Apical tooth slightly longer than the subapical tooth. Basal angle distinct, with a well developed tooth or angle separating the masticatory and basal margins, or weakly defined by a denticle (but with the masticatory and basal margins readily separable). Basal margin denticulate along entire surface. MESOSOMA. Posteroventral pronotum lateral, rounded or angled. Episternal suture present, complete. Anteromedial mesosternum even with the lateral regions. Axilla parallel, and entire or with a suture medially. Anterior axillar suture straight or angular medially. Declivitous and dorsal faces of propodeum convex. Propodeal angle indistinct. WINGS. Radial cell closed. Fore wing with 1 cubital and 1 discoidal cell. Pterostigmal appendage absent. Hind wing with 2 cells. PETIOLE. Scale present; rounded and forming an even arch dorsally; vertical and not inclined anteriorly. Venter with or without a well developed lobe. Attachment to gaster broad. GASTER. First segment vertical and not concealing the petiole in dorsal view, smooth and without a groove or indentation. GENITALIA. Pygostyles present. Posterior margin of subgenital plate concave. Paramere divided by a membranous region. Digitus with a down-turned tip. Cuspis parallel with digitus. Ventral lobe of volsella present as concave lobe. Aedeagus with ventral teeth.

LARVA

Shape dolichoderoid. Protuberances absent. Body hairs sparse; simple; short. 9 spiracular pairs. Antennae short.

Nomenclature

 *  ANONYCHOMYRMA [Dolichoderinae: Leptomyrmecini]
 * Anonychomyrma Donisthorpe, 1947c: 588. Type-species: Anonychomyrma myrmex, by monotypy.