Doleromyrma

Doleromyrma are frequently encountered, most commonly in dry forested areas including coastal scrub or heath. They nest in soil, under rocks or rotten logs, or occasionally in abandoned nests of other ants. Nests usually contain several hundred workers which disperse quickly into protected areas when disturbed. They are occasionally pests in houses (Nikitin 1979) and have been introduced into New Zealand (Keall and Somerfield 1980).

Doleromyrma contains a single described species and two "subspecies" and has received little attention in the literature. It was originally established as a subgenus of Tapinoma (Forel 1907), was then synonymised with Iridomyrmex (Emery 1912), but is now treated as a distinct genus (Shattuck 1992).

Identification
The front margin of the clypeus above the mandibles with downwardly curved hairs which are about one-half the length of the closed mandibles. The mandibles with 4 or 5 large teeth and 4 or 5 small denticles, and with a moderately distinct angle between the surface containing the teeth and the surface near the clypeus (basal angle present). The upper face of the propodeum is shorter than the rear face. The petiole is strongly inclined forward but is angular above and the forward and rear faces are present and distinct. The first segment of the gaster projects forward and partially conceals the petiole when viewed from above.

Species of Doleromyrma are most often confused with those of Iridomyrmex, Plagiolepis and Tapinoma. They differ from Iridomyrmex in having the front margin of the clypeus concave in the centre, rather than having a projection. They can be separated from Plagiolepis by the lack of an acidopore. Separating Doleromyrma and Tapinoma can be difficult. Both are about the same overall size and colour, and their mesosomas are essentially identical. They differ in that the hairs on the front margin of the clypeus (above the mandibles) are downwardly curved in Doleromyrma while they are straight in Tapinoma. Doleromyrma has fewer teeth on the mandibles and the mandibles have a moderately distinct angle between the surface with teeth and the surface near the clypeus (in Tapinoma this region of the mandible is rounded). The petioles also differ, with Doleromyrma always having distinct forward and rear faces which are separated by a sharp angle. In Tapinoma, the node of the petiole is generally absent as the forward face is greatly reduced and often completely absent.

Description
WORKER

HEAD. Vertex flat. 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. Anteromedial clypeal margin entire, without a central notch or concavity of any type (or sometimes with a very weak, narrow concavity). Anterior clypeal setae 6-8; short, less than twice the maximum scape diameter; moderately curved ventrally. 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. Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp segment at the apical extreme of segment 4. Mandible with 4-5 teeth and 4-5 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 distally, smooth proximally (sometimes entire surface nearly smooth). MESOSOMA. Posteroventral pronotum lateral, rounded. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Declivitous face of propodeum convex; dorsal face convex, shorter than the declivitous face. Propodeal angle moderately distinct. Mesosomal spines and tooth absent. Erect pronotal hairs absent. Dorsal pro-mesonotal junction with the pronotum and mesonotum even. Metanotal groove forming a distinct angle between the mesonotum and propodeum (sometimes reduced). Metanotal spiracle lateral and ventral of 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; ridged and with a distinct angle dorsally; moderately inclined anteriorly but with the anterior and posterior faces approximately the same length. Venter with a well developed lobe. GASTER. First tergite projecting anteriorly, but not concealing the petiole in dorsal view and with a groove or indentation for the reception of the entire height of the petiole. Anterior tergosternal suture of the first segment extending laterally from the helcium in a distinct arch which extends dorsal of the dorsal helcial surface. Fifth tergite ventral, gaster with 4 apparent tergites. Gastral compression absent (gaster circular in cross section). Fourth sternite flat across entire posterior border. GENERAL CHARACTERS. Worker caste monomorphic. Chromosome number 6 or 7 (n=7, 2n=14, D. "darwinianus-group" sp. ANIC-8, Imai et al. 1977; 2n=12, D. "darwinianus-group" sp. ANIC-9, Imai et al. 1977). Integument thin and flexible, weakly sculptured. PROVENTRICULUS. Not examined.

QUEEN

HEAD. Vertex 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. Anteromedial clypeal margin entire, without a central notch or concavity of any type. Anterior clypeal setae 10-14; 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. Anterolateral hypostoma reduced to a thin sclerite. Medial hypostoma entire. 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 8 teeth and 6 denticles. Apical tooth slightly longer than the subapical tooth. Basal angle weakly defined by a denticle. Basal margin smooth and without teeth or denticles. MESOSOMA. Posteroventral pronotum lateral, rounded or angled. Episternal suture complete. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Axilla parallel and entire. Anterior axillar suture straight. Declivitous face of propodeum flat; dorsal face convex, subequal in length to the declivitous face. Propodeal angle distinct. Propodeal suture absent. Mesosomal spines and tooth absent. Erect mesoscutal hairs 0-6. 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 2 cubital and 1 discoidal cell. Hind wing with 2 cells. PETIOLE. Scale present; ridged and with a distinct angle dorsally; moderately inclined anteriorly but with the anterior and posterior faces approximately the same length. Venter with a well developed, rounded lobe. GASTER. First segment projecting anteriorly, but 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 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 barrel-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 6; 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. Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp at the apical extreme of segment 4. Mandible with 5-7 teeth and no denticles. Apical tooth elongate and much longer than the subapical tooth. Basal angle moderately to very distinct, with a distinct tooth or well defined angle separating the masticatory and basal margins. 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, very broad, and entire. Anterior axillar suture straight. Declivitous and dorsal faces of propodeum convex; dorsal face longer than the declivitous face. Propodeal angle distinct. WINGS. Radial cell closed. Fore wing with 1 cubital and 1 discoidal cell. Pterostigmal appendage absent. Hind wing with 2 cells. PETIOLE. Scale present; ridged and with a distinct angle 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, 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 weakly down-turned tip. Cuspis absent. Ventral lobe of volsella present as concave lobe. Aedeagus with ventral teeth.

Nomenclature

 *  DOLEROMYRMA [Dolichoderinae: Leptomyrmecini]
 * Doleromyrma Forel, 1907a: 28 [as subgenus of Tapinoma]. Type-species: Tapinoma (Doleromyrma) darwinianum, by monotypy.
 * Doleromyrma subgenus of Iridomyrmex: Forel, 1912a: 81.
 * Doleromyrma junior synonym of Iridomyrmex: Emery, 1913a: 22; Wheeler, W.M. 1922a: 689.
 * Doleromyrma revived from synonymy and raised to genus: Shattuck, 1992a: 14; Shattuck, 1992c: 60.