Technomyrmex

Hita Garcia, Wiesel and Fischer (2013) - The majority of Technomyrmex species nest and forage arboreally or sub-arboreally and even the few species that nest in soil or leaf litter forage on trunks and in the canopy (Bolton, 2007). Some specialised myrmecophilous plants have been reported to house Technomyrmex species (Hölldobler & Wilson, 1990). The diet mainly consists of hemipteran honeydew, though most species also feed on dead or living arthropods or their brood (Bolton, 2007).

Identification
Bolton (2007) - The species can be divided into a number of distinctive species groups (Technomyrmex species groups).

Dolichoderine ants. Masticatory margin of mandible multidentate, with 12 - 14 teeth, without a basal angle; basal margin of mandible denticulate to crenulate. Palp formula 6,4 in the vast majority of species, reduced to PF 5,3 in two species (Technomyrmex pratensis and Technomyrmex lasiops) and to PF 4,3 In two species (Technomyrmex lujae and Technomyrmex reductus). Median portion of anterior clypeal margin transverse to very deeply incised. Eyes always present. Ocelli absent (but I or 3 present in many worker-queen intercastes of the albipes group). Antenna 12-segmented, filiform or gradually incrassate towards the apex but without a club. Metanotal groove present. Propodeum unarmed, its dorsum-declivity junction broadly rounded to distinctly angular. Mesotibia and metatibia each with one spur, that on the metatibia pectinate. Petiole extremely reduced, forming a low narrow segment without a node or scale (there is a slight raised surface, immediately behind the peduncle, which provides the insertion-site of the exterior levator muscle). Ventral surface of petiole without, or with a very shallow, lobe. Petiole concealed in dorsal view when gaster is in line with mesosoma, overhung by the anteriorly projecting first gastral tergite. Overhanging portion of first gastral tergite ventrally with a groove that accommodates the entire petiole. Gaster with five visible tergites and sternites, the pygidium small. This short diagnosis will serve to isolate extant Technomyrmex workers from other dolichoderines.

Among the Dolichoderinae only the genera Technomyrmex and Tapinoma have the petiole reduced to such an extent that it is entirely overlapped and concealed by the projecting anterior portion of the first gastral tergite when the gaster is in line with the mesosoma. The structure of the gastral apex in Tapinoma is unique and immediately diagnostic of the genus. Instead of the usual five tergites only four are visible in dorsal (and sometimes also in lateral) view. This is because the fifth tergite is reflexed, folded below the fourth and in effect forms the apical part of the ventral surface. This usually differentiates Tapinoma immediately from Technomyrmex but some species of the former have such thin cuticle that the gaster often deforms or collapses on drying, which may make interpretation of the apex difficult. It is worth noting that such deformation of the gastral apex is common in small Tapinoma species but is infrequent in Technomyrmex.

Shattuck (1992) - Worker: Fifth gastral tergite dorsal; petiolar scale reduced or absent; first gastral segment projecting anteriorly and concealing petiole in dorsal view; anteromedial clypeal margin with a broad, shallow concavity, or with a distinct, central notch separated from the general outline of the margin by indistinct, arched corners; dorsal face of propodeum shorter than declivitous face; generally 2 to 10 erect hairs on pronotum. Primarily Old World, with one species in Central America and a widespread tramp species. Queen: Petiolar scale reduced; fifth gastral tergite dorsal; dorsal face of propodeum shorter than declivitous face; first gastral segment projecting anteriorly and concealing petiole in dorsal view; basal angle of mandible indistinct, with a relatively uninterrupted curve between the masticatory and basal margins; hind wing without closed cells. Male: Anteromedial clypeal margin with a broad, shallow concavity; mandible with about 19 teeth, and with the basal margin denticulate along the entire surface; petiolar scale strongly inclined anteriorly; first gastral segment projecting anteriorly, concealing the petiole in dorsal view; hind wing without closed cells.

This genus can be most easily separated from other dolichoderines based on the configuration of the gaster. The terminal gastral tergite is dorsal, giving the gaster a five-segmented appearance in dorsal view. In a few African species, the fifth gastral tergite is positioned more vertically than in most other members of the genus, but the tergite is still just visible in dorsal view.

Fisher and Bolton (2007) - Within the Dolichoderinae two genera, Tapinoma and Technomyrmex, are isolated in their female castes by the synapomorphic extreme reduction of the petiole and its accommodation in a longitudinal groove or impression in the ventral surface of the first gastral tergite, which overhangs and conceals the petiole in dorsal view when the mesosoma and gaster are aligned. The petiole is so reduced in these two genera that in profile there is no trace of a node or scale; at most there is a very short raised surface immediately behind the peduncle. The function of this raised surface is to provide an insertion-site for the exterior levator muscle of the petiole.

Technomyrmex and Tapinoma are separated in the female castes by the contrasting morphologies of their gastral apices. In Technomyrmex the sclerites of the gastral apex are unspecialised, except that the pygidium is small. Gastral tergite 5 is therefore in line with tergites 1 – 4 and as a result all five tergites are visible in dorsal view. In contrast the pygidium in Tapinoma is reflexed, the fifth tergite being folded back and down, below the fourth tergite, and is clearly visible in ventral view. Also in that view the fourth tergite frequently forms a distinct projecting rim above the reflexed fifth. In consequence only gastral tergites 1 – 4 are visible in dorsal view.

Distribution
Bolton (2007) - Ants of the genus Technomyrmex are mainly distributed throughout the tropical and sub-tropical zones of the Afrotropical region (29 species) and the Oriental and Malesian regions (45 species). There are smaller faunae In the Malagasy and Austral regions (12 and 13 species respectively) and two species that are restricted to the southern Palaearctic. Strangely, there is also a single, endemic Neotropical species that is restricted to small areas of Costa Rica and Panama.

Shattuck (1992) - The majority of species occur from Africa, east through southern Asia, to Australia. A single species (with one subspecies) is known from Panama, and is the only native New World species. A tramp species (Technomyrmex albipes) has been widely distributed by human activity, and is known from California and Florida (Deyrup 1991), USA, London, England, and many Pacific Islands (Wilson and Taylor 1967).

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



Biology
Bolton (2007) - In certain restricted localities individuals of single Technomyrmex species may be very numerous but in general they form only a relatively minor fraction of the total local ant fauna, both in terms of number of species and number of individuals. Locations where individuals of single species occur in huge numbers, other than when invading houses, are generally in stands or plantations of tree crops. Room (1971) found Technomyrmex moerens (recorded as T. sp.) to be very common in plantations of Theobroma cacao in Ghana, and Technomyrmex albipes on the same crop in Papua New Guinea (Room, 1975). Technomyrmex lujae (recorded as T sp. 2) was the most numerous ant species in the canopies of Terminalia ivorensis trees in southern Cameroun (Watt, Stork & Bolton, 2002) where it made up 80% of the total number of canopy ants sampled. T albipes is also very common in coconut plantations in Sri Lanka, Malaysia ana Philippines (Way & Bolton, 1997), but never seems to be a dominant species on this crop. Apart from these rather special cases the relative numbers seem low. For instance, at Pasoh Forest Reserve, West Malaysia, Bolton (1998) recorded that Technomyrmex accounted for only 4.8% of species (8% of individuals) in canopy samples, and 2% of species (1.5% of individuals) in leaf litter samples. A survey of leaf litter ants carried out in Ghana (Belshaw & Bolton, 1994) found that Technomyrmex comprised 2.5% of total species and only 3.5% of total individual ants.

The majority of Technomyrmex species are arboreal or sub-arboreal, with a very limited number apparently restricted to life in the leaf litter layer, but even those species which nest in the ground mostly also ascend shrubs and trees to forage on the trunks and in the canopy. A very few species appear to be associated with myrmecophytes. Lists of the specialised myrmecophilous plants that have been recorded as housing Technomyrmex species are given in Holldobler & Wilson (1990) and Davidson & McKey (1993). For the most part no names of Technomyrmex species are given in these lists but this survey has recorded Technomyrmex laurenti, Technomyrmex indicus, and a single record of albipes, from myrmecophyte domatia. Honeydew from a wide range of homopterous insects appears to form the main diet although most species will also scavenge for protein, both alive and dead, usually in the form of other arthropods or their eggs. Colony reproductive strategy in most species seems the same as is general throughout the Forrnicidae, with alate males and queens engaging in a nuptial flight, but members of the T. albipes group have a unique strategy that involves reproductive ergatoid worker-queen intercastes and ergatoid males, as well as the usual alate sexual forms. This feature is discussed under the two species where it has been investigated, T. difficilis and T. brunneus.

Shattuck (1992) - Species of Technomyrmex are most common in moist, forested regions. They nest in the soil, in twigs or branches, or in carton nests under leaves or on tree trunks. They are general scavengers and often forage in columns. At least one species is known to have ergatoid males (Terron 1972), and ergatoid queens have been collected in Papua New Guinea (P. S. Ward, pers. comm.).

Fernández and Guerrero (2008) - Technomyrmex and Bothriomyrmex could represent those groups probably widespread in the past and now limited to some scattered forested spots in the Neotropical forests, probably as retreating lineages. Leptomyrmex, also present in Miocene times were extinct in the New World, as some others ants taxa (Wilson 1988).

Nomenclature

 *  TECHNOMYRMEX [Dolichoderinae: Tapinomini]
 * Technomyrmex Mayr, 1872: 147. Type-species: Technomyrmex strenuus, by monotypy.
 * Technomyrmex senior synonym of Aphantolepis: Brown, 1953h: 5.
 * Technomyrmex senior synonym of Engramma: Shattuck, 1992c: 153.
 * Technomyrmex senior synonym of Tapinoptera: Bolton, 2007a: 4.
 * APHANTOLEPIS [junior synonym of Technomyrmex]
 * Aphantolepis Wheeler, W.M. 1930d: 44. Type-species: Aphantolepis quadricolor, by monotypy.
 * Aphantolepis junior synonym of Technomyrmex: Brown, 1953h: 5.
 * ENGRAMMA [junior synonym of Technomyrmex]
 * Engramma Forel, 1905b: 180. Type-species: Engramma lujae, by monotypy.
 * Engramma junior synonym of Technomyrmex: Shattuck, 1992c: 153; Bolton, 2007a: 4.
 * TAPINOPTERA [junior synonym of Technomyrmex]
 * Tapinoptera Santschi, 1925g: 348 [as subgenus of Tapinoma]. Type-species: Tapinoma vexatum, by monotypy.
 * Tapinoptera junior synonym of Tapinoma: Shattuck, 1992c: 146.
 * Tapinoptera junior synonym of Technomyrmex: Bolton, 2007a: 4.

Bolton (2007) - A large proportion of the taxonomic confusion in the genus centres upon three accomplished and much-misidentified common tramp species of the T. albipes group, namely Technomyrmex albipes, Technomyrmex difficilis and Technomyrmex vitiensis. These three have been very widely spread by commerce and have almost universally all been referred to as albipes in the past. They have also been confused with a number of related and widely distributed common species that occur sympatrically with the tramps through parts of their range. Species such as Technomyrmex jocosus in the Austral region, Technomyrmex pallipes in the Malagasy and Afrotropical regions, Technomyrmex moerens in the Afrotropical region and Technomyrmex brunneus in the Oriental region all feature m the literature misidentified as albipes. The genuine tramp species tend to occur sporadically throughout all zoogeographical regions except the Neotropical, where only difficilis has been found (in Florida and Puerto Rico), and they are occasionally encountered in hothouses or dwellings in the Palaearctic and Nearctic regions.

Description
Shattuck (1992):

Worker
HEAD. Vertex convex to weakly concave. Compound eyes present, approximately round; relatively anterior on head. Ocelli absent. Antennae 12 segmented. Scape relatively short, at most surpassing the vertex by less than one-half (often less than one-third) its length. Anterolateral clypeal margin even with the mediolateral region. Anteromedial clypeal margin with either a broad, shallow concavity, or with a distinct, central notch separated from the general outline of the margin by indistinct, arched corners. Anterior clypeal setae 6-12; short, less than twice the maximum scape diameter to about the same length as the closed mandibles; 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. Frontal carina present.Anterolateral hypostoma reduced to a thin sclerite. Medial hypostoma entire. Psammophore absent. MOUTHPARTS. Palp formula 6:4, 5:3 or 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- 10 teeth and 2-15 denticles. Apical tooth subequal in length to, to slightly longer than, the subapical tooth. Basal angle weakly defined by a denticle to indistinct, with a relatively uninterrupted curve between the two margins. Basal margin varying from smooth (without teeth or denticles) to denticulate along entire surface. MESOSOMA. Mesopleural process absent. Anteromedial mesosternum even with the lateral regions. Declivitous face of propodeum convex; dorsal face convex to flat, shorter than the declivitous face (sometimes only slightly). Propodeal angle distinct. Mesosomal spines and tooth absent. Erect pronotal hairs 2-10 (sometimes 0, rarely up to 20); short, about as long as maximum scape width. Dorsal pro-mesonotal junction with the pronotum and mesonotum even. Metanotal groove forming a distinct angle between the mesonotum and propodeum. Metanotal spiracle either 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 reduced or absent; when present, angular and only slightly visible in profile; strongly inclined anteriorly and with the anterior face much shorter than the posterior face. Venter with a slight or weakly developed lobe. GASTER. First tergite projecting anteriorly and 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 absent immediately lateral ofthe helcium and with the lateral section ofthe suture extending anterodorsally and terminating near the dorsal surface of the gaster. Fifth tergite dorsal, gaster with 5 apparent tergites. Gastral compression dorsoventral or rarely lateral. Fourth sternite flat across entire posterior border (some species with fan of erect hairs around apex of gastral sternite 4, similar to many formicines). GENERAL CHARACTERS. Worker caste monomorphic or rarely polymorphic. Chromosome number 8, 9, 14 or 15 (2n=16, Technomyrmex albipes, Imai et a/. 1977, Imai et a/. 1984; n=9, 2n=18, T. albipes, Crozier 1968a; 2n=28, T. sp.1, Imai et a/. 1985b; 2n=30, T. sp.2, Imai et a/. 1985b; 2n=30, T. sp.1, Imai et a/. 1985a; 2n=28, T. bicolor group, Imai et a/. 1984). Integument thin and flexible, weakly sculptured. PROVENTRICULUS. Cupola much broader than bulb; lobed; with short pile; with hexagonal sculpturing; and without phragma. Bulb partially hidden by cupola in lateral view. Longitudinal muscle No.1 absent. Occlusory tract absent.

Queen
HEAD. Vertex flatto 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 variable, either entire (without a central notch or concavity of any type); with a broad, shallow concavity; with a distinct, central notch separated from the general outline of the margin by indistinct, arched corners; or with a distinct, central notch separated from the general outline of the margin by distinct, angular corners. Anterior clypeal setae 6-12; short, less than twice the maximum scape diameter to about the same length as the closed mandibles; 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. Psammophore absent. MOUTHPARTS. Palp formula 6:4 (and possibly others, see worker description). Third maxillary palp segment subequal in length to segment 4. Fifth maxillary palp segment at the apical extreme of segment 4. Mandible with about 4-16 teeth and about 0-16 denticles. Apical tooth subequal in length to, to slightly longer than, the subapical tooth. Basal angle indistinct, with a relatively uninterrupted curve between the two margins and without a distinct tooth or angle. Basal margin varying from denticulate distally, smooth proximally 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. Axi11a constricted medially or rarely parallel, and entire. Anterior axi11ar suture straight. Declivitous face of propodeum convex to flat; dorsal face convex, shorter than the declivitous face. Propodeal angle distinct or indistinct. Propodeal suture absent. Mesosomal spines and tooth absent. Erect mesoscutal hairs 0-30; when present, varying from short (less than twice the maximum scape diameter) to elongate (more 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 cubital and 0-1 discoidal cells. Hind wing ceJls absent. PETIOLE. Scale reduced; ridged and with a distinct angle dorsally; strongly inclined anteriorly and with the anterior face much shorter than the posterior face. Venter with or without a slight or weakly developed lobe. GASTER. First segment projecting anteriorly and concealing the petiole in dorsal view and with a groove or indentation for the reception of the basal portion of the petiole. Fifth tergite dorsal, gaster with 5 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 (rarely slightly shorter than the length of funicular segments 1 +2 +3 and surpassing the vertex). First funicular segment cylindricalor 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 with a broad, shallow concavity, or less commonly entire, without a central notch or concavity of any type. Anterior clypeal setae 4-8; short, about as long as the maximum diameter of the scape and about the same length as the closed mandibles (both lengths present); 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 5:4 (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 about 19 teeth and no denticles. Apical tooth slightly longer than the subapical tooth. Basal angle indistinct, with a relatively uninterrupted curve between the two margins and without a distinct tooth or angle. Basal margin denticulate along entire surface, or rarely denticulate distally, smooth proximally. 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 and dorsal faces of propodeum convex; dorsal face shorter than the declivitous face. Propodeal angle indistinct. WINGS. Radial cell closed. Fore wing with 1 cubital and no discoidal cells. Pterostigmal appendage absent. Hind wing cells absent. 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 slight or weakly developed lobe. Attachment to gaster narrow. GASTER. First segment projecting anteriorly and concealing the petiole in dorsal view and with a groove or indentation for the reception of the entire height of the petiole. GENITALIA. Pygostyles present. Posterior margin of subgenital plate concave or with a V-shaped notch. Paramere entire. Digitus with a down-turned tip. Cusp is ventral of digitus. Ventral lobe of volsella absent. Aedeagus with ventral teeth.

Larva
Shape pheidoloid or dolichoderoid. Protuberances present as a single boss on posterior of body. Body hairs sparse; simple; short. 9 spiracular pairs. Antennae short.

Fossils
Bolton (2007) - There are four fossil species currently included in the genus, mostly dubiously so. Two of these are from the Dominican amber, one from the Sicilian amber and one from an impression fossil from China. It should be noted that the identification of Technomyrmex in Poinar et al. (1999) was changed to Formicinae incertae sedis in Archibald et al. (2018) (Grimaldi et al., 2018).