Types: 23 ouvrieres de diverses tailles, provenant des stations suivantes de Ziela (LaMOTTE): savane a 850 m.-, termitieres enfouies sous les herbes: F 108, T 125, 127, 128 130. Type femelle: une reine de T 125, presque surement de la meme espece. Cotypes: 3 ouvrieres du Nimba N.-E., mousses de la foret primaire (VILLIERS).
Par son clypeus fortement bidente, l'epinotum un peu anguleux et les n oe uds petiolaires dilates, M. occidentale s'ecarte fortement de tous les Monomorium africains connus, sauf peutetre du M. estherae WEBER trouve vers 1.700 metres dans les Monts Imatong (Soudan), et dont la description est imprecise. Par contre il est voisin d'un type americain: M. minimum (BUCK) (Californie, Texas). Je commencerai par la diagnose d' occidentale en soi, puis le comparerai aux deux autres.
Ouvrieres: Long.: 1,9 a 3,1 mm. La taille de la plupart des Monomorium varie du simple au double, et les ouvrieres major manquent souvent dans les collections. Aussi baserai-je surtout les caracteres sur des media de 2 a 2,4 mm., qui sont les individus les plus fre- quents dans les recoltes locales (18 sur 23 du Nimba).
Brun fonce, luisant, petioles presque noirs, clypeus et appendices jaune fonce. Les mayor sont plus noires, et les minor brun-jaunatres. Ponctuation rare, surtout visible sur la tete, en gros points tres espaces laissant une aire mediane lisse. Poils longs, jaunes, assez denses sur tout le corps. Tete assez courte, un peu elargie vers l'avant, occiput concave. Yeux moyens, de 35 facettes environ, leur bord posterieur au niveau du milieu des cotes. Clypeus tres aberrant(fig. 10, A), plus large et plus dente que chez les congeneres ethiopiens de cette espece. Les deux dents anterieures, aigues, ont entre elles une echancrure plus profonde qu'un demicercle, et cet intervalle est prolonge jusqu'entre les bases des antennes par une aire deprimee triangulaire, lisse. L'echancrure est maximum chez les minor et plus faible chez les grosses ouvrieres de 3 mm. Scape court, son bout distal est loin d'atteindre le vertex. Funicule moyen, son deuxieme article a peine plus large que long.
De profil, thorax peu convexe, allonge, epinotum a angle mousse; l'echancrure qui le separe du mesonotum est peu accusee; a cet endroit, l'epinotum surplombe legerement le mesonotum. Noeuds du petiole relativement tres gros et transversaux: la fig. 10 me dispense de les decrire longuement. L'epinotum presente vers son tiers anterieur une saillie anguleuse laterale, qui semble rare chez les autres Monomorium . Gastre grand, luisant.
Femelle: Long.: 5,5 mm. Noire, luisante, cuisses et scapes bruns, le reste des appendices jaune fonce. Plus ponctuee et poilue que l'ouvriere: de gros points espaces criblent tete et thorax, des points plus fins ornent petioles et abdomen. Tete finement striee en long, pilosite forte et dense. Le clypeus est tres semblable a celui de l'ouvriere, les noeuds du petiole sont plus courts mais assez analogues. Lateralement, un large sillon crenele separe l'epinotum du mesonotum (fig. 10, E).
F: tete vue de face; G: thorax et petioles de profil; H: les memes vus en dessus; I: base du funicule.
M. estherae WEBER 1943 possede aussi un clypeus bidente, mais l'espace entre les dents est bien moins concave, plus court qu'un demi-cercle. Le pro-mesonotum est bien plus convexe qu'ici, l'epinotum ne semble pas anguleux lateralement. WEBER n'indique pas sa couleur. Beaucoup plus proche d' occidentale est M. minimum , qui semble commun dans le sud des Etats-Unis. L'ouvriere est brun-rouge, les aretes frontales sont prolongees en arriere de la base des antennes (plus courtes ici). Le clypeus est moins ponctue, mais de forme semblable. Le second n oe ud petiolaire est plus epais, son bord anterieur bien plus oblique. La ponctuation est encore plus faible. A part cela, les ouvrieres sont conformes a occidentale. Mais la [[queen]] de minimum, de taille 4,3 mm., differe nettement d'occidentale [[queen]] par la tete non striee, plus longue que large (striee et carree ici), l'epinotum plus allonge, le second n oe ud plus surbaisse.
[[ worker ]]. Tete allongee. Lobes frontaux tres rapproches entre lesquels l'epistome est peu engage. Ce dernier a une forte carene mediane mousse en avant et se divisant en arriere en deux faibles carenes plus ou moins distinctes et peu divergentes. Bord anterieur de l'epistome triangulaire, a sommet mousse ou arrondi. Yeux rudimentaires. Antennes de 12 articles, a massue de 3 articles, le dernier beaucoup plus grand. Suture promesonotale obsolete. Suture mer tanotale imprimee et complete. Epistome anguleux, mais inerme. Pedicule faisant passage a celui des Solenopsis . Gastre ovoide.
I [introduced species]
The numerous species of this large and difficult genus are all small but form populous colonies, commonly with several fertile females.
The worker is usually monomorphic, in the subgenera Parholcomyrmex and Holcomyrmex tending more or less to dimorphism. Clypeus abrupt, not sharply marked off from the frontal area, with two longitudinal welts or ridges of ten bordering an impressed median area and terminating anteriorly in projections or teeth. (These welts are fused in the subgenus Syllophopsis ). Mandibles narrow, with few teeth. Maxillary palpi 1- to 2-jointed, labial palpi 2-jointed. Antennae 12-jointed, in a few subgenera 11-jointed, in one species ( M. decamerum ) 10-jointed, the club typically 3- jointed, but sometimes 4-jointed or indistinct. Promesonotal suture obsolete, the mesonotum more or less impressed at the mesoepinotal suture, the epinotum nearly always unarmed. Petiole pedunculate, with high node; postpetiole lower, rounded. Tibial spurs simple or lacking.
The female is always much larger than the worker, in some species wingless; in one Australian form (subapterum) with vestigial wings. Venation like that of Formica , with a discoidal cell, rarely without.
The male is smaller than the female, always winged, with 13-jointed antennae. Mesonotum usually without Mayrian furrows, genital appendages completely retractile.
The division of the genus was begun by Forel when he established the subgenus Martia . Emery1 has recently revised the grouping of species and has established several additional subgenera. Viehmeyer has also proposed a subgenus Corynomyrmex , and Santschi has since added the subgenera Syllophopsis and Isolcomyrmex . In a more recent paper,2 Santschi proposes to give Syllophopsis generic rank.
These subgenera (see the key, Part VII) may be arranged more or less according to their natural affinities in the following sequence:
The genus Monomorium , though cosmopolitan and of even wider distribution than Crematogaster since it occurs even in New Zealand and Patagonia, is represented by the great majority of species in the Old World. The Neotropical Region possesses only a few species of the typical subgenus Monomorium and the species of Martia , which are not known to occur elsewhere. The subgenera Notomyrmex , Adlerzia , and Chelaner are exclusively Australian. Anillomyrma is monotypic and known only from Ceylon. Isolcomyrmex and Syllophopsis are exclusively Ethiopian. Xeromyrmex is properly African but spreads into the Palearctic and Indian Regions. Holcomyrmex , Parholcomyrmex , and especially Monomorium , sensu stricto, are more widely distributed. Several of the species of Monomorium , sensu stricto, ( minutum , floricola , pharaonis ), Xeromyrmex ( salomonis ), and Parholcomyrmex ( gracillimum , destructor ) have been widely disseminated by commerce. The species of Holcomyrmex are harvesting ants of dry regions and this is true of certain Australian species which are allied to Parholcomyrmex , though I assign them to a new subgenus Protholcomyrmex (with the type Monomorium rothsteini Forel) to be described in a later paper.
California appears to have a single indigenous species of this genus, M. ergatogyna , a ground-nesting species which is widely but patchily distributed throughout the state except at high elevations. The reasons for treating M. wheelerorum as a junior synonym have been discussed above (under “Taxonomic Changes”). The introduced Pharaoh’s ant, M. pharaonis (Linnaeus) , is a frequent pest in buildings in urban California. A second introduced species, similar to M. pharaonis but with a more elongate head and more shagreened sculpture, has been collected once in the state (images and locality information on AntWeb).
Species identification: keys in Wheeler and Wheeler (1986g). Additional references: Adams and Traniello (1981), Andersen et al. (1991), Berndt and Eichler (1987), Bolton (1987), DuBois (1986, 2000), Fernández (2005), Heterick (2001), Jones et al. (1982a, 1982b), Knight and Rust (1990).
Monomorium Mayr 1855:452. Type-species: Monomorium monomorium Bolton (replacement name for Monomorium minutum Mayr , 1855:453, a junior secondary homonym of Atta minuta Jerdon 1851:105 [= m. pharaonis (l.) 1758: 580]); by monotypy (Bolton 1987:287).
Phacota Roger 1862a: 260. Type-species: Phacota sichelii , by monotypy. Phacota junior synonym of Monomorium : Ettershank 1966:82, syn. rev. Bolton 1987:281. [Synonymy by Fernandez (in press) 2.] Nothidris Ettershank 1966:105. Type species: Monomorium latastei by original designation. [Synonymy by Fernandez (in press) 2.]
Antichthonidris Snelling 1975:5. Type-species: Monomorium denticulatum , by original designation.
[Synonymy of genus by Heterick 2001:361 without species-level nomenclatural changes, synonymy of a. denticulata Fernandez (in press) 2.]
Epelysidris Bolton 1987:279. Type-species: Epelysidris brocha , by original designation. [Synonymy by Fernandez (in press) 2.]
(For synonymy in the genus Monomorium prior to 1988, see Bolton, 1987:287-288.)
Diagnosis of worker of Malagasy species.- Minute to moderate (total length approximately1.5-4.5 mm) monomorphic to polymorphic myrmicine ants. Palp formula 5,3, 3,3 3,2, 2,2 or 1,2. Mandible smooth or longitudinally striolate, with three to six teeth and denticles, apical tooth always much larger than the preceding tooth; basal tooth often reduced to a small or minute denticle or angle but enlarged in one species, basal tooth often separated by a diastema from remainder of the dentition in members of the M. hildebrandti group; mandibular shape triangular, linear-triangular, or strap-like with inner and outer edges parallel or nearly so. Median clypeal seta conspicuous in most Malagasy species and positioned at or slightly above a distinct anteromedian clypeal margin except in M. hildebrandti group, where it is positioned on underside of a protruding shelf, near to the true anteromedian clypeal margin; paired setae (one often shorter than the other) straddling midpoint of anteromedian clypeal margin present in some large workers of M. aureorugosum , M. fisheri and M. infuscum and some queens of M. fisheri . Clypeus raised medially, usually bicarinate, though carinae may be obscure or in form of multiple weak ridges; in full-face view, the anteromedian clypeal margin often narrow and projecting, but this sector broad and abruptly declivous (i.e., when viewed in profile) in several members of M. monomorium and M. hildebrandti groups. Frontal carinae straight or diverging slightly posteriad, absent behind frontal lobes. Frontal lobes weakly sinuate or more-or-less parallel in full-face view. Antennal scrobes absent. Antennae 11- to 12-segmented; club usually with three distinct segments, sometimes four, or without a distinct club, but club never two-segmented. Eyes often reduced (sometimes to one or two ommatidia) in M. hildebrandti group, small to fairly large in other groups; in full-face view, eyes generally set at about midline of head capsule, or slightly above or below, but occasionally set well into anterior sector of head capsule; in profile, eyes usually set at about midline or behind midline of head capsule, rarely in front of midline; eye shape usually elliptical, with more pronounced curvature of the inner margin, but can be elongate or ovoid and narrowed to a point anteriad.
Mesosoma with standing setae in most groups, these setae lacking in some members of M. salomonis group; standing setae short and bristle-like in members of M. shuckardi group. Metanotal groove most commonly deeply impressed, but weakly impressed, vestigial or absent in some taxa. Propodeal dorsum rounded onto declivitous surface, weakly or strongly angulate or armed with short denticles, spines lacking in Malagasy species; standing propodeal setae absent in some cases. Propodeal spiracle distinctly circular or nearly so, usually situated at about midlength, but placed anteriad or posteriad of midlength in some taxa, and close to propodeal dorsum in members of M. shuckardi group. Metapleural glands of moderate to small size, never hypertrophied. Propodeal lobes often small to vestigial, rarely acute-angled and prominent. Fore coxae larger than middle or hind coxae. Petiolar peduncle often with small anteroventral flange or protuberance, but this feature vestigial in many species. Petiolar spiracle well in front of node in several endemic species, slightly in front of or in anterior sector of node in remaining taxa, often rather dorsally situated. Petiolar node shape ranging from low and broadly conical or tumular to cuneate and strongly tapered, thick and asymmetrical in profile in some members of M. hildebrandti group, but never regularly cuboidal in Malagasy species; underside of node and peduncle commonly with fine, transverse rugulae in larger species of M. hildebrandti group. Anteroventral margin of postpetiolar sternite often conspicuous, this feature reduced or absent in members of M. destructor , M. pharaonis and M. monomorium groups. Gaster dorsoventrally compressed, with blunt lateral carinae on gastral tergites. Sting not prominent in Malagasy species.
Diagnosis of queen of Malagasy species.- Larger than conspecific worker, but not greatly so in some taxa. Palp formula, number of mandibular teeth and denticles and number of antennal segments as for conspecific worker. Ocellar triangle of three ocelli typical, but posterior ocelli may occasionally be reduced in size. Eyes large, generally elliptical, sometimes with a concavity in upper outer margin, but circular, semi-circular and ovoid eye shapes also occur.
Seen in profile, mesoscutum ranges from broadly convex to convex anteriad and flattened or even faintly sinuate posteriad. Mesoscutal pilosity always present. Pronotum, mesoscutum and mesopleuron often smooth and shining, but may be striolate or punctate to a greater or smaller degree; mesopleuron always divided by transverse furrow into upper anepisternum and lower katepisternum. Length-width ratio of mesoscutum and scutellum from near 7:3 to about 3:2. Axillae mostly well separated but may be contiguous or even reduced to a strip of thin cuticle, each individual axilla being indistinct. Metapleural sculpture most commonly in form of longitudinal striolae or striae, propodeum often unsculptured except for costulae on declivitous face, but where present frequently more marked than in conspecific worker. Dorsal propodeal face characteristically sloped, often almost vertical. Propodeal processes, where present, in form of small denticles or flanges, at most. Wing veins tubular and sclerotised in M. notorthotenes , M. hanneli , and in M. hildebrandti group, predominantly weak and depigmented in most M. monomorium group species, though wing veins are darkly pigmented without accompanying sclerotization in some species. Cross-vein m-cu present in all queens of M. hildebrandti group, in all M. notorthotenes queens and some M. hanneli queens, absent in other M. hanneli queens, rarely present in reproductives of M. destructor group (per Bolton 1987), and always absent in reproductives of M. monomorium and M. salomonis groups (information on the latter coming from Bolton 1987). Cross-vein cu -a always present in M. notorthotenes , M. hanneli and all members of M. hildebrandti group, always absent as a distinct vein in members of M. monomorium group (very rarely present as a vague shadow). (Alate queens seen only for M. hanneli , and M. hildebrandti , M. monomorium and M. shuckardi groups.) Petiole as for that of conspecific worker. No brachypterous queens seen among Malagasy Monomorium . Ergatoid females seen for both M. hildebrandti and M. monomorium groups.
Diagnosis of male of Malagasy species.- I have seen males only for M. notorthotenes , M. hanneli and the M. hildebrandti and M. monomorium groups, and can associate males with just 12 of the 36 Malagasy Monomorium species identified in this work. This is too incomplete a record for a proper diagnosis to be made, but of those males seen, all, except members of the M. salomonis group, possess conspicuous, often turreted ocelli. The compound eyes are almost invariably protuberant, tending to elongate in some species. The wing of the male, on the other hand, generally has the same venation as the conspecific female, but vein cu -a is lacking in all males of M. notorthotenes and M. hanneli . The males of the endemic M. notorthotenes are very small in relation to the conspecific queen, even smaller than many workers of this species, and have a distinctly fly-like habitus. Identified males of the M. hildebrandti group are also relatively small in relation to the queen and approximately the same size or smaller than the worker. However, the size disparity between queen and male is much less among M. monomorium group reproductives, in contrast to the often minute workers, e.g. the HML of the Monomorium madecassum queen is 3.01-3.12 mm, compared with 2.80-2.84 mm for the male. (By way of contrast, the HML for the M. madecassum worker is only 1.14-1.27 mm).
Malagasy species groups recognized as a result of this project
Despite the fact that Madagascar was separated from Africa in the late Jurassic about 165 MYBP, and from India only 88 MYBP (Krause 2003), the Malagasy Monomorium fauna has strong African affinities, and shares a number of species with eastern and southern Africa. However, several shared taxa have their distribution primarily in the middle and western parts of Africa. By way of contrast, the Malagasy representatives of another myrmicine genus, Pyramica, have much more decidedly Asian affinities (Fisher 2003).
Of most interest are four species of a group restricted to Madagascar that has not been previously categorized. I have called this the Monomorium shuckardi species group after the only member described prior to this work. Members of this group possess some of the most plesiomorphic characters known for the genus Monomorium , most notably a PF of 5,3. The placement of the petiolar spiracle well anteriad of the node and near to the midlength of the petiole is also a primitive feature shared only with a few Australian species in the M. bicorne , M. insolescens and M. kilianii species groups (Heterick 2001), and with members of the M. scabriceps group (Bolton 1987). However, other morphological features suggest a relationship at a basal level with the Monomorium destructor and Monomorium salomonis groups. These include the specialized small males (albeit, only known for Monomorium notorthotenes Heterick , sp. nov. ) also found in the M. destructor group (Bolton 1987), and the finely microreticulate or striolate body sculpture and lack of standing setae on the propodeum, both characteristic of various members of the M. salomonis group. All members of the M. shuckardi species group also share a sculptured mandible with the other two groups, the sculpture in this case being predominantly longitudinal striolae or striae. Virtually all collections have been in the south of the island, in Toliara Province.
Two other groups found naturally on Madagascar are the M. hanneli and M. hildebrandti groups. The M. hanneli group (one Malagasy species) is otherwise restricted to West Africa and Kenya, but members of the M. hildebrandti group (ten Malagasy species) in which the eye is reduced to one or two ommatidia are also widespread in Africa, Indo-Australia, Australasia, and the Pacific (Wilson and Taylor 1967; Heterick 2001). Monomorium subcoecum (not found in Madagascar) was described by Emery from the Antilles, in the Caribbean (Emery 1894b). However, whereas these two entities appear to constitute only a minor fraction of the African Monomorium fauna (with the exception of the widespread Monomorium cryptobium ), several of the species recognized in this work are abundant and widespread throughout Madagascar. As understood in this work, the M. hildebrandti species group includes those species placed by Bolton in the M. fossulatum species group. The name hildebrandti is here preferred as the designation of this group because this was the earliest named species, and the name " fossulatum " has been synonymized under sechellense (Bolton 1995).
Monomorium hanneli bears a strong superficial resemblance to members of the M. hildebrandti group in which the clypeal carinae are well-developed and the clypeus is projected forward. The appearance of the mesosoma is also similar, if not identical, and the compound eye in workers of M. hanneli and workers of most M. hildebrandti group species is reduced. However, as Bolton (1987) correctly adjudges, the appearance of both groups is due to convergence. The most highly visible way workers of the two groups are separable is the appearance of the smooth, vertically attenuate node and the smooth, elevated postpetiole found in the M. hanneli group. A slightly more subtle but equally important difference is in the placement of the median seta, which, with the ant in full-face view, is set at or slightly above the midpoint of the true anteromedian clypeal margin in M. hanneli and its African relatives (i.e., M. guineense , M. invidium and M. jacksoni ), and well underneath a protrusive ledge in those members of the M. hildebrandti group with a projecting clypeus. The wing is more strongly sclerotized in those members of the M. hildebrandti group that I have seen than it is in M. hanneli , and all of the former possess vein m -cu, whereas that vein is missing in M. hanneli males and at least some queens.
While the workers of most members of the M. hildebrandti group have eyes that are comparatively very small, usually being less than the greatest width of the antennal scape, this is not a universal trait. The general reduction in the size of the worker eye is perhaps a function of a cryptic or mainly subterranean lifestyle, since the colonies of most species in this group appear to favour rotting wood and leaf mould. Transverse ventral rugulae found under the petiole of the medium-size and larger species are absent from the small workers of M. cryptobium , M. ferodens , M. modestum and M. sechellense . Very smooth workers of some populations of M. hildebrandti also lack these rugulae. Apart from the almost total loss of vision, the species formerly recognized as belonging to the fossulatum group (including all those formerly placed in the genus Syllophopsis) share a gestalt common to M. hildebrandti and its allies. The very large Monomorium aureorugosum and Monomorium infuscum workers have distinctively triangular mandibles, well-separated antennal lobes and are heavily sculptured, but share the same petiolar structure (including the fine, transverse, ventral petiolar rugulae and asymmetrical nodal dorsum) of other large members of the species group. Monomorium ferodens has an aberrant PF of 3,2, but otherwise clearly belongs here. In summary, this group has the following shared worker apomorphies: (1) smooth, linear-triangular mandibles with a strongly oblique masticatory margin (except for M. aureorugosum and M. infuscum ), (2) an anteromedian clypeal seta (more rarely, paired setae) positioned well under a protrusive ledge, and (3) a primitively asymmetrical dorsum to the petiolar node. Reduced eyes and transverse, ventral petiolar rugulae are also found in many M. hildebrandti group species. Workers of most species in this group share with the M. hanneli group and several members of the M. monomorium group narrowly separated frontal lobes.
The M. destructor and M. salomonis species groups are represented by few species, and these are mainly tramp ants. Within the M. destructor group, Monomorium destructor is adventive to the island, having been brought across by human commerce at some time in the past, but the widespread distribution of Monomorium robustior suggests endemicity (thus also Bolton 1987). Within the M. salomonis group, Monomorium pharaonis and Monomorium subopacum , members of different complexes but with similar tramp tendencies, have clearly been introduced. The presence of Monomorium willowmorense , known from one worker collected from the north-east coast, is more puzzling. The monotypic Monomorium latinode species group is represented by M. latinode , which also has tramp tendencies, and is well-dispersed across the Indo-Australian region (Bolton 1987).
Monomorium monomorium species group members found in Madagascar are often abundant, but are not particularly diverse compared with the Afrotropical fauna, only 15 species being recognized here. It should be said, however, that the variability of several nominal species like M. termitobium is so great that molecular-based systematics is probably needed to give the taxonomy strong definition. Some of the taxa appear to belong to complexes identified by Bolton (1987), while others seem not to be closely related to members of the group found on the African mainland. Of the described species, M. madecassum is clearly referable to Bolton"s leopoldinum complex, albeit M. leopoldinum itself becomes a junior synonym of M. madecassum in this work. Monomorium exiguum and M. floricola were placed in the boerorum complex by Bolton, but this was confessedly for convenience, and even aside from the difference in antennal count (i.e., 11 antennomeres in M. exiguum and 12 in M. floricola ), the queens of the two species do not appear very similar. Monomorium exiguum is actually closely related to the Afrotropical Monomorium rosae (see my comments under the former). The other Monomorium with an 11-segmented antenna, M. nigricans , is of uncertain affinities, but may also belong to the M. exiguum complex.
Monomorium termitobium is here regarded as the senior synonym of M. binatu , M. exchao and M. imerinense . Through M. binatu and M. exchao , M. termitobium (along with the apparently closely related M. xuthosoma and M. sakalavum ) is associated with Bolton"s rhopalocerum complex, but as here conceived, the morphological parameters of that complex far exceed those designated by Bolton. Workers of Monomorium micrommaton and M. chnodes bear a close resemblance to hirsute, yellow workers of M. termitobium . The queen of M. micrommaton is relatively large, with a proportionately massive mesosoma and a broad, cordate head, quite different characters from those of the queen of M. termitobium . Monomorium chnodes possesses a square propodeum (unlike that seen in any workers of M. termitobium ) with a large propodeal spiracle, and some queens and workers have a five-toothed mandible - a feature otherwise unknown in the M. monomorium species group. However, preliminary molecular data place Monomorium chnodes close to M. platynodis , and both species possess a very short clypeus that, when seen in profile, descends towards the arc of the mandibles at almost 90 degrees. Monomorium platynodis , in fact, may represent a radiation derived from M. chnodes , with a reduction in the size and dentition of the mandible.
In Monomorium chnodes , M. flavimembra , M. lepidum , M. platynodis , and M. versicolor , the clypeal carinae are obsolete or only weakly defined and the anteromedian clypeal margin is depressed and moderately to strongly declivous when seen in profile - in the case of M. chnodes and M. platynodis being almost vertical, as mentioned above. In four of these species, the fourth (i.e., basal) tooth is greatly reduced or absent. Only M. chnodes has a strongly defined basal tooth. In M. chnodes , M. flavimembra , and M. lepidum , the petiolar node is more-or-less conical and the postpetiole is rounded, but in M. platynodis and M. versicolor the nodes are high and the petiolar node is strongly cuneate. The group is here called the flavimembra complex. Monomorium bifidoclypeatum is very similar to these species and almost certainly also belongs to this complex. Monomorium denticulus is a small member of the M. schultzei complex but does not appear to be conspecific with any of the described African forms.
Monomorium Mayr, 1855: 452. Type-species: Monomorium monomorium Bolton , 1987: 287.
Phacota Roger, 1862: 260. Type species: Phacota sichelli Roger , 1862: 262. Synonym of Monomorium : Ettershank, 1966: 82. Genus revalidated: Bolton, 1987: 281. Syn. rev.
Nothidris Ettershank, 1966: 105. Type-species: Monomorium latastei Emery , 1895: 10. Syn. n.
Antichthonidris Snelling, 1975: 5. Type-species: Monomorium denticulatum Mayr , 1887: 614. Junior synonym of Monomorium : Heterick, 2001: 361.
Epelysidris Bolton, 1987: 279. Type-species: Epelysidris brocha Bolton , 1987: 280. Syn. n.
For a full list of synonymies before Heterick (2001) see Bolton (1987: 287 - 288).
WORKER DIAGNOSIS (after Bolton, 1987: 289; Heterick, 2001: 363 - 364).
Monomorphic to polymorphic. Minute to moderately large in total length. Mandibles with 4 to 5 teeth. Maxillary palps with 2 to 4 segments. Median clypeal seta present, sometimes displaced or absent. Median portion of clypeus raised, longitudinally bicarinate, the carinae rarely effaced. Frontal carinae absent past frontal lobes. Antennal scrobes absent. Antennae with 11 - 12 segments and with club of 3 (rarely 4) segments. Eyes present, sometimes reduced. Metapleural glands never bulging or hypertrophied. Metapleural lobes usually small, rounded. Propodeum normally unarmed, sometimes angulated to dentate, rarely with lamelliform process. Propodeal spiracle usually circular and at about midlength of the sclerite, rarely in another position. Petiole pedunculated, the petiolar spiracle usually close to or at node. Sting functional.
Nothidris was created by Ettershank (1966) and further delimited by Snelling (1975), who created Antichthonidris to accomodate some species. Bolton (1987: 284 - 285) discussed the traits proposed for the latter, demonstrating their weakness and dubious value as generic-level characters: a vestibulated propodeal spiracle appears to be present in some Australian Monomorium species (Bolton, 1987), for instance, as well as in M. delabiei . Moreover, the inclusion of Antichthonidris in Monomorium , as proposed by Heterick (2001), leaves no justification for maintaining Nothidris as a separate genus.
Phacota has been a taxonomic problem in the myrmicines, due to its poor description, the disappearance of the type specimen, and the lack of collected material referable to P. sichelii (Bolton, 1987) , all of which have impeded an evaluation of its taxonomic status. Ettershank (1966) considered this name a junior synonym of Monomorium . Bolton (1987) subsequently revived the genus, citing the few attributes that can be retrieved from Roger's (1862) original description; nevertheless, he made explicit his strong suspicion that the putative species is based on a wingless, ergatoid Monomorium female, perhaps from the M. salomonis group. Both the meager description (e. g., that the gaster is bigger than the head) and the important fact that the species has not been rediscovered in Spain or any other nearby location, are consistent with this interpretation. Given that the European ant fauna can be considered acceptably collected and studied, and in light of the group's importance, samples assignable to Phacota would surely have been detected and described by now. According to its description, Phacota is characterized by 11 - segmented antennae with a 2 - segmented club. Some Neotropical Solenopsis females possess this combination, but it is an antennal configuration unknown in Monomorium , and it is highly probable that the description of the number of flagellomeres in the antenna and club is erroneous. It would not be the only inadvertent mistake of this type in the history of ant systematics, especially given the size of the ants and the optical resolution possible in the 19 th century. It seems of little practical use to maintain a badlydescribed genus, with no associated type material, and no other collected material, and I recommend that Phacota once again be demoted as proposed by Ettershank (1966) until and unless more material is discovered, or the type specimen (in good condition) reappears.
Epelysidris is a monotypic genus of eastern Malaysia, easily separable by the distinctive pair of lobules on the basal border of each mandible, mandibular and clypeal structure, and palpal formula (Bolton, 1987). Although this taxon is undoubtedly monophyletic, its continued recognition as a separate genus would create the same dilemmas that characterize Antichthonidris , Nothidris , and some others. It is preferable to leave brocha as one additional (although highly apomorphic) species within Monomorium ; I propose here that Epelysidris thus be considered a junior synonym of Monomorium .
Monomorium Mayr,1855: Verh. zool. Bot. Ges. Wien.5:452.
Type-species: Monomorium minutum Mayr , 1855: Verh. Zool. Bot. Ges. Wien.5: 453.
Distribution: Palaearctic, Ethiopian, Oriental, Australian, Polynesian, Nearctic & Neotropical regions.
Key to species
1- Antennae with terminal funiculus segment longer than the two preceeding segments together (Fig.36), unicolourous, body entirely dark black, dorsum of alitrunk without projecting hairs (Fig.37) ........................ ........................ M. carbonarium (Smith)
- Antennae with terminal funiculus segment shorter than the two preceeding segments together (Fig. 38); bicolourous, head, alitrunk, nodes and appendages red, gaster black; dorsum of alitrunk with projecting hairs (Fig. 39)......... M. niloticum Emery
Taxonomy. The genus Monomorium is assigned to the Solenopsis genus group of the tribe Solenopsidini (Bolton 2003). The concept of the genus was revised by Bolton (1987), and was recently widened by Heterick (2003) and Fernández (2007). Workers of Vietnamese species have the following features.
Worker caste monomorphic or polymorphic; head in full-face view subrectangular, with rounded posterior corners; frontal lobe in full-face view narrow, just concealing antennal insertion, not extending posteriorly as a frontal carina, moderately or narrowly separated by posteromedian part of clypeus; antennal scrobe absent; median portion of clypeus expanded anteriad, with a straight anteromedian margin, usually defined laterally by clypeal carinae; median clypeal seta present; mandible narrow; masticatory margin with apical and 2 subapical teeth usually followed by a small or inconspicuous tooth, but sometimes by 1 or 2 distinct teeth (thus the margin 3- to 5-toothed); antenna 11- or 12-segmented, with 3-segmented club; eye medium to small in size (rarely reduced to a single ommatidium); promesonotum in lateral view usually weakly raised; promesonotal suture completely absent dorsally; metanotal suture usually a deeply impressed groove on dorsum; propodeum unarmed, but rarely with posterodorsal angles; propodeal lobe absent or indistinct, but sometimes roundly expanded; petiole pedunculate anteriorly and with distinct node; postpetiole much shorter than petiole, in dorsal view almost as broad as or a little broader than petiolar node; gastral shoulder weak or indistinct, but sometimes well developed; first gastral tergite largely overlapping first gastral sternite.
The worker of Monomorium is similar to those of Anillomyrma (see under Anillomyrma ), Cardiocondyla (see under Cardiocondyla ) and Solenopsis , and to the minor workers of Pheidole and Pheidologeton . However, in the worker of Solenopsis the antennal club is 2-segmented. In the minor of Pheidole the median clypeal seta is absent, the masticatory margin of mandible has 6 or more teeth/denticles, and propodeal spines are usually (but not always) present. In the minor of Pheidologeton the antennal club is 2-segmented, the median clypeal seta is absent, and propodeum is always armed with spines or denticles.
Vietnamese species. Two species have been described from Vietnam: annamense Donisthorpe (type locality: Da Lat) and silvestrii Wheeler (type locality: Yen Bay; other locality: Va n Phu). Ten additional species have been recognized by us from Vietnam: chinense Santschi [= sp. eg-6] (Ba Vi, Cuc Phuong, Tam Dao); floricola (Jerdon) [= sp. eg-7] (Que Phong, Pu Mat); hiten Terayama [= sp. eg-3] (Ba Be, Ba Vi, Cuc Phuong, Tam Dao, Tay Yen Tu, V a n B a n); pharaonis (Linnaeus) [= sp. eg-4] (Ba Be, Ba Vi, Cuc Phuong, Nui Chua, Pu Mat, Quang Tri, Tam Dao); sechellense Emery [= sp. eg-5] (Ba Vi, Binh Chau-Phuoc Buu, Cuc Phuong, Pu Mat); sp. eg-1 [= sp. 9 of SKY: Eguchi et al. 2005] (Ba Vi, Cuc Phuong, Pu Mat, Tam Dao, Tay Yen Tu, Van Ban); sp. eg-2 [= sp. 1 of SKY: Yamane et al., 2003] (Ba Be, Cuc Phuong, Tay Yen Tu); sp. eg-8 (Nam Cat Tien, Phu Quoc, Pu Mat); sp. eg-9 (Nui Chua); sp. eg-10 (Nui Chua, Phu Quoc).
Bionomics. Monomorium species are found in various habitats such as bare lands, grasslands, forest edges and well-developed forests. Their nests are usually found under stones and in soil. Most species forage on the ground, but some, such as M. sechellense , forage both on and under the ground (Eguchi & Bui 2009).
Monomorium is a genus of ants in the subfamily Myrmicinae. As of 2013 it contains about 396 species.[1] It is distributed around the world, with many species native to the Old World tropics.[2] It is considered to be "one of the more important groups of ants," considering its widespread distribution, its diversity, and its variety of morphological and biological characteristics.[3] It also includes several familiar pest species, such as the pharaoh ant (M. pharaonis) and the flower ant (M. floricola).[3]
This genus is very diverse in morphology, with species of many shapes and sizes that "do not necessarily even remotely resemble one another" at first glance.[3]
In certain species, the worker caste is monomorphic, whereas in others, it is polymorphic. In some species the workers are minute, in others they are rather large. Large, multifaceted eyes are common, but M. inusuale has much reduced eyes, as do some species from Africa. The sting is always functional.[4]
By the early 20th century Monomorium was already a large genus, with 10 subgenera.[5] It was further expanded in 2007, when the genera Nothidris, Epelysidris, and Phacota were synonymized with Monomorium. The small genera Anillomyrma, Megalomyrmex, and perhaps Bondroita should possibly also be included in Monomorium.[4]
The exact boundaries of the genus are still to be determined: it has no distinct morphological traits that set it apart from other genera in the tribe Solenopsidini. If cladistics were strictly applied, all Solenopsidini would be grouped in the single genus Solenopsis, but the tribe lacks a strong synapomorphy. As with the genera Camponotus and Leptothorax, Monomorium as it currently stands is paraphyletic.[6]
Subsequent studies using molecular techniques have suggested ways to break up the genus. A 2015 study resurrected the previously-synonomised genus Syllophopsis (including Ireneidris) from within Monomorium. Epelysidris was also resurrected to contain the species E. brocha.[7] In 2019 the genus Chelaner was resurrected for 53 Australasian and Pacific species, including the common New Zealand species Chelaner antipodum.[5]
Most ants of this genus nest in rotting wood, under rocks, or in the soil.[2] Some species are scavengers, while others are seed collectors.[8] Many species have venom containing alkaloids, which they use as a defense from predators.[9] Besides its morphological variation, the genus is also variable in chromosome number, with 2n of 16 to 70 recorded.[10]
As of 2006, 36 species are described from Madagascar, 19 of which were described in that year alone. About 43 species are known from Australia and 30 from Arabia.[6]
Monomorium is a genus of ants in the subfamily Myrmicinae. As of 2013 it contains about 396 species. It is distributed around the world, with many species native to the Old World tropics. It is considered to be "one of the more important groups of ants," considering its widespread distribution, its diversity, and its variety of morphological and biological characteristics. It also includes several familiar pest species, such as the pharaoh ant (M. pharaonis) and the flower ant (M. floricola).
