Polyrhachis

Polyrhachis Temporal range: 7.246–0 Ma K Pa Eo Ol Mi Pl Miocene – Recent
Polyrhachis bihamata
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Formicinae
Tribe:	Camponotini
Genus:	Polyrhachis Smith, F., 1857
Type species
Formica bihamata, now Polyrhachis bihamata
Subgenera
Aulacomyrma Emery, 1921 Campomyrma Wheeler, W.M., 1911 Chariomyrma Forel, 1915 Cyrtomyrma Forel, 1915 Hagiomyrma Wheeler, W.M., 1911 Hedomyrma Forel, 1915 Hemioptica Roger, 1862 Hirtomyrma Kohout, 2010 Myrma Billberg, 1820 Myrmatopa Forel, 1915 Myrmhopla Forel, 1915 Myrmothrinax Forel, 1915 Polyrhachis Smith, F., 1857
Diversity
783 species 1 fossil species (Species Checklist, Species by Country) Polyrhachis bihamata Specimen Label
Synonyms
Cephalomyrma Karavaiev, 1935 Dolichorhachis Mann, 1919 Evelyna Donisthorpe, 1937 Florencea Donisthorpe, 1937 Irenea Donisthorpe, 1938 Johnia Karavaiev, 1927 Morleyidris Donisthorpe, 1944

Evolutionary Relationships

Gigantiops   (1 species) Santschiella   (1 species) Myrmoteras   (41 species) Camponotini Colobopsis   (117 species) Opisthopsis   (20 species) Dinomyrmex   (2 species) Polyrhachis   (783 species) Camponotus   (1,498 species) Calomyrmex   (14 species) Echinopla   (39 species)

Based on Ward et al. 2016.

Rudy Kohout has spent more than 2 decades revising members of this diverse genus. His ongoing publications focus on sets of species placed in species groups. These groups are organized by subgenera. Dorow (1995) presented the first contemporary reorganization of what had previously slowly developed into a messy tangle of poorly organized groups and forms. Kohout's revisions have altered some of Dorow's groupings. This has come about as particular species and groups have been more carefully assessed. There no longer exists any published overview detailing how all the species groups are organized under their respective subgenera. Antwiki does present some of these updated group revisions and species keys (species groups are presented on their respective subgenera for many groups; see the subgenera listed in the taxobox on the right side of this page). A phylogenetic analysis, using molecular sampling, has recently examined the relationships within and between existing groups (Mezger & Moreau 2015, see below). Not all of the groupings are supported by this analysis. Most of the modern taxonomic revisions have been clear in stating that the current groupings are logical constructs largely based on similarities in morphology and are not phylogenetic hypotheses. Both the species groups and subgenera are important considering the current taxonomic state of the genus as a whole.

Photo Gallery

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  Polyrhachis sp. infected by Ophiocordyceps buquetii, in Ghana. (Photo by João P. M. Araújo)

Identification

Bolton (1973) - Worker. Monomorphic, medium to large (4.4 to 14.1 mm) ants belonging to the formicine tribe Camponotini. Antennae 12-segmented, the scapes inserted some distance behind the posterior clypeal margin (usually a distance greater than the basal width of the scape). Palp formula 6,4; mandibles usually with five, rarely with four teeth. Eyes well developed. Pronotum armed with a pair of spines, teeth or tubercles in all species of the Ethiopian region, the propodeum usually armed with two spines, teeth or tubercles, or a pair of ridges, rarely with only a single transverse ridge or completely unarmed. Promesonotal suture usually present (absent from khepra ), the development of the metanotal groove variable. Mesoscutellum very rarely present. In the single species in which the mesoscutellum occurs on the dorsum of the alitrunk, it is not separated from the scutum by a deep impression. Margination of the alitrunk variable, often present and complete but showing all stages through to a fully immarginate condition. Petiole usually with four but occasionally with two or six spines or teeth of variable configuration. Gaster large, globose, the first tergite extensive, usually forming at least half of the dorsal surface. The anterior face of the first gastral tergite is often truncated or concave. Acidopore not borne upon a conical projection of the hypopygium, usually concealed by the pygidium when not in use. Queen. As worker but with the alitrunk massively developed and with a corresponding reduction in armament and margination. The petiolar spines tend to be reduced and are usually smaller than those of the associated worker. Ocelli are present and wing venation is of the usual camponotine form. Male. Very poorly known, in most cases indistinguishable from the males of Camponotus.

Keys including this Genus

• Key to Australian Genera of Formicinae

 

Keys to Species in this Genus

• Key to Australian Polyrhachis Subgenera
• Key to Australian Polyrhachis (Cyrtomyrma) species
• Key to Australian Polyrhachis (Myrmhopla) species
• Key to Australian Polyrhachis (Hirtomyrma) species
• Key to Australian Polyrhachis (Myrma) species
• Key to Australian Polyrhachis (Myrmothrinax) species
• Key to Australian Polyrhachis (Myrmatopa) species
• Key to Polyrhachis (Hemioptica) species
• Key to Australian Polyrhachis (Campomyrma) species
• Key to Polyrhachis (Hagiomyrma) species
• Key to Polyrhachis aculeata group species
• Key to Polyrhachis continua group species
• Key to Polyrhachis (Polyrhachis) species
• Key to Polyrhachis Hagiomyrma group species
• Key to Polyrhachis xiphias group species
• Key to Polyrhachis micans species-group workers
• Key to Polyrhachis gravis species-group workers
• Key to Afrotropical Polyrhachis species (Bolton 1973, OUTDATED)
• Key to Afrotropical Polyrhachis species
• Key to Polyrhachis cyaniventris species-group workers
• Key to Polyrhachis (Aulacomyrma) species
• Key to Afrotropical Polyrhachis species-groups
• Key to Polyrhachis flavoflagellata species-group
• Key to Polyrhachis of the southwestern Australian Botanical Province
• Key to Sulawesi Polyrhachis subgenera and species-groups
• Key to Sulawesi Polyrhachis Cyrtomyrma species
• Key to Sulawesi Polyrhachis relucens-group species
• Key to Polyrhachis vestita-group species
• Key to Polyrhachis flavicornis-group species
• Key to Polyrhachis schang-group species
• Key to Polyrhachis wallacei-group species
• Key to Polyrhachis armata-group species
• Key to Polyrhachis cleophanes-group species
• Key to Polyrhachis mucronata-group species
• Key to Sulawesi Polyrhachis aequalis-group species
• Key to Sulawesi Polyrhachis hector-group species
• Key to Papuasian Polyrhachis Cyrtomyrma species
• Key to Polyrhachis of India
• Key to Polyrhachis Chariomyrma select Australian species
• Key to select Polyrhachis (Campomyrma) of Australian
• Key to Polyrhachis Cyrtomyrma of China and the Indo-China Peninsula
• Key to Polyrhachis Cyrtomyrma of Borneo
• Key to Polyrhachis cryptoceroides-group species
• Key to Polyrhachis parabiotica-group species
• Key to New Guinea Polyrhachis Cyrtomyrma
• Key to Solomon Island Polyrhachis Cyrtomyrma

See the nomenclature section below for links to more Polyhrachis keys.

Distribution

Fossils

Fossils are known from: Varvara Formation, Apomarma, Messara Basin, Crete, Greece (Messinian, Late Miocene).

Biology

Bolton (1973) - The nesting habits of the genus as a whole have been discussed by Hung (1967) who sums up by saying that four types may be recognised, as follows:

1. Arboreal: carton and silk nests amongst leaves and twigs.

2. Lignicolous: nests in the cavities of plants.

3. Terrestrial: nests on the ground under any object.

4. Subterranean: nests in the soil, without cover.

Robson & Kohout (2007) - Based on a review of 197 of the approximately 500 described species of Polyrhachis, the majority of species within a particular subgenus demonstrate a consistent nesting type but a few species can be highly variable, demonstrating both subterranean and arboreal habits. The inclusion of larval silk in the nests is correlated almost entirely with arboreal nesting, but the presence of spider silk in the nests of at least four species suggests caution when inferring silk origin. Pupal cocoons are present in all but subgenera Cyrtomyrma and Myrmatopa.

Africa

Bolton (1973) - All four nesting types (see above) are found in the Ethiopian regional fauna. Obviously, the first on the list is more or less restricted to forest species whilst the third and fourth are most commonly found in savannah forms. The second type listed above is rather a broad category and as far as the Ethiopian region is concerned includes such diverse nest sites as those of Polyrhachis decemdentata in rotten or termite-mined tree branches and those of Polyrhachis cubaensis inside stem galls. It would probably also hold Polyrhachis otleti which nests in rot holes or crevices in tree trunks and covers the entrance with a mesh of silk and vegetable fibres.

The distribution of the species may be divided roughly into forest and savannah forms although some may penetrate the edges of one from the other. The species Polyrhachis viscosa and Polyrhachis schistacea may be considered as typical of the savannah forms, spreading throughout the continent; the former even occurs on the coastal plains of West Africa. Nests are constructed in the earth and the ants are fast-moving, ascending grasses and bushes to forage. The forest species are typified by Polyrhachis militaris and Polyrhachis decemdentata, arboreal retiring forms foraging singly upon the trees and with a marked tendency to release their grip and fall into the undergrowth if disturbed.

Association with Other Organisms

Spider Mimics

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  A Polyrhachis-mimicking spider from Trivandrum, India. Photo by Kalesh Sadasivan.

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  A spider mimic of a member of the subgenus Cyrtomyrma from Cairns, Australia. Photo by Steve Shattuck.

Hymenoptera

• This species is a host for the eucharitid wasp Stilbula arenae (a parasite) (Universal Chalcidoidea Database) (primary host; Polyrhachis sp., Cyrtomyrma sp.).
• This species is a host for the eucharitid wasp Rhipipalloidea sp. (a parasite) (Universal Chalcidoidea Database) (primary host).

Fungi

• Unknown species of Polyrhachis are hosts for the fungi Ophiocordyceps irangiensis, Ophiocordyceps ootakii, Ophiocordyceps myrmecophila and Ophiocordyceps satoi (Araujo et al., 2018; Shrestha et al., 2017).

All Associate Records for Genus

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Taxon	Relationship	Associate Type	Associate Taxon	Associate Relationship	Locality	Source	Notes
Polyrhachis	host	eucharitid wasp	Rhipipalloidea sp.	parasite		Universal Chalcidoidea Database	primary host
Polyrhachis	host	eucharitid wasp	Stilbula arenae	parasite		Universal Chalcidoidea Database	primary host; ''Polyrhachis'' sp., ''Cyrtomyrma'' sp.
Polyrhachis	host	fungus	Ophiocordyceps irangiensis	pathogen		Shrestha et al., 2017
Polyrhachis	host	fungus	Ophiocordyceps myrmecophila	pathogen		Shrestha et al., 2017
Polyrhachis	host	fungus	Ophiocordyceps ootakii	pathogen		Araujo et al., 2018
Polyrhachis	host	fungus	Ophiocordyceps satoi	pathogen		Araujo et al., 2018
Polyrhachis armata	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis bellicosa	host	cricket	Myrmecophilus polyrhachi	myrmecophile	Gombak, Malaysia
Polyrhachis debilis	host	fungus	Ophiocordyceps unilaterialis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis decemdentata	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis dives	host	eucharitid wasp	Stilbula polyrhachicida	parasite		Universal Chalcidoidea Database	primary host
Polyrhachis dives	host	fungus	Ophiocordyceps unilaterialis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis femorata	host	eucharitid wasp	Rhipipalloidea mira	parasite		Universal Chalcidoidea Database	primary host
Polyrhachis fissa	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis furcata	host	fungus	Ophiocordyceps polyrhachis-furcata	pathogen		Araujo et al., 2018
Polyrhachis furcata	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis hippomanes	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis illaudata	host	fungus	Ophiocordyceps unilaterialis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis laboriosa	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis lama	inquiline	ant	Diacamma sp.
Polyrhachis lamellidens	host	''Microdon'' fly	Microdon piperi	predator	Oregon, Montana, Washington (type)	Knab, 1917
Polyrhachis lamellidens	host	fungus	Ophiocordyceps unilateralis var. clavata	pathogen		Shrestha et al., 2017
Polyrhachis lamellidens	temporary parasite	ant	Camponotus japonicus	host		Kohriba, 1963
Polyrhachis lamellidens	temporary parasite	ant	Camponotus kiusiuensis	host		Sakai, 1990	Needs confirmation
Polyrhachis lamellidens	temporary parasite	ant	Camponotus obscuripes	host		Sakai, 1990
Polyrhachis latharis	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis latispina	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis latona	host	fungus	Ophiocordyceps unilaterialis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis militaris	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis monista	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis proxima	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis revoili	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis robsoni	host	fungus	Ophiocordyceps naomipierceae	pathogen		Araujo et al., 2018	identity of ant species uncertain
Polyrhachis rufofemorata	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis schellerichae	mutualist	mealybug	Kermicus wroughtoni	trophobiont		Schellerich-Kaaden et al. 1997
Polyrhachis sulcata	host	fungus	Ophiocordyceps unilaterialis	pathogen		Shrestha et al., 2017
Polyrhachis vigilans	host	fungus	Ophiocordyceps unilaterialis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis wolfi	host	fungus	Ophiocordyceps unilaterialis	pathogen	Taiwan	Lin et al., 2020

Phylogeny

(Mezger & Moreau 2015) Spiny ants (Polyrhachis Smith) are a hyper-diverse genus of ants distributed throughout the Palaeotropics and the temperate zones of Australia. To investigate the evolution and biogeographic history of the group, we reconstructed their phylogeny and biogeography using molecular data from 209 taxa and seven genes. Our molecular data support the monophyly of Polyrhachis at the generic level and several of the 13 recognized subgenera, but not all are recovered as monophyletic. We found that Campomyrma Wheeler consists of two distinct clades that follow biogeographic affinities, that the boundaries of Hagiomyrma Wheeler are unclear depending on the analysis, that Myrma Billberg might be treated as one or two clades, and that Myrmhopla Forel is not monophyletic, as previously proposed. Our biogeographic ancestral range analyses suggest that the evolution of Polyrhachis originated in South-East Asia, with an age of the modern crown-group Polyrhachis of 58 Ma. Spiny ants dispersed out of South-East Asia to Australia several times, but only once to mainland Africa around 26 Ma.

Morphology

Worker Morphology

• Antennal segment count: 12
• Antennal club: absent-gradual
• Palp formula: 6,4
• Total dental count: 5-6
• Spur formula: 1 simple-pectinate, 1 simple-pectinate; 0, 0
• Eyes: present
• Scrobes: absent
• Sting: absent

Karyotype

Species Uncertain

• Polyrhachis sp.(ANIC-1): 2n = 42 (Australia) (Imai et al., 1977).
• Polyrhachis sp.1: n = 21 (Malaysia) (Goni et al., 1982).
• Polyrhachis sp.2: n = 21 (Malaysia) (Goni et al., 1982).
• Polyrhachis sp.3: 2n = 20 (Malaysia) (Goni et al., 1982).

All Karyotype Records for Genus

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Taxon	Haploid	Diploid	Karyotype	Locality	Source	Notes
Polyrhachis		20		Malaysia	Goni et al., 1982
Polyrhachis		42		Australia	Imai et al., 1977
Polyrhachis	21			Malaysia	Goni et al., 1982
Polyrhachis ammon	21	42		Australia	Imai et al., 1977
Polyrhachis dives	21		1M+8SM+1ST+3A+8T	Taiwan	Hung et al., 1972
Polyrhachis gribodoi		48		Indonesia	Imai et al., 1985
Polyrhachis hector	21	42		Malaysia	Imai et al., 1983
Polyrhachis hippomanes	20	40		Japan	Imai, 1969
Polyrhachis illaudata	14	28		Indonesia	Imai et al., 1985
Polyrhachis illaudata	18			Malaysia	Imai et al., 1983
Polyrhachis lacteipennis		42	6M+36A	India	Imai et al., 1984	as ''Polyrhachis simplex''
Polyrhachis lamellidens		42		Japan	Imai, 1969
Polyrhachis rastellata	21	42	8M+34SM	Malaysia	Crozier, 1970b; Imai et al., 1983

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• POLYRHACHIS [Formicinae: Camponotini]
  • Polyrhachis Smith, F. 1857a: 58. Type-species: Formica bihamata, by original designation.
  • [Polyrhachis Shuckard, in Swainson & Shuckard, 1840: 172. Nomen nudum.]
  • Polyrhachis subgenus of Myrma: Wheeler, W.M. 1911c: 860; Wheeler, W.M. 1911f: 170.
  • [Myrma subgenus of Polyrhachis: Forel, 1915b: 106; Forel, 1917: 251; Wheeler, W.M. 1922a: 702, 993; Emery, 1925b: 198 (see note under Myrma).]
  • Subgenera of Polyrhachis (alphabetical order with synonyms indicated): nominal plus Aulacomyrma (= Johnia), Campomyrma, Chariomyrma, Cyrtomyrma, Hagiomyrma, Hedomyrma (= Dolichorhachis, = Morleyidris), Hemioptica, Hirtomyrma, Myrma (= Anoplomyrma, = Hoplomyrmus, = Pseudocyrtomyrma), Myrmatopa (= Irenea), Myrmhopla (= Cephalomyrma, = Florencea), Myrmothrinax (= Evelyna).
  • [All subgenera were given as provisional junior synonyms of Polyrhachis by Brown, 1973b: 178-184. The list was repeated in Hölldobler & Wilson, 1990: 19 with all subgenera listed as junior synonyms. They reverted to subgeneric status in Bolton, 1994: 50; see under individual entries. The entry of Chariomyrma, Hagiomyrma and Hedomyrma under the synonymy of Polyrhachis by Taylor & Brown, D.R. 1985: 131, is not considered as confirmation as the three subgenera all range outside the Austral Region.]
• Polyrachis Arnold, 1924: 741, incorrect subsequent spelling.

Dorow (1995) provides the latest revision of the species into subgenera and species-groups. These hierarchical arranged names are not supported by any strong evidence that these groups between the genus and species level represent monophyletic units. Regardless, much of the framework for these names has been in place for some time and they do serve as a welcome convenience for organizing the complex diversity of species. Rudy Kohout has been revising species by geographic areas and within specific subgenera and species-groups for more than two decades. Kohout's ongoing taxonomic work has largely followed the arrangement of Dorow (1995) with some modifications becoming necessary as more species have been described.

Aulacomyrma - key to Polyrhachis (Aulacomyrma) species

• Polyrhachis porcata species-group
• Polyrhachis dohrni species-group

Campomyrma

• The gravis species-group and a key to species.
• The micans species-group and a key to species.
• The xiphias species-group and a key to species.

Chariomyrma

Cyrtomyrma - key to Australian Cyrtomyrma species

Hagiomyrma - key to Polyrhachis Hagiomyrma group species

Hedomyrma

Hemioptica - species key

Hirtomyrma

Myrma

Myrmatopa

Myrmhopla

Myrmothrinax

Polyrhachis

• Key to the subgenus Polyrhachis workers (includes lamellidens and bihamata species-groups)

References

• Agosti, D. 1991. Revision of the oriental ant genus Cladomyrma, with an outline of the higher classification of the Formicinae (Hymenoptera: Formicidae). Syst. Entomol. 16: 293-310. (page 295, Polyrhachis in Formicinae, Formica genus group)
• Araújo, J.P.M., Evans, H.C., Kepler, R., Hughes, D.P. 2018. Zombie-ant fungi across continents: 15 new species and new combinations within Ophiocordyceps. I. Myrmecophilous hirsutelloid species. Studies in Mycology 90: 119–160 (DOI 10.1016/j.simyco.2017.12.002).
• Arnold, G. 1924. A monograph of the Formicidae of South Africa. Part VI. Camponotinae. Ann. S. Afr. Mus. 14: 675-766 (page 741, Polyrhachis in Camponotinae, Camponotini; [Polyrachis Arnold, 1924: 741, incorrect subsequent spelling].)
• Ashmead, W. H. 1905c. A skeleton of a new arrangement of the families, subfamilies, tribes and genera of the ants, or the superfamily Formicoidea. Can. Entomol. 37: 381-384 (page 384, Polyrhachis in Camponotinae, Polyrhachidini)
• Blanchard, B.D., Nakamura, A., Cao, M., Chen, S.T., Moreau, C.S. 2020. Spine and dine: A key defensive trait promotes ecological success in spiny ants. Ecolology and Evolution 00:1–12 (doi:10.1002/ece3.6322).
• Bolton, B. 1973b. The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae). Bull. Br. Mus. (Nat. Hist.) Entomol. 28: 283-369 (page 289, Key to Afrotropical species)
• Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 123, Polyrhachis in Formicinae, Camponotini; [All subgenera were given as provisional junior synonyms of Polyrhachis by Brown, 1973b: 178-184. The list was repeated in Hölldobler & Wilson, 1990: 19 with all subgenera listed as junior synonyms. They reverted )
• Brown, W. L., Jr. 1973b. A comparison of the Hylean and Congo-West African rain forest ant faunas. Pp. 161-185 in: Meggers, B. J., Ayensu, E. S., Duckworth, W. D. (eds.) Tropical forest ecosystems in Africa and South America: a comparative review. Wash (page 178-184, All subgenera given as provisional junior synonyms of Polyrhachis (unconfirmed).)
• Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 257, Polyrhachis in Camponotinae)
• Dorow, W. H. O. 1995. Revision of the ant genus Polyrhachis Smith, 1857 (Hymenoptera: Formicidae: Formicinae) on subgenus level with keys, checklist of species and bibliography. Cour. Forschungsinst. Senckenb. 185: 1-113 (page 1, Revision of subgenera)
• Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 772, Polyrhachis in Camponotinae, Camponotini)
• Emery, C. 1925d. Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum 183: 1-302 (page 175, Polyrhachis in Formicinae, Camponotini)
• Forel, A. 1878c. Études myrmécologiques en 1878 (première partie) avec l'anatomie du gésier des fourmis. Bull. Soc. Vaudoise Sci. Nat. 15: 337-392 (page 367, Polyrhachis in Camponotinae [Camponotidae])
• Forel, A. 1886h. Études myrmécologiques en 1886. Ann. Soc. Entomol. Belg. 30: 131-215 (page 194, Polyrhachis in Camponotinae, Camponotini)
• Forel, A. 1893b. Sur la classification de la famille des Formicides, avec remarques synonymiques. Ann. Soc. Entomol. Belg. 37: 161-167 (page 165, Polyrhachis in Camponotinae, Camponotini)
• Forel, A. 1912j. Formicides néotropiques. Part VI. 5me sous-famille Camponotinae Forel. Mém. Soc. Entomol. Belg. 20: 59-92 (page 89, Polyrhachis in Camponotinae, Camponotini)
• Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 251, Polyrhachis in Camponotinae, Camponotini)
• Hung, A. C. F. 1967b. A revision of the ant genus Polyrhachis at the subgeneric level (Hymenoptera: Formicidae). Trans. Am. Entomol. Soc. 93: 395-422 (page 395, Revision of subgenera)
• Mayr, G. 1862. Myrmecologische Studien. Verh. K-K. Zool.-Bot. Ges. Wien 12: 649-776 (page 652, Polyrhachis in Formicinae [Formicidae])
• Mayr, G. 1865. Formicidae. In: Reise der Österreichischen Fregatte "Novara" um die Erde in den Jahren 1857, 1858, 1859. Zoologischer Theil. Bd. II. Abt. 1. Wien: K. Gerold's Sohn, 119 pp. (page 6, Polyrhachis in Formicinae [Formicidae])
• Mezger, D. and Moreau, C. S. 2015. Out of South-East Asia: phylogeny and biogeography of the spiny ant genus Polyrhachis Smith (Hymenoptera: Formicidae). Systematic Entomology. 41:369–378. doi:10.1111/syen.12163
• Ramalho, M.O., Bueno, O.C., Moreau, C.S. 2017. Microbial composition of spiny ants (Hymenoptera: Formicidae: Polyrhachis) across their geographic range. BMC Evolutionary Biology 17(1): 96 (doi:10.1186/s12862-017-0945-8).
• Robson, S., Kohout, R. 2007. A review of nesting habits and socioecology of the ant genus Polyrhachis Smith. Asian Myrmecology 1(1): 81-99.
• Robson, S. K. A.; Kohout, R. J.; Beckenbach, A. T.; Moreau, C. S. 2015. Evolutionary transitions of complex labile traits: silk weaving and arboreal nesting in Polyrhachis ants. Behavioral Ecology and Sociobiology 69:449-458.
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• Smith, F. 1858a. Catalogue of hymenopterous insects in the collection of the British Museum. Part VI. Formicidae. London: British Museum, 216 pp. (page 58, Polyrhachis in Formicidae)
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• Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 144, Polyrhachis in Camponotinae, Camponotini)
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• Wheeler, W. M. 1922i. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VII. Keys to the genera and subgenera of ants. Bull. Am. Mus. Nat. Hist. 45: 631-710 (page 701, Polyrhachis in Formicinae, Camponotini)
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• Wheeler, W. M. 1911c. Three formicid names which have been overlooked. Science (N. Y.) (n.s.) 33: 858-860 (page 860, Polyrhachis subgenus of Myrma)
• Wheeler, W. M. 1922j. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bull. Am. Mus. Nat. Hist. 45: 711-1004 (page 993, Myrma subgenus of Polyrhachis)