Polyrhachis

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Polyrhachis
Temporal range: 7.246–0 Ma 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
Diversity
793 species
1 fossil species
(Species Checklist, Species by Country)

Polyrhachis bihamata casent0010659 profile 1.jpg

Polyrhachis bihamata

Polyrhachis bihamata casent0010659 dorsal 1.jpg

Specimen Label

Synonyms

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

  • Polyrhachis Shattuck 52538 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 52551 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 52650 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 52661 Danum Valley Sabah-web.jpg
  • Shattuck N2-5660-web, Polyrhachis rufifemur, near Bungendore, NSW.jpg
  • Polyrhachis Shattuck 52949 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 53002 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 53009 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 53048 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 53065 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 53179 Danum Valley Sabah-web.jpg
  • Polyrhachis Shattuck 53795 ANIC32-066473 Danum Valley Sabah-web.jpg
  • Polyrhachis, India, Vinay Krishnan.jpg
  • Shattuck C16732-1, ANIC32-030579, Polyrhachis, Cairns, Queensland.jpg
  • 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

 

Keys to Species in this Genus

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

Distribution

Distribution and Richness based on AntMaps

Species by Region

Number of species within biogeographic regions, along with the total number of species for each region.

Afrotropical Region Australasian Region Indo-Australian Region Malagasy Region Nearctic Region Neotropical Region Oriental Region Palaearctic Region
Species 63 171 503 0 0 0 129 59
Total Species 2840 1735 3042 932 835 4378 1740 2862

Fossils

Fossils are known from: Varvara Formation, Apomarma, Messara Basin, Crete, Greece (Messinian, Late Miocene), Zhangpu amber, Zhangpu County, Fujian Province, China (Miocene) (an unidentified species, Wang et al., 2021).

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

Explore-icon.png Explore: Show all Associate data or Search these data. See also a list of all data tables or learn how data is managed.

Spider Mimics

Diptera

  • This species is a prey for the Microdon fly Microdon waterhousei (a predator) (Quevillon, 2018).

Hymenoptera

  • This species is a host for the eucharitid wasp Rhipipalloidea sp. (a parasitoid) (Quevillon, 2018) (multiple encounter modes; direct transmission; transmission outside nest).
  • This species is a host for the eucharitid wasp Rhipipalloidea sp. (a parasite) (Universal Chalcidoidea Database) (primary host).
  • This species is a host for the eucharitid wasp Stilbula arenae (a parasitoid) (Quevillon, 2018) (multiple encounter modes; direct transmission; transmission outside nest).
  • This species is a host for the eucharitid wasp Stilbula arenae (a parasite) (Universal Chalcidoidea Database) (primary host; Polyrhachis sp., Cyrtomyrma sp.).

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).
  • This species is a host for the fungus Aspergillus flavus (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission within nest).
  • This species is a host for the fungus Ophiocordyceps irangiensis (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
  • This species is a host for the fungus Ophiocordyceps myrmecophila (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
  • This species is a host for the fungus Ophiocordyceps ootaki (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
  • This species is a host for the fungus Ophiocordyceps satoi (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
  • This species is a host for the fungus Ophiocordyceps sp. (GH 41) (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
  • This species is a host for the fungus Ophiocordyceps unilateralis (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).

All Associate Records for Genus

Click here to show/hide associate data.
Taxon Relationship Associate Type Associate Taxon Associate Relationship Locality Source Notes
Polyrhachis abdominalis host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis abdominalis host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis bellicosa host cricket Myrmecophilus polyrhachi myrmecophile Gombak, Malaysia
Polyrhachis bellicosa host phorid fly Megaselia holosericei parasite Brown et al., 2015 injured
Polyrhachis bellicosa host phorid fly Megaselia sp. parasite Brown et al., 2015 injured
Polyrhachis bellicosa host phorid fly Megaselia sp. parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bihamata host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bihamata host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis calypso host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis debilis host fungus Ophiocordyceps unilateralis pathogen Taiwan Lin et al., 2020
Polyrhachis decemdentata host fungus Akanthomyces gracilis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis decemdentata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis decemdentata host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis delecta host nematode Mermithidae (unspec.) parasite Australia (N. Queensland) Downes, 2017; Laciny, 2021
Polyrhachis dives host eucharitid wasp Stilbula polyrachicida parasitoid Quevillon, 2018 multiple encounter modes; direct transmission; transmission outside nest
Polyrhachis dives host eucharitid wasp Stilbula polyrhachicida parasite Universal Chalcidoidea Database primary host
Polyrhachis dives host eucharitid wasp Stilbuloida doddi parasitoid Quevillon, 2018 multiple encounter modes; direct transmission; transmission outside nest
Polyrhachis dives host fungus Ophiocordyceps unilateralis pathogen Taiwan Lin et al., 2020
Polyrhachis exercita prey tiger beetle Cicindela flavomaculata predator Western Ghats, India Sinu et al., 2006
Polyrhachis exercita prey tiger beetle Cicindela whithilli predator Western Ghats, India Sinu et al., 2006
Polyrhachis femorata host eucharitid wasp Rhipipalloidea mira parasite Universal Chalcidoidea Database primary host
Polyrhachis fissa host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis fissa host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis furcata host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis halidayi host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis halidayi host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis halidayi host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis halidayi host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hauxwelli host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hauxwelli host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hauxwelli mutualist aphid Aphis craccivora trophobiont Rakhshan and Ahmad, 2015; Saddiqui et al., 2019
Polyrhachis hauxwelli prey tiger beetle Cicindela flavomaculata predator Western Ghats, India Sinu et al., 2006
Polyrhachis hauxwelli prey tiger beetle Cicindela whithilli predator Western Ghats, India Sinu et al., 2006
Polyrhachis hippomanes host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hippomanes host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hippomanes host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hippomanes host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis illaudata host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata host fungus Ophiocordyceps unilateralis pathogen Taiwan Lin et al., 2020
Polyrhachis illaudata host milichiid fly Milichia sp. myrmecophile Malaysia Yusah & Fayle, 2014; Milichiidae online
Polyrhachis illaudata host phorid fly Megaselia holosericei parasite Brown et al., 2015 injured
Polyrhachis laboriosa host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis laboriosa host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis lacteipennis mutualist aphid Aphis craccivora trophobiont Shiran et al., 2013; Saddiqui et al., 2019
Polyrhachis lacteipennis mutualist aphid Aphis frangulae trophobiont Shiran et al., 2013; Saddiqui et al., 2019
Polyrhachis lacteipennis mutualist aphid Chaitophorous populialbae trophobiont Degen et al., 1986; Saddiqui et al., 2019 as ''Polyrhachis simplex''
Polyrhachis lacteipennis mutualist aphid Rhopalosiphum maidis trophobiont Shiran et al., 2013; Saddiqui et al., 2019
Polyrhachis lama inquiline ant Diacamma sp. Maschwitz et al., 2000
Polyrhachis lamellidens host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis lamellidens host fungus Ophiocordyceps unilateralis var. clavata pathogen Shrestha et al., 2017
Polyrhachis lamellidens prey ''Microdon'' fly Microdon katsurai predator Quevillon, 2018
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 unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis latharis host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis latispina host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis latispina host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis latona host fungus Ophiocordyceps unilateralis pathogen Taiwan Lin et al., 2020
Polyrhachis militaris host fungus Akanthomyces gracilis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis militaris host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis militaris host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis monista host fungus Akanthomyces gracilis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis monista host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis monista host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis monteithi host nematode Mermithidae (unspec.) parasite Australia (N. Queensland) Downes, 2017; Laciny, 2021
Polyrhachis proxima host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima host fungus Ophiocordyceps irangiensis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis rastellata host fungus Ophiocordyceps formicarum parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis rastellata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis revoili host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis revoili host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis robsoni host fungus Ophiocordyceps myrmecophila parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis robsoni host fungus Ophiocordyceps naomipierceae parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis robsoni host fungus Ophiocordyceps naomipierceae pathogen Araujo et al., 2018 identity of ant species uncertain
Polyrhachis robsoni host fungus Ophiocordyceps pseudolloydii parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis rufofemorata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis rufofemorata host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis schellerichae mutualist mealybug Kermicus wroughtoni trophobiont Schellerich-Kaaden et al. 1997
Polyrhachis sulcata host fungus Ophiocordyceps unilateralis parasitoid Quevillon, 2018 encounter mode primary; direct transmission; transmission outside nest
Polyrhachis sulcata host fungus Ophiocordyceps unilateralis pathogen Shrestha et al., 2017
Polyrhachis vigilans host fungus Ophiocordyceps unilateralis pathogen Taiwan Lin et al., 2020
Polyrhachis wolfi host fungus Ophiocordyceps unilateralis pathogen Taiwan Lin et al., 2020

Flight Period

All Flight Records for Genus

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Taxon Month Source Notes
Polyrhachis lamellidens Sep Oct Nov

Life History Traits

  • Mean colony size: 60-878096 (Greer et al., 2021)
  • Compound colony type: temperary parasite; xenobiosis? (Greer et al., 2021)
  • Nest site: hypogaeic; arboreal (Greer et al., 2021)
  • Diet class: omnivore (Greer et al., 2021)
  • Foraging stratum: subterranean/leaf litter; arboreal (Greer et al., 2021)

Castes

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

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• 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: >100 ommatidia • Scrobes: absent • Pronotal Spines: dentiform; present • Mesonotal Spines: absent • Propodeal Spines: dentiform; present • Petiolar Spines: dentiform; present • Caste: none or weak • Sting: absent • Metaplural Gland: absent • Cocoon: polymorphic

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 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

Phylogeny

Formicinae
Myrmelachistini
Lasiini
Melophorini
Formicini
Gesomyrmecini

Gesomyrmex  (7 species, 12 fossil species)

Oecophyllini

Oecophylla  (15 species, 16 fossil species)

Plagiolepidini
Gigantiopini

Gigantiops  (1 species, 0 fossil species)

Santschiellini

Santschiella  (1 species, 0 fossil species)

Myrmoteratini

Myrmoteras  (41 species, 0 fossil species)

Camponotini

See Phylogeny of Formicinae for details.

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

Campomyrma

Chariomyrma

Cyrtomyrma - key to Australian Cyrtomyrma species

Hagiomyrma - key to Polyrhachis Hagiomyrma group species

Hedomyrma

Hemioptica - species key

Hirtomyrma

Myrma

Myrmatopa

Myrmhopla

Myrmothrinax

Polyrhachis

References

yrhachis)