Cheliomyrmex

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Cheliomyrmex
Cheliomyrmex morosus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Cheliomyrmex
Mayr, 1870
Type species
Cheliomyrmex nortoni (junior synonym of Cheliomyrmex morosus)
Diversity
4 species
(Species Checklist)

Cheliomyrmex morosus casent0003202 profile 1.jpg

Cheliomyrmex morosus

Cheliomyrmex morosus casent0003202 dorsal 1.jpg

Specimen Label

Evolutionary Relationships
Dorylinae

Eburopone
  (1 species)



Simopone
  (39 species)



Tanipone
  (10 species)



Vicinopone
  (1 species)




Cerapachys
  (5 species)



Chrysapace
  (3 species)



Yunodorylus
  (4 species)





Eusphinctus
  (2 species)



Ooceraea
  (11 species)



Syscia
  (5 species)





Lioponera
  (74 species)




Lividopone
  (1 species)




Parasyscia
  (50 species)



Zasphinctus
  (23 species)







Aenictus
  (215 species)




Aenictogiton
  (7 species)



Dorylus
  (127 species)






Neocerapachys
  (2 species)




Acanthostichus
  (23 species)



Cylindromyrmex
  (10 species)





Leptanilloides
  (19 species)



Sphinctomyrmex
  (3 species)




Neivamyrmex
  (129 species)




Cheliomyrmex
  (4 species)




Labidus
  (9 species)




Eciton
  (29 species)



Nomamyrmex
  (2 species)









Based on Ward et al. (2014), Borowiec (2016).

Cheliomyrmex is a rarely encountered genus of New World army ants that is a mostly subterranean predator with likely a specialized diet.

Identification

Borowiec (2016) - Worker Workers of Cheliomyrmex can be recognized by a combination of propodeal spiracle positioned high on the propodeum, propodeal declivity simple and not armed with cuticular ridges or denticles, abdominal segment III small but broad posteriorly and thus waist appearing one-segmented, pygidium small and armed with at most a pair of modified setae, and pretarsal claws armed with a tooth. Cheliomyrmex is perhaps most similar to Labidus and certain Neivamyrmex but it is unique among New World army ants in having abdominal segment III broadly attached to segment IV (i.e. it has a uninodal waist) and thus easily told apart from all other army ant genera in this region.

Male The males of Cheliomyrmex share the following wing venation characters with other New World army ants (Eciton, Labidus, Neivamyrmex and Nomamyrmex): costal (C) vein present in the fore wing, relatively narrow pterostigma, presence of vein 2rs-m and two closed submarginal cells, marginal cell closed by R·f3 and Rs·f4–5, 2rs-m present, and M·f1 vein arising from M+Cu at an angle lower than 45° and conspicuously proximal to cu-a. This characteristic venation pattern serves to distinguish New World army ants from the Old World army ants (Aenictogiton, Aenictus, Dorylus) that have no vein R·f3 and where M·f1 arises near cu-a and at an angle close to or higher than 45°. Aenictus and Dorylus additionally have no vein Rs·f2–3 and so only one submarginal cell that is closed distally by 2rs-m. In other dorylines with well-developed wing venation (e.g. Chrysapace, Cylindromyrmex) the vein M·f1 arises distal to cu-a and pterostigma is very broad and conspicuous. Within the New World army ants, wing venation is relatively conserved and thus of little use in discrimination of genera. Genitalic characters have been found to be the most reliable (Watkins 1976), although impossible to ascertain without dissection. A combination of absence of very long setae approaching femur length on the abdomen, apices of penisvalvae with setae, and the sternite of abdominal segment IX (subgenital plate) with four teeth, and a simple hind basitarsus will distinguish Cheliomyrmex males from all other army ant genera in the New World. The long setae on gaster are characteristic of Nomamyrmex. The penisvalvae with setae are also present in Labidus but the latter can be told apart by having only two teeth on the abdominal sternite IX and a complex hind basal tarsal segment, which has a conspicuous oblique groove that accommodates the hind tibial spur.

Keys including this Genus

Distribution

Cheliomyrmex is present in most of Central America, including southern Mexico, Belize, Guatemala, Honduras, and Panama, but so far it has not been collected in Nicaragua or Costa Rica. It is also known from northern and northwestern South America south to Peru and Bolivia. (Borowiec 2016)

World distribution based on political regions. View/Edit Data
Cheliomyrmex Distribution.png Worlddistribution legend.jpg

Species richness

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

Cheliomyrmex Species Richness.png

Biology

Ants in this lineage have been rarely observed or collected. The raids and emigrations of these ants are mostly subterranean, only occasionally seen above ground. Raids have been observed mostly under stones or rotting wood (Wheeler 1921, Gotwald 1971). A diverse fauna of associates was reported from an emigration column of Cheliomyrmex morosus, including phorid flies, staphylinid beetles, silverfish and mites (Berghoff and Franks 2007). The 2007 study and the only other published observation of a Cheliomyrmex emigration (Cheliomyrmex megalonyx; Wheeler 1921), described galleries of soil built by the ants to cover the areas where the ant columns had to proceed on the surface. Wheeler also reported a behavior where stationary major workers were guarding the emigration columns and compared it to that of African Dorylus, although this behavior is also known in Labidus (Rettenmeyer 1963). As Wheeler observed only larvae being carried by the workers, it has been postulated that brood production is synchronized (Rettenmeyer 1963). Cheliomyrmex andicola has been observed feeding on a dead snake and actively pursuing and killing a giant earthworm in Ecuador (O’Donnell et al. 2005). Given that no other prey has been observed for this genus, combined with the specialized mandibular morphology and potent sting, O’Donnell et al. (2005) proposed that Cheliomyrmex are specialized predators of large subterranean invertebrates or maybe even vertebrates.

Castes

Morphology

Worker Morphology

 • Antennal segment count 12 • Antennal club absent • Palp formula 2,3 • Total dental count 2-18(0-5) • Spur formula 1 pectinate, 1 pectinate • Eyes present • Scrobes absent • Caste polymorphic • Sting present

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • CHELIOMYRMEX [Ecitoninae: Cheliomyrmecini]
    • Cheliomyrmex Mayr, 1870b: 968. Type-species: Cheliomyrmex nortoni (junior synonym of Labidus morosus), by monotypy.

Borowiec (2016) - Cheliomyrmex was introduced by Mayr in 1870 who described Cheliomyrmex nortoni, now a junior synonym of Cheliomyrmex morosus (Smith 1859) and recognized its affinity to other dorylines. The genus-level taxonomy of Cheliomyrmex has been relatively stable and there are four currently recognized species. Because of its morphology, notably the fact that Cheliomyrmex are the only New World army ants that possess only a single waist segment, the genus has been often considered of particular importance to army ant systematics (Wheeler 1921, Gotwald 1971, Gotwald and Kupiec 1975, Gotwald 1979). However, the current understanding of doryline phylogeny shows Cheliomyrmex nested within the New World army ants (Brady et al. 2014), sister to the (Labidus (Eciton plus Nomamyrmex)) clade.

Worker

Borowiec (2016) - Head: Antennae with 12 segments. Apical antennal segment not enlarged, not broader and longer than two preceding segments combined. Clypeus without cuticular apron. Lateroclypeal teeth absent. Parafrontal ridges reduced. Torulo-posttorular complex vertical. Antennal scrobes absent. Labrum with median notch or concavity. Proximal face of stipes not projecting beyond inner margin of sclerite, prementum exposed when mouthparts fully closed. Maxillary palps 2-segmented. Labial palps 3-segmented. Mandibles polymorphic, from triangular with teeth through triangular with median tooth to falcate, with teeth on elongated masticatory margin. Eyes present, composed of 1–5 ommatidia. Ocelli absent. Head capsule with differentiated vertical posterior surface above occipital foramen. Ventrolateral margins of head without lamella or ridge extending towards mandibles and beyond carina surrounding occipital foramen. Posterior head corners dorsolaterally immarginate. Carina surrounding occipital foramen ventrally absent. Mesosoma: Pronotal flange not separated from collar by distinct ridge. Promesonotal connection with suture completely fused. Pronotomesopleural suture visible, unfused partway to notal surface. Mesometapleural groove weakly impressed. Transverse groove dividing mesopleuron present. Pleural endophragmal pit concavity present. Mesosoma dorsolaterally immarginate. Metanotal depression or groove on mesosoma present. Propodeal spiracle situated high on sclerite. Propodeal declivity without distinct dorsal edge or margin and rectangular in posterior view. Metapleural gland with bulla visible through cuticle. Propodeal lobes absent. Metasoma: Petiole anterodorsally immarginate, dorsolaterally immarginate, and laterally above spiracle marginate. Helcium in relation to tergosternal suture placed at suture and infraaxial. Prora narrowed into anteriorly directed spine. Spiracle openings of abdominal segments IV–VI oval. Abdominal segment III anterodorsally immarginate and dorsolaterally immarginate. Abdominal segment III more than half size of succeeding segment IV, which is weakly constricted at presegmental portion (uninodal waist). Girdling constriction of segment IV present, i.e. pre- and postsclerites distinct. Cinctus of abdominal segment IV gutter-like, not sculptured. Abdominal segment IV not conspicuously largest segment. Abdominal tergite IV not folding over sternite, and anterior portions of sternite and tergite equally well visible in lateral view. Girdling constriction between pre- and posttergites of abdominal segments V and VI absent. Girdling constriction between pre- and poststernites of abdominal segments V and VI absent. Pygidium small, reduced to narrow strip, without impressed medial field, and simple, not armed with cuticular spines or modified setae. Hypopygium unarmed. Legs: Mid tibia with single pectinate spur. Hind tibia with single pectinate spur. Hind basitarsus not widening distally, circular in cross-section. Posterior flange of hind coxa not produced as raised lamella. Metatibial gland present as oval patch of whitish cuticle. Metabasitarsal gland absent. Hind pretarsal claws each armed with a tooth. Polymorphism: Polymorphic.

Male

Borowiec (2016) - Head: Antennae with 13 segments. Clypeus without cuticular apron. Parafrontal ridges absent. Torulo-posttorular complex vertical. Maxillary palps 2-segmented. Labial palps 3-segmented. Mandibles falcate. Ventrolateral margins of head without lamella or ridge extending towards mandibles and beyond carina surrounding occipital foramen. Carina surrounding occipital foramen ventrally absent. Mesosoma: Pronotal flange not separated from collar by distinct ridge. Notauli absent. Transverse groove dividing mesopleuron absent. Propodeal declivity reduced, without distinct dorsal edge or margin. Metapleural gland opening absent. Propodeal lobes absent. Metasoma: Petiole anterodorsally immarginate, dorsolaterally immarginate, and laterally above spiracle immarginate. Helcium in relation to tergosternal suture placed at suture and axial. Prora simple, not delimited by carina. Spiracle openings of abdominal segments IV–VI slit-shaped. Abdominal segment III more than half size of succeeding segment IV; latter weakly constricted at presegmental portion (uninodal waist). Girdling constriction of segment IV absent, i.e. pre- and postsclerites indistinct. Cinctus of abdominal segment IV absent, not impressed. Girdling constriction between pre-and postsclerites of abdominal segments V and VI absent. Abdominal segment IV not conspicuously largest segment. Abdominal sternite VII simple. Abdominal sternite IX distally armed with two outer spines and additional two inner denticles, with lateral apodemes longer than much reduced medial apodeme, directed anteriorly (towards head). Genitalia: Cupula very long, nearing or surpassing length of rest of genital capsule and shorter ventrally than dorsally. Basimere narrowly fused to telomere, with sulcus visible at least partway through junction, and ventrally with left and right arms abutting. Telomere expanded at apex. Volsella narrow, hook-shaped. Penisvalva not flattened at apex, expanded. Legs: Mid tibia with single pectinate spur. Hind tibia with single pectinate spur. Posterior flange of hind coxa not produced as raised lamella. Metatibial gland absent. Metabasitarsal glands absent. Hind pretarsal claws each armed with a tooth. Wings: Tegula present, broad, demiovate in shape. Vein C in fore wing present. Pterostigma narrow. Abscissa R·f3 present, running toward distal wing margin and enclosing cell with Rs·f5. Abscissae Rs·f2–3 present, connecting with Rs+M&M·f2. Cross-vein 2r-rs present, differentiated from Rs·f4 by presence of Rs·f2–3. Abscissae Rs·f4–5 differentiated into Rs·f4 and Rs·f5 by 2rs-m. Abscissa M·f2 in fore wing present, separated from Rs+M by Rs·f2. Abscissa M·f4 in fore wing present, reaching wing margin. Cross-vein 1m-cu in fore wing present. Cross-vein cu-a in fore wing present, arising from Cu and distal to, at or near M·f1. Vein Cu in fore wing present, with both branches Cu1 and Cu2. Vein A in fore wing with abscissae A·f1 and A·f2 present. Vein C in hind wing present. Vein R in hind wing present, extending past Sc+R but not reaching distal wing margin. Vein Sc+R in hind wing present. Abscissa Rs·f1 in hind wing present, shorter than 1rs-m. Abscissa Rs·f2 in hind wing present, reaching wing margin. Cross-vein 1rs-m in hind wing present, about as long as M·f1. Vein M+Cu in hind wing present. Abscissa M·f1 in hind wing present. Abscissa M·f2 in hind wing present. Cross-vein cu-a in hind wing present. Vein Cu in hind wing present. Vein A in hind wing with abscissae A·f1 and A·f2 present.

Larvae

Borowiec (2016) - Larvae of Cheliomyrmex megalonyx have been described (Wheeler 1943, Wheeler and Wheeler 1984). Presence of cocoons unknown.

References

  • 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 381, Cheliomyrmex in Dorylinae, Dorylini)
  • Ashmead, W. H. 1906. Classification of the foraging and driver ants, or Family Dorylidae, with a description of the genus Ctenopyga Ashm. Proc. Entomol. Soc. Wash. 8: 21-31 (page 27, Cheliomyrmex in Dorylinae, Dorylini)
  • Bolton, B. 1990e. Army ants reassessed: the phylogeny and classification of the doryline section (Hymenoptera, Formicidae). J. Nat. Hist. 2 24: 1339-1364 (page 1357, Cheliomyrmex in Ecitoninae, Cheliomyrmecini)
  • Bolton, B. 1994. Identification guide to the ant genera of the world. Cambridge, Mass.: Harvard University Press, 222 pp. (page 39, Cheliomyrmex in Ecitoninae, Cheliomyrmecini)
  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 143, Cheliomyrmex in Ecitoninae, Cheliomyrmecini)
  • Borgmeier, T. 1955. Die Wanderameisen der neotropischen Region. Stud. Entomol. 3: 1-720 (page 62, Revision of genus; page 58, Cheliomyrmex in Dorylinae, Cheliomyrmecini)
  • Borowiec, M.L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys. 608:1–280. doi:10.3897/zookeys.608.9427
  • 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 166, Cheliomyrmex in Ecitoninae)
  • Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 7, Cheliomyrmex in Dorylinae)
  • Dlussky, G. M.; Fedoseeva, E. B. 1988. Origin and early stages of evolution in ants. Pp. 70-144 in: Ponomarenko, A. G. (ed.) Cretaceous biocenotic crisis and insect evolution. Moskva: Nauka, 232 pp. (page 79, Cheliomyrmex in Dorylinae, Cheliomyrmecini)
  • Donisthorpe, H. 1943g. A list of the type-species of the genera and subgenera of the Formicidae. [part]. Ann. Mag. Nat. Hist. 11(10): 617-688 (page 633, Cheliomyrmex in Dorylinae, Ecitonini )
  • Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 765, Cheliomyrmex in Dorylinae, Ecitonini [Ecitonii])
  • Emery, C. 1910b. Hymenoptera. Fam. Formicidae. Subfam. Dorylinae. Genera Insectorum 102: 1-34 (page 16, Cheliomyrmex in Dorylinae, Ecitonini [Ecitini])
  • 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 365, Cheliomyrmex in Dorylinae (footnote) [Dorylidae])
  • Forel, A. 1893b. Sur la classification de la famille des Formicides, avec remarques synonymiques. Ann. Soc. Entomol. Belg. 37: 161-167 (page 163, Cheliomyrmex in Dorylinae, Dorylini)
  • Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 240, Cheliomyrmex in Dorylinae, Ecitonini )
  • Gotwald, W. H., Jr. 1971. Phylogenetic affinities of the ant genus Cheliomyrmex (Hymenoptera: Formicidae). J. N. Y. Entomol. Soc. 79: 161-173 (page 161, phylogeny)
  • Hölldobler, B.; Wilson, E. O. 1990. The ants. Cambridge, Mass.: Harvard University Press, xii + 732 pp. (page 11, Cheliomyrmex in Ecitoninae, Cheliomyrmecini)
  • Jaffe, K. 1993. El mundo de las hormigas. Baruta, Venezuela: Equinoccio (Ediciones de la Universidad Simón Bolívar), 188 pp. (page 13, Cheliomyrmex in Ecitoninae, Cheliomyrmecini)
  • Kempf, W. W. 1972b. Catálogo abreviado das formigas da regia~o Neotropical. Stud. Entomol. 15: 3-344 (page 76, Cheliomyrmex in Dorylinae, Cheliomyrmecini)
  • Mayr, G. 1870b. Neue Formiciden. Verh. K-K. Zool.-Bot. Ges. Wien 20: 939-996 (page 968, Cheliomyrmex as genus)
  • Snelling, R. R. 1981. Systematics of social Hymenoptera. Pp. 369-453 in: Hermann, H. R. (ed.) Social insects. Volume 2. New York: Academic Press, xiii + 491 pp. (page 392, Cheliomyrmex in Ecitoninae)
  • Watkins, J. F., II. 1976. The identification and distribution of New World army ants (Dorylinae: Formicidae). Waco, Texas: Baylor University Press, 102 pp. (page 6, Key to species)
  • Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 138, Cheliomyrmex in Dorylinae, Ecitonini )
  • Wheeler, W. M. 1921d. Observations on army ants in British Guiana. Proc. Am. Acad. Arts Sci. 56: 291-328 (page 319, Cheliomyrmex in Dorylinae, Cheliomyrmecini)
  • 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 635, Cheliomyrmex in Dorylinae, Ecitonini )