Anochetus

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Anochetus
Temporal range: 19–0 Ma
Early Miocene – Recent
Anochetus turneri
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Alliance: Odontomachus genus group
Genus: Anochetus
Mayr, 1861
Type species
Odontomachus ghilianii, now Anochetus ghilianii
Diversity
112 species
8 fossil species
(Species Checklist)

Anochetus turneri casent0172372 profile 1.jpg

Anochetus turneri

Anochetus turneri casent0172372 dorsal 1.jpg

Specimen Label

Synonyms

Found throughout the world's tropics and subtropics and represented by more than 100 species. The most recent revision is becoming somewhat dated (Brown 1978), along with its included key to species. Anochetus form small nests, usually with fewer than 100 workers, in soil, in termite nests, under logs and in rotten wood. A few species are arboreal. They are predacious on small invertebrates with some species known to specialise on termites, using their trap-like jaws and sting to capture and subdue prey. They commonly forage in leaf litter and are less frequently found in the open, especially when compared to workers of the closely related genus Odontomachus. Many species have been found to feign death when alarmed.

At a Glance • Trap-Jaw  
 

Photo Gallery

  • Anochetus armstrongi worker feeding during a termite nuptial flight, South Australia. Photo by Mark Newton.
  • Anochetus queen from Kerala, India. Photo by Kalesh Sadasivan.
  • A worker from Dominican Republic amber.

Identification

When viewed from the front, the outer surface of the head is complex, with narrow sections above and below bulging convexities which contain the eyes. The mandibles are long and straight, are inserted in the middle of the front margin of the head, and generally have only 2 or 3 large teeth near the tips (although they sometimes have small teeth along the inner margins which are much smaller than the teeth at the tips). The top of the head is uniformly coloured and lacks dark lines. The upper front of the head is usually smooth although it sometimes has a weak, ill-defined central groove.

The unique shape of the head and mandibles will separate these ants from all others except Odontomachus. Odontomachus and Anochetus can be easily distinguished by the characters on the back of the head. With head viewed from back near neck of pronotum, Odontomachus has dark, inverted V-shaped apophyseal lines that converge to form a distinct, sometimes shallow groove or ridge on upper back of head. In Anochetus, the V-shaped apophyseal lines are absent. In the same region of the back of head, however, nuchal carinae in Anochetus form an uninterrupted, inverted U-shaped ridge. Odontomachus and Anochetus also tend to differ in size (Anochetus are generally smaller, though there is some overlap), propodeal teeth (absent in Odontomachus but usually present in Anochetus), and petiole shape (always coniform in Odontomachus, but variable in Anochetus).

In the field, small members of Anochetus might also be mistaken for Strumigenys, from which they may be distinguished by their one-segmented waist (vs. two segments in Strumigenys).

Keys including this Genus

Keys to Species in this Genus

Distribution

Like its sister genus Odontomachus, Anochetus is widespread in the tropical and subtropical regions of the world. A few species encroach on temperate areas of South America, southern Africa, Europe (southern Spain), and Australia (reviewed in Brown, 1978).

World distribution based on political regions. View/Edit Data
Anochetus 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

Anochetus Species Richness.png

Biology

Schmidt and Shattuck (2014) - Despite their interesting mandibular structures and associated behaviors, relatively little is known about the habits of Anochetus. Brown (1976, 1978) reviewed what was known about Anochetus at the time. Torres et al. (2000) performed the most detailed study of the ecology and behavior of a single Anochetus species (Anochetus kempfi), though the applicability of these observations to other species is uncertain. The lack of information on Anochetus likely stems from the fact that its sister genus, Odontomachus, is more conspicuous and more easily studied. Anochetus are generally smaller than Odontomachus (TL 3–12 mm versus TL 6–20 mm). Colonies of Anochetus also tend to be smaller, typically containing fewer than 100 workers versus several hundred for Odontomachus (Brown, 1976, 1978), though colonies of Anochetus faurei were found to have about 400 workers (Villet et al., 1991). Anochetus also tend to nest and forage more cryptically than the epigeic Odontomachus; when they do forage above ground, Anochetus are more likely to be nocturnal than are Odontomachus (Brown, 1978). Anochetus typically nest in tight places such as in rotten twigs, under bark, or in small spaces in the soil (Wilson, 1959b; Brown, 1976, 1978; Lattke, 1986), some are apparently arboreal (Brown, 1976, 1978), and some nest in termitaries (Wheeler, 1936; Déjean et al., 1996, 1997). Anochetus often feign death when disturbed, unlike Odontomachus, which tend to attack and sting intruders (Brown, 1978).

Like Odontomachus, Anochetus use their trap-jaws to catch insect prey and can also use their mandibles to bounce themselves away from danger (Brown, 1978). The structure and neurobiology of the Anochetus trap-jaw mechanism were studied by Gronenberg & Ehmer (1996). The hunting strategy used by Anochetus tends to be more like that of some dacetines than that of Odontomachus, in that they are slower (Gronenberg & Ehmer, 1996) and more liable to ambush prey than to actively seek them out (Brown, 1978; Schatz et al., 1999). Mandibular strikes on prey are followed by a paralyzing sting (Schatz et al., 1999). The prey preferences of most Anochetus are unknown, though many appear to be specialist predators of termites (e.g., A. traegordhi; Schatz et al., 1999).

Very little is known about the social and reproductive behavior of Anochetus. Ergatoid queens are apparently common, and some species (such as members of the Anochetus inermis group; Brown, 1978) have both ergatoid and alate queens, while others may have only ergatoids (e.g., Anochetus kempfi and an unidentified species from Indonesia; Torres et al., 2000; Gobin et al., 2006). Workers of Anochetus faurei, Anochetus bequaerti, and Anochetus katonae were found to lack ovarioles, which is fairly unusual among ponerines (Villet et al., 1991). Torres et al. (2000) observed a novel behavior in A. kempfi, in which nursery workers hold unhatched eggs in their mandibles until they hatch, and never allow them to be set down on the substrate of the nest. Another interesting behavior in this species involves the execution of excess queens by the workers of a colony.

The chemical ecology of Anochetus has received little attention, though Anochetus grandidieri (Madagascar) was reported to be a source of toxic alkaloids in poison frogs (Clark et al., 2005).

Castes

Most species have winged queens, but ergatoid queens have evolved sporadically in several species (e.g. A. kempfi, Torres et al. 2000). Workers in at least 4 species lack ovaries completely (Villet et al. 1991; F. Ito pers. comm.), and this may be characteristic of the whole genus, meaning that gamergate reproduction is impossible.

Worker

Queen

Male

Morphology

Worker Morphology

 • Antennal segment count 12 • Antennal club absent • Palp formula 4,4; 4,3 • Total dental count 2-22 • Spur formula 2 (1 simple, 1 pectinate), 2 (1 simple, 1 pectinate); 2 simple, 2 (1 simple, 1 pectinate); 1 simple, 2 (1 simple, 1 pectinate); 1 simple, 1 pectinate; 0, 1 pectinate • Eyes ? • Scrobes absent • Sting present

Male Morphology

 • Antennal segment count 13 • Antennal club 0 • Palp formula 6,3; 4,4; 4,3 • Total dental count 0 • Spur formula 2 simple, 2 (1 simple, 1 pectinate)

Nomenclature

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

  • ANOCHETUS [Ponerinae: Ponerini]
    • Anochetus Mayr, 1861: 53. Type-species: Odontomachus ghilianii, by monotypy.
    • Anochetus senior synonym of Stenomyrmex: Forel, 1887: 382; Brown, 1978c: 552.
    • Anochetus senior synonym of Myrmapatetes: Brown, 1953h: 2.
  • MYRMAPATETES [junior synonym of Anochetus]
    • Myrmapatetes Wheeler, W.M. 1929b: 6. Type-species: Myrmapatetes filicornis, by original designation.
    • Myrmapatetes junior synonym of Anochetus: Brown, 1953h: 2.
  • STENOMYRMEX [junior synonym of Anochetus]
    • Stenomyrmex Mayr, 1862: 711. Type-species: Myrmecia emarginata, by subsequent designation of Wheeler, W.M. 1911f: 173.
    • Stenomyrmex subgenus of Anochetus: Dalla Torre, 1893: 47; Emery, 1911d: 110; Forel, 1917: 238; Kempf, 1964f: 237.
    • Stenomyrmex junior synonym of Anochetus: Brown, 1978c: 552.

Schmidt and Shattuck (2014):

Anochetus was erected by Mayr (1861) to house the species Odontomachus ghilianii Spinola. Like Odontomachus, Anochetus has had a stable taxonomic history at the genus level. Though Brown (1973) provisionally synonymized Anochetus under Odontomachus, he reversed himself (1976) after discovering the consistent differences in head structure between the two groups. Anochetus itself has two junior synonyms, Stenomyrmex (often treated as a subgenus of Anochetus; Mayr, 1862) and Myrmapatetes (Wheeler, 1929). Like Odontomachus, the history of family-level taxonomy for Anochetus has been complex (see discussion under Odontomachus). Schmidt's (2013) molecular phylogeny of Ponerinae confirms that Anochetus is a member of tribe Ponerini and that its sister group is Odontomachus. It is possible that Anochetus may not be mutually monophyletic with Odontomachus (see discussion under that genus), but we are retaining Anochetus as a distinct genus for now. This is consistent with the treatment by Santos et al. (2010), who could find no evidence that both are not monophyletic.

Worker

Small to medium (TL 3–12 mm; Brown, 1978) slender ants with the standard characters of Ponerini. Mandibles straight and narrow, articulating with the head medially, capable of being held open at 180°, and with a trio of apical teeth and often a row of smaller teeth along the masticatory margin. Head with a pair of long trigger setae below the mandibles. Clypeus truncate laterally and anteriorly. Frontal lobes small. Head strangely shaped: usually about as long as wide (sometimes longer than wide), with a gradual narrowing behind the eyes, the posterior margin of the head strongly concave, the nuchal carina continuously curved, and the posterior surface of the head without a pair of distinct apophyseal lines. Eyes small to moderate in size, located anterior of head midline on temporal prominences. Mesopleuron rarely divided by a transverse groove. Metanotal groove shallow to deep. Propodeum weakly to strongly narrowed dorsally, the posterior margins often with a pair of short spines or teeth. Propodeal spiracles small and round. Metatibial spur formula (1p) or (1s, 1p). Petiole variable, usually squamiform but sometimes coniform or nodiform, the posterodorsal apex often with one or two spines of variable length and acuity. Girdling constriction between pre- and postsclerites of A4 usually not apparent. Pretergite of A4 usually without a stridulitrum. Head and body shiny, striate or rugoreticulate, with sparse to abundant pilosity and little to no pubescence. Color variable, testaceous to dark brown.

Queen

Similar to worker but slightly larger, alate and with the other caste differences typical for ponerines (Brown, 1978). Ergatoid queens occur in many species; those of A. kempfi differ from conspecific workers by being smaller, with more differentiated thoracic sclerites and a larger gaster (Torres et al., 2000).

Male

See descriptions in Brown (1978) and Yoshimura & Fisher (2007).

Larva

Larvae of various Anochetus species have been described by Wheeler & Wheeler (1952, 1964, 1971a, 1976).

References

  • Arnold, G. 1915. A monograph of the Formicidae of South Africa. Part I. Ponerinae, Dorylinae. Ann. S. Afr. Mus. 14: 1-159 (page 103, Anochetus in Ponerinae, Odontomachini)
  • 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 382, Anochetus in Odontomachidae)
  • Bolton, B. 1994. Identification guide to the ant genera of the world. Cambridge, Mass.: Harvard University Press, 222 pp. (page 164, Anochetus in Ponerinae, Ponerini)
  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 159, Anochetus in Ponerinae, Ponerini)
  • Brown, W. L., Jr. 1953h. Characters and synonymies among the genera of ants. Part II. Breviora 18: 1-8 (page 2, Anochetus senior synonym of Myrmapatetes)
  • 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, Anochetus provisional junior synonym of Odontomachus)
  • Brown, W. L., Jr. 1976c. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section A. Introduction, subtribal characters. Genus Odontomachus. Stud. Entomol. 19: 67-171 (page 71, Anochetus in Ponerinae, Ponerini)
  • Brown, W. L., Jr. 1978c. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography. Stud. Entomol. 20: 549-638 PDF(page 549, Anochetus valid genus, senior synonym of Stenomyrmex and revision of genus, page 550, Anochetus in Ponerinae, Ponerini [subtribe Odontomachiti])
  • Chapman, J. W.; Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327 (page 31, Anochetus in Ponerinae, Odontomachini)
  • Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 47, Anochetus in Ponerinae)
  • 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 78, Anochetus in Ponerinae, Odontomachini)
  • 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 623, Anochetus in Ponerinae, Odontomachini)
  • Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 768, Anochetus in Ponerinae, Odontomachini)
  • Emery, C. 1911e. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 118: 1-125 (page 106, Anochetus in Ponerinae, Odontomachini)
  • Emery, C.; Forel, A. 1879. Catalogue des Formicides d'Europe. Mitt. Schweiz. Entomol. Ges. 5: 441-481 (page 455, Anochetus in Ponerinae [Poneridae])
  • Forel, A. 1887. Fourmis récoltées à Madagascar par le Dr. Conrad Keller. Mitt. Schweiz. Entomol. Ges. 7: 381-389 (page 382, Anochetus senior synonym of Stenomyrmex)
  • Forel, A. 1893b. Sur la classification de la famille des Formicides, avec remarques synonymiques. Ann. Soc. Entomol. Belg. 37: 161-167 (page 163, Anochetus in Ponerinae, Odontomachini)
  • Forel, A. 1899b. Formicidae. [part]. Biol. Cent.-Am. Hym. 3: 1-24 (page 18, Anochetus in Ponerinae, Odontomachini)
  • Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 238, Anochetus in Ponerinae, Odontomachini)
  • Gallardo, A. 1918c. Las hormigas de la República Argentina. Subfamilia Ponerinas. An. Mus. Nac. Hist. Nat. B. Aires 30: 1-112 (page 89, Anochetus in Ponerinae, Odontomachini)
  • Hölldobler, B.; Wilson, E. O. 1990. The ants. Cambridge, Mass.: Harvard University Press, xii + 732 pp. (page 11, Anochetus in Ponerinae, Odontomachini)
  • Jaffe, K. 1993. El mundo de las hormigas. Baruta, Venezuela: Equinoccio (Ediciones de la Universidad Simón Bolívar), 188 pp. (page 8, Anochetus in Ponerinae, Odontomachini)
  • Jones, T. H., R. C. Flournoy, J. A. Torres, R. R. Snelling, T. F. Spande, and H. M. Garraffo. 1999. 3-Methyl-4-phenylpyrrole from the Ants Anochetus kempfi and Anochetus mayri. Journal of Natural Products. 62:1343-1345. DOI:10.1021/np990245t
  • Larabee, F.J., Fisher, B.L., Schmidt, Matos-Maraví, P., Janda, M., Suarez, A.V. 2016. Molecular phylogenetics and diversification of trap-jaw ants in the genera Anochetus and Odontomachus (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 103, 143–154 (DOI: 10.1016/j.ympev.2016.07.024).
  • Mayr, G. 1861. Die europäischen Formiciden. Nach der analytischen Methode bearbeitet. Wien: C. Gerolds Sohn, 80 pp. (page 53, Anochetus as genus in Ponerinae [Poneridae])
  • Mayr, G. 1862. Myrmecologische Studien. Verh. K-K. Zool.-Bot. Ges. Wien 12: 649-776 (page 712, Anochetus in Formicidae, Odontomachidae)
  • 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 11, Anochetus in Formicidae, Odontomachidae)
  • Schmidt, C.A. & Shattuck, S.O. 2014. The higher classification of the ant subfamily Ponerinae (Hymenoptera: Formicidae), with a review of ponerine ecology and behavior. Zootaxa. 3817, 1–242 (doi:10.11646/zootaxa.3817.1.1)
  • Villet, M. H., R. M. Crewe, and F. D. Duncan. 1991. Evolutionary trends in the reproductive biology of ponerine ants (Hymenoptera: Formicidae). J. Nat. Hist. 25:1603-1610. DOI:10.1080/00222939100770991
  • Wheeler, G. C.; Wheeler, J. 1985b. A simplified conspectus of the Formicidae. Trans. Am. Entomol. Soc. 111: 255-264 (page 256, Anochetus in Ponerinae, Odontomachini)
  • Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 136, Anochetus in Ponerinae, Odontomachini)
  • 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 653, Anochetus in Ponerinae, Odontomachini)
  • Wilson, E. O. 1959c. Studies on the ant fauna of Melanesia V. The tribe Odontomachini. Bull. Mus. Comp. Zool. 120: 483-510 (page 483, Anochetus in Ponerinae, Odontomachini)