Temporal range: 20.43–0 Ma Miocene – Recent
|Formica atrata, now Cephalotes atratus|
16 fossil species
|Based on Ward et al. (2014), Blaimer et al. (2018) and Li et al. (2018).|
Common in the New World tropics, Turtle ants have long attracted the attention of tropical biologists due to their unusual soldier caste with large armored heads that match the size and shape of their nest entrances. Nests occupy pre-existing arboreal cavities, and soldiers function as living doors to admit incoming foragers or exclude potential intruders.
Cephalotes (119 species) consume a mostly herbivorous diet supplemented by pollen, bird feces and vertebrate urine (e.g. Cephalotes atratus) (Baroni Urbani and de Andrade 1997; Powell 2008).
Keys including this Genus
Keys to Species in this Genus
Distribution and Richness based on AntMaps
The biology of many Cephalotes species is not known. Ants in this genus are common in the New World tropics and subtropics and are especially abundant and diverse in the canopies of Neotropical forests. The majority of species are arboreal. Species that live in other strata inhabit smaller trees, bushes or grass stems. These noon-arboreal species, due to their accessibility, are among the better studied members of the genus. There are also species that can be found in downed wood but it is likely the wood housed the colony before it fell to the ground. Soil nests are not known for any species nor do most species appear to extensively excavate plant tissue. They nest instead in preformed cavities. Overall, ants in the genus utilize a wide range of plants. Some species are predictable in their plant use but none appear to have evolved specialized mutualisms with particular plant species.
Worker castes typically include two forms, a worker and soldier, but there are a few species that are monomorphic. The larger soldier caste typically has an enlarged head disk. In some species the head of the soldier is very different from the worker while in others these differences are less pronounced. Queens and soldiers tend to share similar head morphology. Soldiers use their heads to plug the nest entrance. This can be very effective in excluding potential intruders. Other morphological differences between the worker castes are present but these differences have not been studied as well as head moprhology.
The behavioral repertoire of Cephalotes varians has been examined in great detail (ethograms from Wilson 1976, Cole 1980 and Cole 1983). Soldiers do little else besides defend the nest. This specialized soldier behavior is presumed to be the norm for most species. An especially interesting behavior occurs when workers are dislodged from trees: they "fly" towards the tree, often grabbing the trunk well above the ground (video).
Mature nest size varies, by species, from less than a hundred to many thousands of workers. Available evidence suggests most species are monogynous. Queens may mate with multiple males.
The proventriculus of the Cephalotes is peculiar relative to other ants. The morphology of the structure suggests it serves as a powerful pump and filter. This does not appear to lead these ants to have a highly specialized diet as most species appear to be general scavengers. Foragers have been observed feeding on carrion, bird feces, extrafloral nectaries and even tending membracids. Pollen feeding has been observed in some species, and this is somewhat specialized for ants, but it is not evident that any species restricts its diet to this resource in any significant way. Evidence for pollen feeding in Cephalotes has accumulated, in part, via finding digested pollen grains seen in infrabucal pellets. It has been suggested that the morphology of the proventriculus is a specialization for processing pollen.
More research examining all aspects of the biology of Cephalotes is needed. Our present understanding of these ants is largely based on species that live in locations other than the forest canopy, which is where Cephalotes are most common and diverse.
Powell (2016) studied how nesting ecology in Cephalotes has shaped the diversification of an elaborate soldier caste. The evolution of morphologically specialized soldier heads was associated with substantial shifts in nest-entrance preferences, and in many species there is a match between head sizes and entrance sizes. These findings suggest the general hypothesis that the evolution of novel caste types is driven by major shifts in ecological specialization, while the size distribution of existing castes tracks minor shifts in resource use.
All Records for Genus
|Cephalotes pusillus||22||44||28M+16A||Brazil||Cristiano et al., 2017|
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- CEPHALOTES [Myrmicinae: Cephalotini]
- Cephalotes Latreille, 1802a: 357. Type-species: Formica atrata, by monotypy.
- [Type-species not Formica cephalotes, unjustified subsequent designation by Wheeler, W.M. 1911f: 160; corrected by Wheeler, W.M. 1913a: 78.]
- Cephalotes junior synonym of Cryptocerus: Fabricius, 1804: 419.
- Cephalotes senior synonym of Cryptocerus: Wheeler, W.M. 1913a: 78; Smith, M.R. 1949c: 19; Kempf, 1951: 107.
- Cephalotes senior synonym of Eucryptocerus, †Exocryptocerus, Zacryptocerus (and its junior synonyms Cyathocephalus, Cyathomyrmex, Harnedia, Hypocryptocerus, Paracryptocerus): De Andrade & Baroni Urbani, 1999: 59.
- CRYPTOCERUS [junior synonym of Cephalotes]
- Cryptocerus Latreille, 1803: 311. Type-species: Formica atrata, by subsequent designation of Latreille, 1810: 437.
- [Type-species not Cryptocerus umbraculatus, unjustified subsequent designation by Emery, 1914c: 38; repeated in Emery, 1924d: 305.]
- Cryptocerus junior synonym of Cephalotes: Wheeler, W.M. 1913a: 78; Smith, M.R. 1949c: 19; see also discussion in Kempf, 1951: 105. [Cephalotes and Cryptocerus share the same type-species, synonymy is therefore absolute.]
- CYATHOMYRMEX [junior synonym of Cephalotes]
- Cyathomyrmex Creighton, 1933: 100 [as subgenus of Cryptocerus]. Replacement name for Cyathocephalus Emery, above. [Junior homonym of Cyathocephalus Kessler, 1868: 135 (Cestoda).]
- Cyathomyrmex subgenus of Paracryptocerus: Smith, M.R. 1949c: 21.
- Cyathomyrmex junior synonym of Paracryptocerus: Kempf, 1972a: 175.
- Cyathomyrmex junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- EUCRYPTOCERUS [junior synonym of Cephalotes]
- Eucryptocerus Kempf, 1951: 127. Type-species: Cryptocerus oculatus, by original designation.
- Eucryptocerus junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- †EXOCRYPTOCERUS [junior synonym of Cephalotes]
- †Exocryptocerus Vierbergen & Scheven, 1995: 159. Type-species: †Exocryptocerus serratus, by original designation.
- †Exocryptocerus junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- HARNEDIA [junior synonym of Cephalotes]
- Harnedia Smith, M.R. 1949c: 20 [as subgenus of Paracryptocerus]. Type-species: Cryptocerus umbraculatus, by original designation.
- Harnedia junior synonym of Paracryptocerus: Kempf, 1972a: 175.
- Harnedia junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- HYPOCRYPTOCERUS [junior synonym of Cephalotes]
- Hypocryptocerus Wheeler, W.M. 1920: 53 [as subgenus of Cryptocerus]. Type-species: Formica haemorrhoidalis, by original designation.
- Hypocryptocerus raised to genus: Wheeler, W.M. 1936b: 200.
- Hypocryptocerus junior synonym of Zacryptocerus: Kempf, 1973c: 460.
- Hypocryptocerus junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- PARACRYPTOCERUS [junior synonym of Cephalotes]
- Paracryptocerus Emery, 1915i: 192 [as subgenus of Cryptocerus]. Type-species: Cryptocerus spinosus, by original designation.
- Paracryptocerus raised to genus: Smith, M.R. 1949c: 20; Kempf, 1951: 153.
- Paracryptocerus senior synonym of Cyathocephalus (homonym), Cyathomyrmex, Harnedia: Kempf, 1972a: 175.
- Paracryptocerus junior synonym of Zacryptocerus: Kempf, 1973c: 460.
- Paracryptocerus junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- ZACRYPTOCERUS [junior synonym of Cephalotes]
- Zacryptocerus Wheeler, W.M. 1911f: 175 (see also footnote). Type-species: Cryptocerus clypeatus, by original designation.
- [Zacryptocerus Ashmead, 1905b: 384. Nomen nudum. (Based on a non-existent type-species: Cryptocerus multistrigus. Nomen nudum, attributed to Smith, F.).]
- Zacryptocerus senior synonym of Hypocryptocerus, Paracryptocerus (and its junior synonyms Cyathomyrmex, Cyathocephalus (homonym), Harnedia): Kempf, 1973c: 460.
- Zacryptocerus junior synonym of Cephalotes: De Andrade & Baroni Urbani, 1999: 59.
- Baroni Urbani, C.; de Andrade, M. L. 1999. [Untitled. Cephalotes bloosi Baroni Urbani & de Andrade new species.] Pp. 549-551 in: De Andrade, M. L., Baroni Urbani, C. Diversity and adaptation in the ant genus Cephalotes, past and present. Stuttg. Beitr. (page 59, Cephalotes senior synonym of Eucryptocerus, *Exocryptocerus, Zacryptocerus (and its junior synonyms Cyathocephalus, Cyathomyrmex, Harnedia, Hypocryptocerus, Paracryptocerus))
- Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 194, Cephalotes in Myrmicinae, Cephalotini [Type-species not Formica cephalotes, unjustified subsequent designation by Wheeler, W.M. 1911:160; corrected by Wheeler, W.M. 1913:78.])
- Baroni Urbani C., de Andrade M.L. 1997. Pollen Eating, Storing, and Spitting by Ants. Naturwissenschaften 84: 256–258. PDF
- 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, Cephalotes in Myrmicinae, Cryptocerini (anachronism))
- Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 42, Cephalotes in Myrmicinae, Cryptocerini)
- Emery, C. 1924f . Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 303, Cephalotes in Myrmicinae, Cryptocerini)
- Fabricius, J. C. 1804. Systema Piezatorum secundum ordines, genera, species, adjectis synonymis, locis, observationibus, descriptionibus. Brunswick: C. Reichard, xiv + 15-439 + 30 pp. (page 419, Cephalotes as junior synonym of Cryptocerus)
- Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 246, Cephalotes in Myrmicinae, Cryptocerini)
- Hespenheide, H.A. 1986. Mimicry of ants of the genus Zacryptocerus (Hymenoptera: Formicidae). Journal of the New York Entomological Society 94: 394-408.
- Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 105, Cephalotes in Myrmicinae, Cephalotini)
- Latreille, P. A. 1802b. Histoire naturelle générale et particulière des Crustacés et des insectes. Tome 3. Familles naturelles des genres. Paris: F. Dufart, xii + 467 pp. (page 357, Cephalotes as genus)
- Powell, S. 2008. Ecological specialization and the evolution of a specialized caste in Cephalotes ants. Functional Ecology, 22: 902–911.
- Powell, S. 2016. A comparative perspective on the ecology of morphological diversification in complex societies: nesting ecology and soldier evolution in the turtle ants. Behavioral Ecology and Sociobiology, 70: 1075–1085.
- Smith, M. R. 1949c. On the status of Cryptocerus Latreille and Cephalotes Latreille (Hymenoptera: Formicidae). Psyche (Camb.) 56: 18-21 (page 19, Cephalotes in Myrmicinae, Cephalotini; Cephalotes senior synonym of Cryptocerus)
- Wheeler, W. M. 1913a. Corrections and additions to "List of type species of the genera and subgenera of Formicidae". Ann. N. Y. Acad. Sci. 23: 77-83 (page 78, Cephalotes senior synonym of Cryptocerus)
- 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 665, Cephalotes in Myrmicinae, Cryptocerini)