# Neoteny

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Retaining juvenile features into adulthood

"Paedogenesis" redirects here. For the topic of soil formation, see [Pedogenesis](/source/Pedogenesis).

**Neoteny** ([/niˈɒtəni/](https://en.wikipedia.org/wiki/Help:IPA/English)),[1][2][3][4] also called **juvenilization**,[5] is the delaying or slowing of the [physiological](/source/Physiology), or [somatic](/source/Somatic_(biology)), development of an organism, typically an animal. [Neoteny in modern humans](/source/Neoteny_in_humans) is more significant than in other primates.[6] In **progenesis** or **paedogenesis**, [sexual development](/source/Sexual_development) is accelerated.[7]

Both neoteny and progenesis result in **paedomorphism**[8] (as having the form typical of children) or **paedomorphosis**[9] (changing towards forms typical of children), a type of [heterochrony](/source/Heterochrony).[10] It is the retention in adults of traits previously seen only in the young. Such retention is important in [evolutionary biology](/source/Evolutionary_biology), [domestication](/source/Domestication), and [evolutionary developmental biology](/source/Evolutionary_developmental_biology). Some authors define paedomorphism as the retention of [larval](/source/Larval) traits, as seen in [salamanders](/source/Salamanders).[11][12][13]

## History and etymology

Diagram of the six types of shift in [heterochrony](/source/Heterochrony), a change in the timing or rate of any process in [embryonic development](/source/Embryonic_development). Predisplacement, hypermorphosis, and acceleration (red) extend development ([peramorphosis](/source/Peramorphosis)); postdisplacement, hypomorphosis, and deceleration (blue) all truncate it (paedomorphosis).

[Julius Kollmann](/source/Julius_Kollmann) created the term "neoteny" in 1885 after he described the [axolotl](/source/Axolotl)'s maturation while remaining in a [tadpole](/source/Tadpole)-like aquatic stage complete with gills, unlike other adult [amphibians](/source/Amphibians) like frogs and toads.[14][15]

The word *neoteny* is borrowed from the [German](/source/German_language) *Neotenie*, the latter constructed by Kollmann from the [Greek](/source/Greek_language) νέος (*neos*, "young") and τείνειν (*teínein*, "to stretch, to extend"). The [adjective](/source/Adjective) is either "neotenic" or "neotenous".[16] For the opposite of "neotenic", different authorities use either "gerontomorphic"[17][18] or "[peramorphic](/source/Peramorphosis)".[19] Bogin points out that Kollmann had intended the meaning to be "retaining youth", but had evidently confused the Greek *teínein* with the Latin *tenere*, which had the meaning he wanted, "to retain", so that the new word would mean "the retaining of youth (into adulthood)".[15]

In 1926, [Louis Bolk](/source/Louis_Bolk) described neoteny as the major process in humanization.[20][15] In his 1977 book *[Ontogeny and Phylogeny](/source/Ontogeny_and_Phylogeny)*,[21] [Stephen Jay Gould](/source/Stephen_Jay_Gould) noted that Bolk's account constituted an attempted justification for "scientific" racism and sexism, but acknowledged that Bolk had been right in the core idea that humans differ from other [primates](/source/Primates) in becoming sexually mature in an infantile stage of body development.[15]

## In humans

Main article: [Neoteny in humans](/source/Neoteny_in_humans)

Neoteny in humans is the slowing or delaying of body development, compared to non-human [primates](/source/Primates), resulting in features such as a large head, a flat face, and relatively short arms. These neotenic changes may have been brought about by [sexual selection in human evolution](/source/Sexual_selection_in_human_evolution). In turn, they may have permitted the development of human capacities such as emotional communication. Some evolutionary theorists have proposed that neoteny was a key feature in [human evolution](/source/Human_evolution).[22] [J. B. S. Haldane](/source/J._B._S._Haldane) states a "major evolutionary trend in human beings" is "greater prolongation of childhood and retardation of maturity."[5] [Delbert D. Thiessen](/source/Del_Thiessen) said that "neoteny becomes more apparent as early primates evolved into later forms" and that primates have been "evolving toward flat face."[23] Doug Jones argued that human evolution's trend toward neoteny may have been caused by sexual selection in human evolution for neotenous facial traits in women by men with the resulting neoteny in male faces being a "by-product" of [sexual selection](/source/Sexual_selection) for neotenous female faces.[24]

## In domestic animals

Further information: [Domestication of animals](/source/Domestication_of_animals)

Neoteny is seen in domesticated animals such as dogs and mice.[25] This is because there are more resources available, less competition for those resources, and with the lowered competition the animals expend less energy obtaining those resources. This allows them to mature and reproduce more quickly than their wild counterparts.[25] The environment that domesticated animals are raised in determines whether or not neoteny is present in those animals. Evolutionary neoteny can arise in a species when those conditions occur, and a species becomes sexually mature ahead of its "normal development". Another explanation for the neoteny in domesticated animals can be the selection for certain behavioral characteristics. Behavior is linked to genetics which therefore means that when a behavioral trait is selected for, a physical trait may also be selected for due to mechanisms like [linkage disequilibrium](/source/Linkage_disequilibrium). Often, juvenile behaviors are selected for in order to more easily domesticate a species; aggressiveness in certain species comes with adulthood when there is a need to compete for resources. If there is no need for competition, then there is no need for aggression. Selecting for juvenile behavioral characteristics can lead to neoteny in physical characteristics because, for example, with the reduced need for behaviors like aggression, there is no need for developed traits that would help in that area. Traits that may become neotenized due to decreased aggression may be a shorter muzzle and smaller general size among the domesticated individuals. Some common neotenous physical traits in domesticated animals (mainly rabbits, dogs, pigs, ferrets, cats, and even foxes) include floppy ears, changes in the reproductive cycle, curly tails, [piebald](/source/Piebald) coloration, fewer or shortened vertebra, large eyes, rounded forehead, large ears, and shortened muzzle.[26][27][28]

Neoteny and reduction in skull size – [grey wolf](/source/Grey_wolf) and [chihuahua](/source/Chihuahua_dog) skulls

When the role of dogs expanded from just being [working dogs](/source/Working_Group_(dogs)) to also being [companions](/source/Companion_dog), humans started [selective breeding](/source/Selective_breeding) dogs for [morphological](/source/Morphology_(biology)) neoteny, and this selective breeding for "neoteny or paedomorphism" "strengthened the human-canine bond."[29] Humans bred dogs to have more "juvenile physical traits" as adults, such as short snouts and wide-set eyes which are associated with puppies because people usually consider these traits to be more attractive. Some breeds of dogs with short snouts and broad heads such as the [Komondor](/source/Komondor), [Saint Bernard](/source/St._Bernard_(dog)) and [Maremma Sheepdog](/source/Maremma_Sheepdog) are more morphologically neotenous than other breeds of dogs.[30] [Cavalier King Charles spaniels](/source/Cavalier_King_Charles_spaniel) are an example of selection for neoteny because they exhibit large eyes, pendant-shaped ears and compact feet, giving them a morphology similar to puppies as adults.[29]

In 2004, a study that used 310 wolf skulls and over 700 dog skulls representing 100 breeds concluded that the evolution of dog skulls can generally not be described by heterochronic processes such as neoteny, although some pedomorphic dog breeds have skulls that resemble the skulls of juvenile wolves.[31] By 2011, the findings by the same researcher were simply "Dogs are not paedomorphic wolves."[32]

## In other animals

The axolotl (*Ambystoma mexicanum*) is a neotenous [salamander](/source/Salamander), often retaining gills throughout its life.

Neoteny has also been observed in many other species in the wild. It is important to note the difference between partial and full neoteny when looking at other species, to distinguish between juvenile traits which are advantageous in the short term and traits which are beneficial throughout the organism's life; this might provide insight into the cause of neoteny in a species.

Partial neoteny is the retention of the larval form beyond the usual age of maturation, with possible sexual development (progenesis) and eventual maturation into the adult form; this is seen in the frog *[Lithobates clamitans](/source/Lithobates_clamitans)*. Full neoteny is seen in *[Ambystoma mexicanum](/source/Ambystoma_mexicanum)* (the axolotl) and some populations of Tiger salamander (*[Ambystoma tigrinum](/source/Ambystoma_tigrinum)*), which remain in larval form throughout their lives.[33][34]

Neoteny is an ancient, pervasive phenomenon: in [urodeles](/source/Urodeles), many extant taxa are neotenic,[35] and both morphological [36] and [histological](/source/Histological) data suggest that the Middle [Jurassic](/source/Jurassic) taxon *[Marmorerpeton](/source/Marmorerpeton)* was neotenic.[37]

Two environments which favor neoteny are high altitudes and cool temperatures, because neotenous individuals have more fitness than individuals which metamorphose into an adult form. The energy required for metamorphosis detracts from individual fitness, and neotenous individuals can utilize available resources more easily.[38] This trend is seen in a comparison of salamander species at lower and higher altitudes; in a cool, high-altitude environment, neotenous individuals survive more and are more fecund than those which metamorphose into adult form.[38] Insects in cooler environments tend to exhibit neoteny in flight because wings have a high surface area and lose heat quickly; in those habitats, it is disadvantageous for insects to metamorphose into adults.[39]

### Amphibians

Many species of salamander, and amphibians in general, are environmentally neotenous. [Axolotl](/source/Axolotl) and [olm](/source/Olm) retain their gills and juvenile aquatic form throughout adulthood, in full neoteny. Gills are a common juvenile characteristic in amphibians which are kept after maturation; examples are the tiger salamander and rough-skinned newt, both of which retain gills into adulthood.[33]

*Lithobates clamitans* is partially neotenous, delaying maturation during the winter as fewer resources are available, and it can find resources more easily in its larval form. This encompasses both of the main causes of neoteny; the energy required to survive in the winter as a newly-formed adult is too great, so the organism exhibits neotenous characteristics until it can better survive as an adult.[33]

Many species of mole salamander are neotenous.[33] In the [northwestern salamander](/source/Northwestern_salamander) (*Ambystoma gracile*), high altitude is the environmental cause of neoteny.[40]

Neoteny occurs in all [salamander](/source/Salamander) families.[41] It seems to be a survival mechanism in environments with little iodine. In these circumstances, salamanders can reproduce and survive in the form of a smaller larval stage, which is aquatic and requires less food compared to terrestrial adults. If salamander larvae ingest a sufficient amount of iodine, they quickly begin metamorphosis and transform into bigger terrestrial adults, with higher dietary requirements, but an ability to disperse across dry land.[42]

### Arthropods

[Trilobite beetles](/source/Trilobite_beetle) (*[Platerodrilus ngi](/source/Platerodrilus_ngi)* pictured) are a genus of beetles with [larviform females](/source/Larviform_female); other [Elateroid beetles](/source/Elateroidea) may also have these

Neoteny is commonly seen in [flightless insects](/source/Flightless_insect), such as the females of the order [Strepsiptera](/source/Strepsiptera). Flightlessness in insects has evolved separately a number of times; factors which may have contributed to the separate evolution of flightlessness are high altitude, geographic isolation (islands), and low temperatures.[39] Under these environmental conditions, dispersal would be disadvantageous; heat is lost more rapidly through wings in colder climates. The females of certain insect groups become sexually mature without metamorphosis, and some do not develop wings; these are termed [larviform females](/source/Larviform_female). Flightlessness in some female insects has been linked to higher [fecundity](/source/Fecundity).[39] [Aphids](/source/Aphid) are an example of insects which may never develop wings, depending on their environment. If resources are abundant on a host plant, there is no need to grow wings and disperse. If resources become diminished, their offspring may develop wings to disperse to other host plants.[43]

In some groups, such as the insect families [Gerridae](/source/Gerridae), [Delphacidae](/source/Delphacidae) and [Carabidae](/source/Ground_beetle), energy costs result in neoteny; many species in these families have [small](/source/Brachyptery), neotenous wings or [none at all](/source/Aptery).[43] Some cricket species shed their wings in adulthood;[*[relevant?](https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles#Stay_on_topic)*][44] in the genus *[Ozopemon](https://en.wikipedia.org/w/index.php?title=Ozopemon&action=edit&redlink=1)*, males (thought to be the first example of neoteny in [beetles](/source/Beetle)) are significantly smaller than females due to [inbreeding](/source/Inbreeding).[45] In the termite *[Kalotermes flavicollis](/source/Kalotermes_flavicollis)*, neoteny is seen in molting females.[46]

Neoteny is also found in a few species of the [isopod](/source/Isopoda) family [Ischnomesidae](/source/Ischnomesidae), which live in the deep ocean.[47]

### Amniotes

Several avian species, such as the [manakins](/source/Manakin) *[Chiroxiphia linearis](/source/Long-tailed_manakin)* and *[Chiroxiphia caudata](/source/Blue_manakin)*, exhibit partial neoteny. The males of both species retain juvenile plumage into adulthood, losing it when they are fully mature.[48]

[Bonobos](/source/Bonobo) share many physical characteristics with humans, including neotenous skulls.[49] The shape of their skull does not change into adulthood (only increasing in size), due to [sexual dimorphism](/source/Sexual_dimorphism) and an evolutionary change in the timing of development.[49]

## Subcellular neoteny

Neoteny is usually used to describe animal development; however, neoteny is also seen in the cell [organelles](/source/Organelles). It was suggested that subcellular neoteny could explain why [sperm cells](/source/Sperm_cells) have atypical [centrioles](/source/Centrioles). One of the two sperm centrioles of [fruit fly](/source/Drosophilidae) exhibit the retention of "juvenile" centriole structure, which can be described as centriolar "neoteny". This neotenic, atypical centriole is known as the [Proximal Centriole-Like](/source/Proximal_Centriole-Like). Typical centrioles form via a step by step process in which a cartwheel forms, then develops to become a procentriole, and further matures into a centriole. The neotenic centriole of fruit fly resembles an early procentriole.[50]

## See also

- [Ageing](/source/Ageing)

- [Cuteness](/source/Cuteness)

- [Kawaii](/source/Kawaii)

- [Larviform female](/source/Larviform_female)

- [Moe (slang)](/source/Moe_(slang))

- [Neotenic complex syndrome](/source/Neotenic_complex_syndrome)

- [Neotenin](/source/Neotenin)

## References

1. **[^](#cite_ref-1)** ["neoteny"](https://www.dictionary.com/browse/neoteny). *[Dictionary.com Unabridged](/source/Dictionary.com)* (Online). n.d. Retrieved 21 April 2019.

1. **[^](#cite_ref-2)** ["neoteny"](https://www.ahdictionary.com/word/search.html?q=neoteny). *[The American Heritage Dictionary of the English Language](/source/The_American_Heritage_Dictionary_of_the_English_Language)* (5th ed.). HarperCollins. Retrieved 21 April 2019.

1. **[^](#cite_ref-3)** ["neoteny"](https://web.archive.org/web/20200322182027/https://www.lexico.com/en/definition/neoteny). *[Lexico](/source/Lexico) US English Dictionary*. [Oxford University Press](/source/Oxford_University_Press). Archived from [the original](http://www.lexico.com/en/definition/neoteny) on 22 March 2020.

1. **[^](#cite_ref-4)** ["neoteny"](https://www.merriam-webster.com/dictionary/neoteny). *[Merriam-Webster.com Dictionary](/source/Merriam-Webster)*. Merriam-Webster. [OCLC](/source/OCLC_(identifier)) [1032680871](https://search.worldcat.org/oclc/1032680871). Retrieved 21 April 2019.

1. ^ [***a***](#cite_ref-Montagu_5-0) [***b***](#cite_ref-Montagu_5-1) Montagu, A. (1989). Growing Young. Bergin & Garvey: CT.

1. **[^](#cite_ref-6)** Choi, Charles Q. (1 July 2009). ["Being More Infantile May Have Led to Bigger Brains"](http://www.scientificamerican.com/article/being-more-infantile/). *[Scientific American](/source/Scientific_American)*.

1. **[^](#cite_ref-7)** Volkenstein, M. V. 1994. *Physical Approaches to Biological Evolution*. Springer-Verlag: Berlin, [\[1\]](https://books.google.com/books?id=iiT7CAAAQBAJ&pg=PA87).

1. **[^](#cite_ref-8)** ["Paedomorphic"](https://en.wiktionary.org/wiki/paedomorphic). 21 January 2022.

1. **[^](#cite_ref-9)** ["Morphosis"](https://en.wiktionary.org/wiki/morphosis). 6 June 2022.

1. **[^](#cite_ref-Ridley_10-0)** Ridley, Mark (1985). [*Evolution*](http://www.blackwellpublishing.com/ridley/a-z/Neoteny.asp). Blackwell.

1. **[^](#cite_ref-11)** Whiteman, H.H. (1994). "Evolution of facultative paedomorphosis". *Quarterly Review of Biology*. **69** (2): 205–221. [doi](/source/Doi_(identifier)):[10.1086/418540](https://doi.org/10.1086%2F418540). [S2CID](/source/S2CID_(identifier)) [83500486](https://api.semanticscholar.org/CorpusID:83500486).

1. **[^](#cite_ref-Schell_12-0)** Schell, S. C. *Handbook of Trematodes of North America North of Mexico*, 1985, pg. 22

1. **[^](#cite_ref-13)** Ginetsinskaya, T.A. *Trematodes, Their Life Cycles, Biology and Evolution*. Leningrad, USSR: Nauka 1968. Translated in 1988, [\[2\]](https://books.google.com/books?id=JxZDAAAAYAAJ).

1. **[^](#cite_ref-14)** Kollmann, J. (1885). ["Das Ueberwintern von europäischen Frosch- und Tritonlarven und die Umwandlung des mexikanischen Axolotl"](https://www.biodiversitylibrary.org/item/42693#page/397/mode/1up) [The overwintering of European frog- and triton larvae and the transformation of the Mexican axolotl]. *Verhandlungen der Naturforschenden Gesellschaft in Basel (Proceedings of the Natural Science Society of Basel)* (in German). **7**: 387–398. From pp. 397–398: *"Dann drängt sich die Frage auf, ob das Latenzstadium der Eier, das einerseits bei Fischen, Vögeln and Säugethieren in so höchst überraschenden Formen vorkommt, anderseits das Latenzstadium bei den Wirbellosen ¹) nicht eine Variante derselben Eigenschaft der Organismen sei, welche ich Neotenie genannt habe, und die auf irgend einer Entwichlungsstufe in Kraft treten kann."* (Then the question arises whether on the one hand the latency stage of eggs — which occurs in such highly surprising forms in fish, birds and mammals — [and] on the other hand the latency stage in invertebrates ¹) be not a variant of the same property of the organisms, which I have called "neoteny" and which can come into force at any stage of development.)

1. ^ [***a***](#cite_ref-Bogin1999_15-0) [***b***](#cite_ref-Bogin1999_15-1) [***c***](#cite_ref-Bogin1999_15-2) [***d***](#cite_ref-Bogin1999_15-3) Bogin, Barry (1999). [*Patterns of Human Growth*](https://books.google.com/books?id=ScfPjwF3BngC&pg=PA158). Cambridge University Press. pp. 157–169. [ISBN](/source/ISBN_(identifier)) [978-0-521-56438-0](https://en.wikipedia.org/wiki/Special:BookSources/978-0-521-56438-0).

1. **[^](#cite_ref-16)** [Neoteny](http://www.thefreedictionary.com/neoteny), *The Free Dictionary*. 2011. Accessed April 30, 2011.

1. **[^](#cite_ref-Henke_17-0)** Henke, W. (2007). Handbook of paleoanthropology, Volume 1. Springer Books, NY.

1. **[^](#cite_ref-Hether_18-0)** Hetherington, R. (2010). The Climate Connection: Climate Change and Modern Human Evolution. Cambridge University Press.

1. **[^](#cite_ref-Hall_19-0)** Hall, B.K., Hallgrímsson, B. Monroe, W.S. (2008). Strickberger's evolution: the integration of genes, organisms and populations. Jones and Bartlett Publishers: Canada.

1. **[^](#cite_ref-20)** Bolk, Louis (1926). *Das Problem der Menschwerdung : Vortrag gehalten am 15. April 1926 auf der XXV. Versammlung der anatomischen Gesellschaft zu Freiburg* [*The Problem of Humanization: Lecture held on 15 April 1926 at the 25th Congress of the Anatomical Society at Freiberg*] (in German). Jena, Germany: Gustav Fischer.

1. **[^](#cite_ref-21)** Gould, Stephen Jay (1977). [*Ontogeny and Phylogeny*](https://archive.org/details/ontogenyphylogen00goul). Cambridge, Massachusetts: Belknap (Harvard University Press). [ISBN](/source/ISBN_(identifier)) [978-0-674-63940-9](https://en.wikipedia.org/wiki/Special:BookSources/978-0-674-63940-9).

1. **[^](#cite_ref-22)** Shea, Brian T. (1989). "Heterochrony in human evolution: The case for neoteny reconsidered". *American Journal of Physical Anthropology*. **32** (S10): 69–101. [doi](/source/Doi_(identifier)):[10.1002/ajpa.1330320505](https://doi.org/10.1002%2Fajpa.1330320505).

1. **[^](#cite_ref-Bitter_23-0)** Thiessen, D.D. (1997). Bittersweet destiny: the stormy evolution of human behavior. Transaction Publishers, N.J.

1. **[^](#cite_ref-DJones_24-0)** Jones, D.; et al. (1995). ["Sexual selection, physical attractiveness, and facial neoteny: Cross-cultural evidence and implications \[and comments and reply\]"](https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1601&context=fchd_facpub). *Current Anthropology*. **36** (5): 723–748. [doi](/source/Doi_(identifier)):[10.1086/204427](https://doi.org/10.1086%2F204427). [S2CID](/source/S2CID_(identifier)) [52840802](https://api.semanticscholar.org/CorpusID:52840802).

1. ^ [***a***](#cite_ref-sciencedirect.com_25-0) [***b***](#cite_ref-sciencedirect.com_25-1) Price, E. (1999). "Behavioral development in animals undergoing domestication". *Applied Animal Behaviour Science*. **65** (3): 245–271. [doi](/source/Doi_(identifier)):[10.1016/S0168-1591(99)00087-8](https://doi.org/10.1016%2FS0168-1591%2899%2900087-8).

1. **[^](#cite_ref-26)** Vonk, Jennifer; Shackelford, Todd (1 April 2022). "Neoteny". *Encyclopedia of Animal Cognition and Behavior*. Springer. pp. 4590–4592. [ISBN](/source/ISBN_(identifier)) [978-3-319-55064-0](https://en.wikipedia.org/wiki/Special:BookSources/978-3-319-55064-0).

1. **[^](#cite_ref-Bertone,_J._2006_27-0)** Bertone, J. (2006). Equine geriatric medicine and surgery. Saunders, MI.

1. **[^](#cite_ref-28)** Trut, L. N. (1999). "Early canid domestication: the farm-fox experiment". *American Scientist*. **87** (2): 160–169. [Bibcode](/source/Bibcode_(identifier)):[1999AmSci..87.....T](https://ui.adsabs.harvard.edu/abs/1999AmSci..87.....T). [doi](/source/Doi_(identifier)):[10.1511/1999.2.160](https://doi.org/10.1511%2F1999.2.160).

1. ^ [***a***](#cite_ref-McGreevy_29-0) [***b***](#cite_ref-McGreevy_29-1) McGreevy, P.D. & Nicholas, F.W. (1999). Some Practical Solutions to Welfare Problems in Dog Breeding. In Animal Welfare. 8: 329–341.

1. **[^](#cite_ref-30)** Beck, A.M. & Katcher, A.H. (1996). Between Pets and People: The Importance of Companionship. West Lafayette, Indiana: Purdue University Press. [ISBN](/source/ISBN_(identifier)) [1-55753-077-7](https://en.wikipedia.org/wiki/Special:BookSources/1-55753-077-7)

1. **[^](#cite_ref-31)** Drake, Abby Grace, "Evolution and development of the skull morphology of canids: An investigation of morphological integration and heterochrony" (January 1, 2004). Doctoral Dissertations Available from Proquest. Paper AAI3136721. [link](http://scholarworks.umass.edu/dissertations/AAI3136721)

1. **[^](#cite_ref-32)** Drake, Abby Grace (2011). "Dispelling dog dogma: An investigation of heterochrony in dogs using 3D geometric morphometric analysis of skull shape". *Evolution & Development*. **13** (2): 204–213. [doi](/source/Doi_(identifier)):[10.1111/j.1525-142X.2011.00470.x](https://doi.org/10.1111%2Fj.1525-142X.2011.00470.x). [PMID](/source/PMID_(identifier)) [21410876](https://pubmed.ncbi.nlm.nih.gov/21410876). [S2CID](/source/S2CID_(identifier)) [20893501](https://api.semanticscholar.org/CorpusID:20893501).

1. ^ [***a***](#cite_ref-Swingle,_W._1922_pp.397-421_33-0) [***b***](#cite_ref-Swingle,_W._1922_pp.397-421_33-1) [***c***](#cite_ref-Swingle,_W._1922_pp.397-421_33-2) [***d***](#cite_ref-Swingle,_W._1922_pp.397-421_33-3) Swingle, W. (1922). ["Experiments on the metamorphosis of neotenous amphibians"](https://zenodo.org/record/1426890). *Journal of Experimental Zoology*. **36** (4): 397–421. [Bibcode](/source/Bibcode_(identifier)):[1922JEZ....36..397S](https://ui.adsabs.harvard.edu/abs/1922JEZ....36..397S). [doi](/source/Doi_(identifier)):[10.1002/jez.1400360402](https://doi.org/10.1002%2Fjez.1400360402).

1. **[^](#cite_ref-34)** ["Ambystoma tigrinum"](http://amphibiaweb.org/species/3850). Amphibia Web.

1. **[^](#cite_ref-Wiens_et_al._2005_35-0)** Wiens, John J.; Bonett, Ronald M.; Chippindale, Paul T.; Anderson, Frank (Andy) (1 February 2005). ["Ontogeny Discombobulates Phylogeny: Paedomorphosis and Higher-Level Salamander Relationships"](https://doi.org/10.1080/10635150590906037). *Systematic Biology*. **54** (1): 91–110. [doi](/source/Doi_(identifier)):[10.1080/10635150590906037](https://doi.org/10.1080%2F10635150590906037). [PMID](/source/PMID_(identifier)) [15805013](https://pubmed.ncbi.nlm.nih.gov/15805013).

1. **[^](#cite_ref-Evans_et_al._1988_36-0)** Evans, Susan E.; Milner, Andrew R.; Mussett, Frances (1 January 1988). ["The earliest known Salamanders (Amphibia, Caudata):A record from the Middle Jurassic of England"](https://doi.org/10.1016/S0016-6995(88)80069-X). *Geobios*. **21** (5): 539–552. [Bibcode](/source/Bibcode_(identifier)):[1988Geobi..21..539E](https://ui.adsabs.harvard.edu/abs/1988Geobi..21..539E). [doi](/source/Doi_(identifier)):[10.1016/S0016-6995(88)80069-X](https://doi.org/10.1016%2FS0016-6995%2888%2980069-X). [ISSN](/source/ISSN_(identifier)) [0016-6995](https://search.worldcat.org/issn/0016-6995).

1. **[^](#cite_ref-de_Buffrénil_et_al._2015_37-0)** de Buffrénil, Vivian; Canoville, Aurore; Evans, Susan E.; Laurin, Michel (2 January 2015). ["Histological study of karaurids, the oldest known (stem) urodeles"](https://dx.doi.org/10.1080/08912963.2013.869800). *Historical Biology*. **27** (1): 109–114. [Bibcode](/source/Bibcode_(identifier)):[2015HBio...27..109D](https://ui.adsabs.harvard.edu/abs/2015HBio...27..109D). [doi](/source/Doi_(identifier)):[10.1080/08912963.2013.869800](https://doi.org/10.1080%2F08912963.2013.869800).

1. ^ [***a***](#cite_ref-Snyder,_R._1956_38-0) [***b***](#cite_ref-Snyder,_R._1956_38-1) Snyder, R. (1956). "Comparative Features of the Life Histories of *Ambystoma gracile* (Baird) from Populations at Low and High Altitudes". *Copeia*. **1956** (1): 41–50. [doi](/source/Doi_(identifier)):[10.2307/1439242](https://doi.org/10.2307%2F1439242). [JSTOR](/source/JSTOR_(identifier)) [1439242](https://www.jstor.org/stable/1439242).

1. ^ [***a***](#cite_ref-Barbosa,_P._1989_39-0) [***b***](#cite_ref-Barbosa,_P._1989_39-1) [***c***](#cite_ref-Barbosa,_P._1989_39-2) Barbosa, P.; et al. (1989). "Life-history traits of forest-inhabiting flightless Lepidoptera". *American Midland Naturalist*. **122** (2): 262–274. [doi](/source/Doi_(identifier)):[10.2307/2425912](https://doi.org/10.2307%2F2425912). [JSTOR](/source/JSTOR_(identifier)) [2425912](https://www.jstor.org/stable/2425912).

1. **[^](#cite_ref-40)** Eagleson, G.; McKeown, B. (1978). "Changes in thyroid activity of *Ambystoma gracile* (Baird) during different larval, transforming, and postmetamorphic phases". *Canadian Journal of Zoology*. **56** (6): 1377–1381. [Bibcode](/source/Bibcode_(identifier)):[1978CaJZ...56.1377E](https://ui.adsabs.harvard.edu/abs/1978CaJZ...56.1377E). [doi](/source/Doi_(identifier)):[10.1139/z78-190](https://doi.org/10.1139%2Fz78-190).

1. **[^](#cite_ref-41)** Kiyonaga, Robin R. ["METAMORPHOSIS VS NEOTENY (PAEDOMORPHOSIS) IN SALAMANDERS (CAUDATA)"](https://pages.uoregon.edu/titus/herp_old/neoteny.htm). *pages.uoregon.edu*. Retrieved 2026-02-22.

1. **[^](#cite_ref-42)** Venturi, S. (2004). ["Iodine and Evolution. DIMI-Marche"](https://web.archive.org/web/20170304010444/https://sites.google.com/site/iodinestudies/morosini). Archived from [the original](https://sites.google.com/site/iodinestudies/morosini) on 4 March 2017. Retrieved 25 September 2020.

1. ^ [***a***](#cite_ref-Harrison1980_43-0) [***b***](#cite_ref-Harrison1980_43-1) Harrison, R. (1980). "Dispersal polymorphisms in insects". *Annual Review of Ecology and Systematics*. **11** (1): 95–118. [Bibcode](/source/Bibcode_(identifier)):[1980AnRES..11...95H](https://ui.adsabs.harvard.edu/abs/1980AnRES..11...95H). [doi](/source/Doi_(identifier)):[10.1146/annurev.es.11.110180.000523](https://doi.org/10.1146%2Fannurev.es.11.110180.000523). [JSTOR](/source/JSTOR_(identifier)) [2096904](https://www.jstor.org/stable/2096904).

1. **[^](#cite_ref-jstor.org_44-0)** Harrison, R. (1980). "Dispersal Polymorphisms in Insects". *Annual Review of Ecology and Systematics*. **11** (1): 95–118. [Bibcode](/source/Bibcode_(identifier)):[1980AnRES..11...95H](https://ui.adsabs.harvard.edu/abs/1980AnRES..11...95H). [doi](/source/Doi_(identifier)):[10.1146/annurev.es.11.110180.000523](https://doi.org/10.1146%2Fannurev.es.11.110180.000523). [JSTOR](/source/JSTOR_(identifier)) [2096904](https://www.jstor.org/stable/2096904).

1. **[^](#cite_ref-45)** Jordal, B. H.; Beaver, R. A.; Normark, B. B.; Farrell, B. D. (2002). ["Extraordinary sex ratios and the evolution of male neoteny in sib-mating *Ozopemon* beetles"](https://doi.org/10.1046%2Fj.1095-8312.2002.00025.x). *Biological Journal of the Linnean Society*. **75** (3): 353–360. [doi](/source/Doi_(identifier)):[10.1046/j.1095-8312.2002.00025.x](https://doi.org/10.1046%2Fj.1095-8312.2002.00025.x).

1. **[^](#cite_ref-dx.doi.org_46-0)** Soltani-Mazouni, N.; Bordereau, C. (1987). "Changes in the cuticle, ovaries and colleterial glands during the pseudergate and neotenic molt in *Kalotermes flavicollis* (FABR.) (Isoptera : Kalotermitidae)". *International Journal of Insect Morphology and Embryology*. **16** (3–4): 221–225. [doi](/source/Doi_(identifier)):[10.1016/0020-7322(87)90022-5](https://doi.org/10.1016%2F0020-7322%2887%2990022-5).

1. **[^](#cite_ref-47)** Brokeland, W.; Brandt, A. (2004). "Two new species of Ischnomesidae (Crustacea: Isopoda) from the Southern Ocean displaying neoteny". *Deep-Sea Research Part II*. **51** (14–16): 1769–1785. [Bibcode](/source/Bibcode_(identifier)):[2004DSRII..51.1769B](https://ui.adsabs.harvard.edu/abs/2004DSRII..51.1769B). [doi](/source/Doi_(identifier)):[10.1016/j.dsr2.2004.06.034](https://doi.org/10.1016%2Fj.dsr2.2004.06.034).

1. **[^](#cite_ref-48)** Foster, M. (1987). ["Delayed maturation, neoteny, and social system differences in two manakins of genus *Chiroxyphia*"](https://zenodo.org/record/1235115). *Evolution*. **41** (3): 547–558. [doi](/source/Doi_(identifier)):[10.2307/2409256](https://doi.org/10.2307%2F2409256). [JSTOR](/source/JSTOR_(identifier)) [2409256](https://www.jstor.org/stable/2409256). [PMID](/source/PMID_(identifier)) [28563802](https://pubmed.ncbi.nlm.nih.gov/28563802).

1. ^ [***a***](#cite_ref-ReferenceA_49-0) [***b***](#cite_ref-ReferenceA_49-1) Shea, B. T. (1983). "Paedomorphosis and Neoteny in the Pygmy Chimpanzee". *Science*. **222** (4623): 521–522. [Bibcode](/source/Bibcode_(identifier)):[1983Sci...222..521S](https://ui.adsabs.harvard.edu/abs/1983Sci...222..521S). [doi](/source/Doi_(identifier)):[10.1126/science.6623093](https://doi.org/10.1126%2Fscience.6623093). [JSTOR](/source/JSTOR_(identifier)) [1691380](https://www.jstor.org/stable/1691380). [PMID](/source/PMID_(identifier)) [6623093](https://pubmed.ncbi.nlm.nih.gov/6623093).

1. **[^](#cite_ref-50)** Avidor-Reiss, Tomer; Turner, Katerina (2019), Kloc, Malgorzata (ed.), ["The Evolution of Centriole Structure: Heterochrony, Neoteny, and Hypermorphosis"](https://doi.org/10.1007/978-3-030-23173-6_1), *The Golgi Apparatus and Centriole: Functions, Interactions and Role in Disease*, Results and Problems in Cell Differentiation, vol. 67, Cham: Springer International, pp. 3–15, [doi](/source/Doi_(identifier)):[10.1007/978-3-030-23173-6_1](https://doi.org/10.1007%2F978-3-030-23173-6_1), [ISBN](/source/ISBN_(identifier)) [978-3-030-23173-6](https://en.wikipedia.org/wiki/Special:BookSources/978-3-030-23173-6), [PMC](/source/PMC_(identifier)) [7576685](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7576685), [PMID](/source/PMID_(identifier)) [31435789](https://pubmed.ncbi.nlm.nih.gov/31435789), retrieved 12 October 2023{{[citation](https://en.wikipedia.org/wiki/Template:Citation)}}: CS1 maint: work parameter with ISBN ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN))

## Further reading

- Bergstorm, Carl T. & Dugatkin, Lee Alan (2012). *Evolution*, W.W. Norton [ISBN](/source/ISBN_(identifier)) [039391349X](https://en.wikipedia.org/wiki/Special:BookSources/039391349X)

v t e The development of phenotype Key concepts Genotype–phenotype distinction Reaction norm Gene–environment interaction Gene–environment correlation Operon Heritability Quantitative genetics Heterochrony Neoteny Heterotopy Genetic architecture Canalisation Genetic assimilation Dominance Epistasis Fitness landscape/evolutionary landscape Pleiotropy Plasticity Polygenic inheritance Transgressive segregation Sequence space Non-genetic influences Epigenetics Maternal effect Genomic imprinting Dual inheritance theory Polyphenism Developmental architecture Developmental biology Morphogenesis Eyespot Pattern formation Segmentation Metamerism Modularity Evolution of genetic systems Evolvability Robustness Neutral networks Evolution of sexual reproduction Tinkering Control of development Systems Regulation of gene expression Gene regulatory network Evo-devo gene toolkit Evolutionary developmental biology Homeobox Hedgehog signaling pathway Notch signaling pathway Elements Homeotic gene Hox gene Pax genes eyeless gene Distal-less Engrailed cis-regulatory element Ligand Morphogen Cell surface receptor Transcription factor Influential figures C. H. Waddington Richard Lewontin François Jacob + Jacques Monod Lac operon Eric F. Wieschaus Christiane Nüsslein-Volhard William McGinnis Mike Levine Sean B. Carroll Endless Forms Most Beautiful Debates Nature versus nurture Morphogenetic field Index of evolutionary biology articles

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Adapted from the Wikipedia article [Neoteny](https://en.wikipedia.org/wiki/Neoteny) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Neoteny?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.