Editing Tadpole (section)

=== Anura ===
[[File:Tadpoles 10 days.jpg|thumb|Ten-day-old tadpoles. The external gills will eventually be hidden by a layer of skin.|alt=|upright=0.8]]
Tadpoles of frogs and toads are usually globular, with a laterally compressed tail with which they swim by [[lateral undulation]]. When first hatched, anuran tadpoles have external gills that are eventually covered by skin, forming an [[Operculum (fish)|opercular chamber]] with internal gills vented by [[Spiracle (vertebrates)|spiracles]]. Depending on the species, there can be two spiracles on both sides of the body, a single spiracle on the underside near the vent, or a single spiracle on the left side of the body.<ref>{{Cite web|url=https://www.pwrc.usgs.gov/tadpole/tadspir.htm|title=North American Tadpoles Spiracle|url-status=live|archive-url=https://web.archive.org/web/20161228004400/https://www.pwrc.usgs.gov/tadpole/tadspir.htm|archive-date=28 December 2016|access-date=12 April 2020}}</ref> Newly hatched tadpoles are also equipped with a cement gland which allows them to attach to objects. The tadpoles have a cartilaginous skeleton and a [[notochord]] which eventually develops into a proper spinal cord.
[[Image:Bufo metamorphosis.jpg|thumb|444x444px|Metamorphosis of ''[[Bufo bufo]]''|alt=|left]]
Anuran tadpoles are usually herbivorous, feeding on soft decaying plant matter. The gut of most tadpoles is long and spiral-shaped to efficiently digest organic matter and can be seen through the bellies of many species. Though many tadpoles will feed on dead animals if available to them, only a few species of frog have strictly carnivorous tadpoles, an example being the frogs of the family [[Ceratophryidae]], their cannibalistic tadpoles having wide gaping mouths with which they devour other organisms, including other tadpoles. Another example is the tadpoles of the New Mexico spadefoot toad (''[[New Mexico spadefoot toad|Spea multiplicata]]'') which will develop a carnivorous diet along with a broader head, larger jaw muscles, and a shorter gut if food is scarce, allowing them to consume fairy shrimp and their smaller herbivorous siblings.<ref>{{Cite journal|last=Pfennig|first=David|date=1990|title=The adaptive significance of an environmentally-cued developmental switch in an anuran tadpole|journal=Oecologia|volume=85|issue=1|pages=101–107|doi=10.1007/BF00317349|pmid=28310961|bibcode=1990Oecol..85..101P|s2cid=20616439}}</ref> A few genera such as [[Pipidae]] and [[Microhylidae]] have species whose tadpoles are [[filter feeder]]s that swim through the water column feeding on [[plankton]]. [[Megophrys]] tadpoles feed at the water surface using unusual funnel-shaped mouths.<ref>{{Cite web|url=https://animaldiversity.org/accounts/Megophryidae/|title=Megophryidae|website=[[Animal Diversity Web]] }}</ref>

[[File:Anatomy WoodFrog.png|alt=Anatomy of a Wood frog tadpole|thumb|Anatomy of a wood frog tadpole ([[Wood frog|Lithobates sylvaticus]])]]
As a frog tadpole matures it gradually develops its limbs, with the back legs growing first and the front legs second. The tail is absorbed into the body using [[apoptosis]]. Lungs develop around the time as the legs start growing, and tadpoles at this stage will often swim to the surface and gulp air. During the final stages of metamorphosis, the tadpole's mouth changes from a small, enclosed mouth at the front of the head to a large mouth the same width as the head. The intestines shorten as they transition from a herbivorous diet to the carnivorous diet of adult frogs.

Tadpoles vary greatly in size, both during their development and between species. For example, in a single family, [[Megophryidae]], length of late-stage tadpoles varies between {{convert|3.3|cm}} and {{convert|10.6|cm}}.<ref name="Li">{{cite journal|last=Li|first=Cheng |author2=Guo, Xian-Guang |author3=Wang, Yue-Zhao|year=2011|title=Tadpole types of Chinese megophryid frogs (Anura: Megophryidae) and implications for larval evolution|journal=Current Zoology|volume=57|issue=1|pages=93–100|doi=10.1093/czoolo/57.1.93 |doi-access=free}}</ref> The tadpoles of the paradoxical frog (''[[Pseudis paradoxa]])'' can reach up to {{convert|27|cm}},<ref name="Bokermann1967">{{cite journal| author=Bokermann, W.C.A. | year=1967 | title=Girinos de anfíbios brasileiros—3: sôbre um girino gigante de Pseudis paradoxa (Amphibia, Pseudidae) | journal=Revista Brasileira de Biologia | volume=27 | pages=209–212 }}</ref> the longest of any frog,<ref>{{cite journal|author=Crump, Martha L.|year=2009|title=Amphibian diversity and life history|journal=Amphibian Ecology and Conservation. A Handbook of Techniques|pages=3–19|doi=10.1093/oso/9780199541188.003.0001 |isbn=978-0-19-954118-8 |url=http://fds.oup.com/www.oup.com/pdf/13/9780199541188_chapter1.pdf|url-status=dead|archive-url=https://web.archive.org/web/20110715022035/http://fds.oup.com/www.oup.com/pdf/13/9780199541188_chapter1.pdf|archive-date=2011-07-15}}</ref> before shrinking to a mere snout-to-vent length of {{convert|3.4|–|7.6|cm|in|abbr=on}}.

While most anuran tadpoles inhabit [[wetland]]s, [[pond]]s, [[vernal pool]]s, and other small bodies of water with slow moving water, a few species are adapted to different environments. Some frogs have terrestrial tadpoles, such as the family [[Ranixalidae]], whose tadpoles are found in wet crevices near streams. The tadpoles of ''[[Micrixalus herrei]]'' are adapted to a [[fossorial]] lifestyle, with a muscular body and tail, eyes covered by a layer of skin, and reduced pigment.<ref>{{Cite journal|date=30 March 2016|title=Unearthing the Fossorial Tadpoles of the Indian Dancing Frog Family Micrixalidae|journal=PLOS ONE|volume=11|pages=e0151781|doi=10.1371/journal.pone.0151781|last1=Senevirathne|first1=Gayani|last2=Garg|first2=Sonali|last3=Kerney|first3=Ryan|last4=Meegaskumbura|first4=Madhava|last5=Biju|first5=S. D.|issue=3|pmid=27027870|pmc=4814069|bibcode=2016PLoSO..1151781S|doi-access=free}}</ref> Several frogs have stream dwelling tadpoles equipped with a strong [[Sucker (zoology)|oral sucker]] that allows them to hold onto rocks in fast flowing water, two examples being the Indian purple frog (''[[Purple frog|Nasikabatrachus sahyadrensis]]'') and the tailed frogs ([[Tailed frog|Ascaphus]]) of Western North America. Although there are no marine tadpoles, the tadpoles of the [[crab-eating frog]] can cope with brackish water.<ref>{{Cite web|url=https://www.ecologyasia.com/verts/amphibians/crab-eating_frog.htm|title=Crab-eating frog}}</ref>

Some anurans will provide parental care towards their tadpoles. Frogs of the genus [[Afrixalus]] will lay their eggs on leaves above water, folding the leaves around the eggs for protection. Female [[Pipa (frog)|Pipa]] frogs will embed the eggs into their backs where they get covered by a thin layer of skin. The eggs will hatch underneath her skin and grow, eventually leaving as either large tadpoles (such as in ''[[Sabana Surinam toad|Pipa parva]]'') or as fully formed froglets (''[[Common Surinam toad|Pipa pipa]]''). Female marsupial frogs ([[Hemiphractidae]]) will carry eggs on her back for various amounts of time, with it going as far as letting the tadpoles develop into tiny froglets in a pouch. Male African bullfrogs (''[[African bullfrog|Pyxicephalus adspersus]]'') will keep watch over their tadpoles, attacking anything that might be a potential threat, even though he may eat some of the tadpoles himself.<ref>{{Cite journal |last1=Cook |first1=C. L. |last2=Ferguson |first2=J. W. H. |last3=Telford |first3=S. R. |date=June 2001 |title=Adaptive Male Parental Care in the Giant Bullfrog, Pyxicephalus adspersus |journal=Journal of Herpetology |volume=35 |issue=2 |pages=310–315 |doi=10.2307/1566122 |jstor=1566122}}</ref>

Males of the Emei mustache toads (''[[Leptobrachium boringii]]'') will construct nests along riverbanks where they breed with females and keep watch over the eggs, losing as much as 7.3% of their body mass in the time they spend protecting the nest.<ref>{{Cite journal |last1=Zheng |first1=Yuchi |last2=Deng |first2=Duncan |last3=Li |first3=Shuqiang |last4=Fu |first4=Jinzhong |date=April 2010 |title=Aspects of the breeding biology of the Omei mustache toad (Leptobrachium boringii): Polygamy and paternal care |url=https://www.researchgate.net/publication/233516351 |journal=Amphibia-Reptilia |volume=31 |issue=2 |pages=183–194 |doi=10.1163/156853810791069092 |via=ResearchGate|doi-access=free }}</ref> Male midwife toads (''[[Midwife toad|Alytes]]'') will carry eggs between their legs to protect them from predators, eventually releasing them into a body of water when they are ready to hatch. Poison dart frogs ([[Poison dart frog|Dendrobatidae]]) will carry their tadpoles to various locations, usually [[phytotelma]], where they remain until metamorphosis. Some female dart frogs such as the strawberry poison dart frog (''[[Strawberry poison-dart frog|Oophaga pumilio]]'') will regularly lay unfertilized eggs for the developing tadpoles to feed on.<ref>{{Cite journal|last=Brandt, Pröhl|first=Annely, Heike|date=April 2002|title=Female activity patterns and aggressiveness in the strawberry poison frog Dendrobates pumilio (Anura: Dendrobatidae)|url=https://www.researchgate.net/publication/233513296|journal=Amphibia-Reptilia|volume=23|issue=2|pages=129–140|doi=10.1163/156853802760061778|via=ResearchGate|doi-access=free}}</ref>