Newt

<h2 id="etymology">Etymology</h2>

The <a href="/facts/Old_English/9rsmQG2a">Old English</a> name of the animal was efte, efeta (of unknown origin), resulting in <a href="/facts/Middle_English/dj1wHvwd">Middle English</a> eft;
this word was transformed irregularly into euft, evete, or ewt(e). The initial "n" was added from the indefinite article "an" by <a href="/facts/English_articles/CTs9Lg2I">provection (juncture loss)</a> ("an eft" → "a n'eft" → ...) by the early 15th century.<a class="footnote-ref" id="fnref:1" href="#fn:1">1</a> The form "newt" appears to have arisen as a dialectal variant of eft in <a href="/facts/Staffordshire/w4KJHAXz">Staffordshire</a>, but entered Standard English by the Early Modern period (used by Shakespeare in <a href="/facts/Macbeth/E8K4sYoC">Macbeth</a> iv.1).<a class="footnote-ref" id="fnref:2" href="#fn:2">2</a> The regular form eft, now only used for newly metamorphosed specimens, survived alongside newt, especially in composition, the larva being called "water-eft" and the mature form "land-eft" well into the 18th century, but the simplex "eft" as equivalent to "water-eft" has been in use since at least the 17th century.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a>
Dialectal English and Scots also has the word ask (also awsk, esk in Scots<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a>) used for both newts and <a href="/facts/Lacertidae/ICYrQcAa">wall lizards</a>, from Old English āþexe, from <a href="/facts/Proto-Germanic/LJrKRx5A">Proto-Germanic</a> *agiþahsijǭ, literally "lizard-badger" or "distaff-like lizard" (compare German Eidechse and Echse, both "lizard;" *agi- is ultimately cognate with Greek ὄφις "snake," from <a href="/facts/Proto-Indo-European_language/cVLNoM3p">Proto-Indo-European</a> *h₁ogʷʰis<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a>). Latin had the name stellio for a type of spotted newt, now used for species of the genus <a href="/facts/Stellagama/FGG7frUx">Stellagama</a>. Ancient Greek had the name κορδύλος, presumably for the water newt (immature newt, eft).<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> German has Molch, from <a href="/facts/Middle_High_German/LI9JRDIu">Middle High German</a> mol, wikt:olm, like the English term of unknown etymology.
Newts are also known as Tritones (viz., named for the mythological <a href="/facts/Triton_(mythology)/DhS8o3WY">Triton</a>) in historical literature, and "triton" remains in use as common name in some Romance languages, such as Spanish and Romanian, but as well as in Greek, Russian, and Bulgarian. The systematic name Tritones was introduced alongside Pleurodelinae by <a href="/facts/Johann_Jakob_von_Tschudi/9Ez1x3Ju">Tschudi</a> in 1838, based on the type genus named Triton by <a href="/facts/Josephus_Nicolaus_Laurenti/AgfkksJn">Laurenti</a> in 1768. Laurenti's Triton was renamed to <a href="/facts/Triturus/HqC4zn3R">Triturus</a> ("Triton-tail") by <a href="/facts/Constantine_Samuel_Rafinesque/d7XBK7x5">Rafinesque</a> in 1815.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> Tschudi's Pleurodelinae is based on the type genus <a href="/facts/Pleurodeles/AIVfw2jd">Pleurodeles</a> (ribbed newt) named by <a href="/facts/Karl_Michahelles/ErIGy3V1">Michahelles</a> in 1830 (the name meaning "having prominent ribs," formed from πλευρά "ribs" and δῆλος "conspicuous").
Collective nouns for newts are flotilla and armada.

<h2 id="distribution-and-habitats">Distribution and habitats</h2>

Newts are found in North America, Europe, North Africa and Asia. The <a href="/facts/Taricha/XhUdTUhd">Pacific newts</a> (Taricha) and the <a href="/facts/Notophthalmus/sgjs9CDE">Eastern newts</a> (Notophthalmus) with together seven species are the only representatives in North America, while most diversity is found in the Old World: In Europe and the Middle East, the group's likely origin, eight genera with roughly 30 species are found, with the <a href="/facts/Pleurodeles/AIVfw2jd">ribbed newts</a> (Pleurodeles) extending to northernmost Africa. Eastern Asia, from Eastern India over Indochina to Japan, is home to five genera with more than 40 species.
Newts are <a href="/facts/Semiaquatic/6JHes4oC">semiaquatic</a>, spending part of the year in the water for reproduction and the rest of the year on land. While most species prefer stagnant water bodies such as ponds, ditches, or flooded meadows for reproduction, some species such as the <a href="/facts/Danube_crested_newt/maDJ2ysJ">Danube crested newt</a> can also occur in slow-flowing rivers. The <a href="/facts/Calotriton/3sqv0Jps">European brook newts</a> (Calotriton) and <a href="/facts/Euproctus/lhtFTnKf">European mountain newts</a> (Euproctus) have even adapted to life in cold, oxygen-rich mountain streams. During their terrestrial phase, newts live in humid habitats with abundant cover such as logs, rocks, or earth holes.

<h2 id="characteristics">Characteristics</h2>
Newts share many of the characteristics of their salamander kin, <a href="/facts/Caudata/pCeXrHka">Caudata</a>, including semipermeable glandular skin, four equal-sized limbs, and a distinct tail. The newt's skin, however, is not as smooth as that of other salamanders.<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> The <a href="/facts/Cell_(biology)/bLM9UQvy">cells</a> at the site of an injury have the ability to un<a href="/facts/Cellular_differentiation/bCVqUG7w">differentiate</a>, reproduce rapidly, and differentiate again to create a new limb or organ. One hypothesis is that the undifferentiated cells are related to <a href="/facts/Tumor/K0ytzmPz">tumor</a> cells, since chemicals that produce tumors in other animals will produce additional limbs in newts.<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>

<h2 id="development">Development</h2>
The main breeding season for newts (in the Northern Hemisphere) is in June and July. A single newt female can produce hundreds of eggs. For instance, the warty newt can produce 200–300 eggs (Bradford 2017). After courtship rituals of varying complexity, which take place in ponds or slow-moving streams, the male newt transfers a <a href="/facts/Spermatophore/TuJFqDxv">spermatophore</a>, which is taken up by the female. Fertilized eggs are laid singly and are usually attached to aquatic plants. This distinguishes them from the free-floating eggs of <a href="/facts/Frog/IxYhbeda">frogs</a> or <a href="/facts/Toad/Reovo8A1">toads</a>, which are laid in clumps or in strings. Plant leaves are usually folded over and attached to the eggs to protect them. The <a href="/facts/Larvae/GKo2FIew">larvae</a>, which resemble fish <a href="/facts/Spawn_(biology)/nYF12vfX">fry</a> but are distinguished by their feathery external gills, hatch out in about three weeks. After hatching, they eat algae, small invertebrates, or other amphibian larvae.
During the subsequent few months, the larvae undergo <a href="/facts/Metamorphosis_(biology)/nKDTSjsK">metamorphosis</a>, during which they develop legs, and the gills are absorbed and replaced by air-breathing lungs.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a> Some species, such as the North American newts, also become more brightly colored during this phase. Once fully metamorphosed, they leave the water and live a terrestrial life, when they are known as "efts."<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a><a class="footnote-ref" id="fnref:12" href="#fn:12">12</a> Only when the eft reaches adulthood will the North American species return to live in water, rarely venturing back onto the land. Conversely, most European species live their adult lives on land and only visit water to breed.<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a>

Development in the <a href="/facts/Northern_crested_newt/7TdJUEbs">northern crested newt</a> (Triturus cristatus)Embryo in jelly capsuleYoung larvaLarva shortly before metamorphosisTerrestrial juvenileNewts lay their eggs on structures such as plants or stones under water. The larvae first develop fore- and later hindlimbs, and are strictly carnivorous. After metamorphosis, juveniles known as efts emerge from the water and live a terrestrial lifestyle.
<h2 id="toxicity">Toxicity</h2>

Many newts produce <a href="/facts/Toxin/11oUNk7n">toxins</a> in their skin secretions as a defence mechanism against predators. Taricha newts of western North America are particularly toxic. The <a href="/facts/Rough-skinned_newt/TIjRgSGY">rough-skinned newt</a> Taricha granulosa of the <a href="/facts/Pacific_Northwest/EjJhETXc">Pacific Northwest</a> produces more than enough <a href="/facts/Tetrodotoxin/hsEJAUwA">tetrodotoxin</a> to kill an adult human, and some <a href="/facts/Indigenous_peoples_of_the_Americas/LG2r6wXm">Native Americans</a> of the Pacific Northwest used the toxin to poison their enemies.<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> However, the toxins are only dangerous if ingested or otherwise enter the body; for example, through a wound. Newts can safely live in the same ponds or streams as frogs and other amphibians or be kept as pets. The only predators of Taricha newts are <a href="/facts/Garter_snakes/g7BvKgsY">garter snakes</a>, some having developed a resistance to the toxin. Most newts can be safely handled, provided the toxins they produce are not ingested or allowed to come in contact with <a href="/facts/Mucous_membrane/oIw0vyel">mucous membranes</a> or breaks in the skin.<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a>

<h2 id="systematics">Systematics</h2>
Newts form one of three <a href="/facts/Subfamily/2QPtfDS4">subfamilies</a> in the family <a href="/facts/Salamandridae/GD8fstEn">Salamandridae</a>, aside <a href="/facts/Salamandrinae/GD8fstEn">Salamandrinae</a> and <a href="/facts/Salamandrininae/E85MpBmR">Salamandrininae</a>.<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a> They comprise most <a href="/facts/Extant_taxon/YK8uj7qU">extant</a> species in the family, roughly 100, which are classified in sixteen genera:<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a>

<ul><li><a href="/facts/Calotriton/3sqv0Jps">Calotriton</a></li>
<li><a href="/facts/Cynops/mzEybeto">Cynops</a> (incl. Hypselotriton)</li>
<li><a href="/facts/Echinotriton/vdL2gY0j">Echinotriton</a></li>
<li><a href="/facts/Euproctus/lhtFTnKf">Euproctus</a></li>
<li><a href="/facts/Ichthyosaura/x85qGDYt">Ichthyosaura</a></li>
<li><a href="/facts/Laotriton/wHamPaUG">Laotriton</a></li>
<li><a href="/facts/Lissotriton/eyLsDy1P">Lissotriton</a></li>
<li><a href="/facts/Neurergus/ms6vp79X">Neurergus</a></li>
<li><a href="/facts/Notophthalmus/sgjs9CDE">Notophthalmus</a></li>
<li><a href="/facts/Ommatotriton/Xd1cd9YC">Ommatotriton</a></li>
<li><a href="/facts/Pachytriton/0Ue3gKV4">Pachytriton</a></li>
<li><a href="/facts/Paramesotriton/BTuUt62n">Paramesotriton</a></li>
<li><a href="/facts/Pleurodeles/AIVfw2jd">Pleurodeles</a></li>
<li><a href="/facts/Taricha/XhUdTUhd">Taricha</a></li>
<li><a href="/facts/Triturus/HqC4zn3R">Triturus</a></li>
<li><a href="/facts/Tylototriton/KSnXLNEW">Tylototriton</a> (incl. Liangshantriton)</li></ul>

Hypselotriton and Liangshantriton are regarded as separate genera by some authors, but this is not unanimous.<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a>
The term "newt" has traditionally been seen as an exclusively functional term for salamanders living in water, and not a <a href="/facts/Clade/XefyYmWn">clade</a>. <a href="/facts/Phylogenetic/bw4rsovt">Phylogenetic</a> analyses have however shown that species in the Salamandridae traditionally called newts do form a <a href="/facts/Monophyletic_group/pD8Yrrn6">monophyletic group</a>.<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a><a class="footnote-ref" id="fnref:20" href="#fn:20">20</a><a class="footnote-ref" id="fnref:21" href="#fn:21">21</a> Other, more distantly related salamander families also contain fully or in part aquatic species, such as the <a href="/facts/Mole_salamanders/DYpmykyr">mole salamanders</a>, the <a href="/facts/Proteidae/1LPmL1x1">Proteidae</a>, or the <a href="/facts/Sirenidae/YTeCafSU">Sirenidae</a>.
Classification of all genera of the Pleurodelinae subfamily after Pyron and Weins,<a class="footnote-ref" id="fnref:22" href="#fn:22">22</a> revised by Mikko Haaramo.

<table><tbody><tr><td></td><td rowspan="2"><table><tbody><tr><td><a href="/facts/Pleurodelinae/2KNMYeSn">Pleurodelinae</a></td><td rowspan="2"><table><tbody><tr><td>Pleurodelini</td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Pleurodeles/AIVfw2jd">Pleurodeles</a> </td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Echinotriton/vdL2gY0j">Echinotriton</a></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><a href="/facts/Tylototriton/KSnXLNEW">Tylototriton</a> </td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr><tr><td>Molgini</td><td rowspan="2"><table><tbody><tr><td>Tarichina</td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Notophthalmus/sgjs9CDE">Notophthalmus</a> </td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><a href="/facts/Taricha/XhUdTUhd">Taricha</a> </td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr><tr><td>Molgina</td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Lissotriton/eyLsDy1P">Lissotriton</a> </td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Neurergus/ms6vp79X">Neurergus</a></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><a href="/facts/Ommatotriton/Xd1cd9YC">Ommatotriton</a></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Calotriton/3sqv0Jps">Calotriton</a></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><a href="/facts/Triturus/HqC4zn3R">Triturus</a> </td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Euproctus/lhtFTnKf">Euproctus</a></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Ichthyosaura_alpestris/pYk7RWGA">Ichthyosaura</a></td></tr><tr><td></td></tr><tr><td>Cynopita</td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Laotriton_laoensis/wHamPaUG">Laotriton</a></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Pachytriton/0Ue3gKV4">Pachytriton</a></td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><table><tbody><tr><td></td><td rowspan="2"><a href="/facts/Cynops/mzEybeto">Cynops</a> </td></tr><tr><td></td></tr><tr><td></td><td rowspan="2"><a href="/facts/Paramesotriton/BTuUt62n">Paramesotriton</a></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table></td></tr><tr><td></td></tr></tbody></table>
<h3>Phylogenetics</h3>
Phylogenetic analyses estimated the origin of the newt subfamily in the <a href="/facts/Late_Cretaceous/pcHa4fBg">Late Cretaceous</a> to <a href="/facts/Eocene/EYgI8Uco">Eocene</a>.<a class="footnote-ref" id="fnref:23" href="#fn:23">23</a> Several <a href="/facts/Prehistoric_amphibian/gbkPGl6g">fossil salamanders</a> have also been referred to the Pleurodelinae, including:<a class="footnote-ref" id="fnref:24" href="#fn:24">24</a>

<ul><li><a href="/facts/Archaeotriton/e3ewWemz">Archaeotriton</a></li>
<li><a href="/facts/Brachycormus/xGhup5RK">Brachycormus</a></li>
<li><a href="/facts/Carpathotriton/2KNMYeSn">Carpathotriton</a></li>
<li><a href="/facts/Chelotriton/tFlRok02">Chelotriton</a></li>
<li><a href="/facts/Koalliella/YnEfsc7g">Koalliella</a></li>
<li><a href="/facts/Palaeopleurodeles/9ltzk7rn">Palaeopleurodeles</a></li></ul>

<h2 id="anatomy-and-physiology">Anatomy and physiology</h2>
<h3>Circulation</h3>
The heart of newts, like that of most amphibians, consists of two atria and one ventricle.<a class="footnote-ref" id="fnref:25" href="#fn:25">25</a> Blood flows from the anterior and posterior caval veins into the right atrium; blood that entered the heart from the left atrium is then expelled out of the ventricle. Newts do not have a <a href="/facts/Coronary_artery/Xsx1dekd">coronary artery</a> on the ventricle, due to circulation that is found in the <a href="/facts/Conus_arteriosus/JkRqm0kL">conus arteriosus</a>. Newts contain a special circulatory adaptation that allows them to survive ventricular penetration: when a newt's ventricle is punctured, the heart will divert the blood directly into an ascending aorta via a duct located between the ventricle and the conus arteriosus. Newts begin to regenerate the ventricle by a thickening of the <a href="/facts/Epicardial/ePd4gkeT">epicardial</a> layer that protrudes to allow the new vessels to form, and conclude with a regeneration of the entire myocardial wall.<a class="footnote-ref" id="fnref:26" href="#fn:26">26</a>
In early stages of development in amphibians, ventilator gas transport and hemoglobin gas transport are independent mechanisms and not yet coupled as they are in adulthood.<a class="footnote-ref" id="fnref:27" href="#fn:27">27</a> In juvenile amphibians, there is no cardiovascular response in conditions of hypoxia.<a class="footnote-ref" id="fnref:28" href="#fn:28">28</a> When newts are induced into anemia, they are able to respire without the need of blood cells.<a class="footnote-ref" id="fnref:29" href="#fn:29">29</a> In T. carnifex, around two weeks after anemia is induced, the newts produced a mass of cells that helps to revitalize the already circulating red blood cell mass.<a class="footnote-ref" id="fnref:30" href="#fn:30">30</a>

<h3>Respiration</h3>
Adult crested newts (Triturus cristus) were found to breathe mainly via the skin but also through the lungs and the <a href="/facts/Buccal_cavity/B1A5DnxB">buccal cavity</a>. Lung breathing is mainly used when there is a lack of oxygen in the water, or at high activity such as during courtship, breeding, or feeding.<a class="footnote-ref" id="fnref:31" href="#fn:31">31</a>
A form of compensatory respiration is the ability to release stored <a href="/facts/Erythrocytes/Kggpq8Jh">erythrocytes</a> when needed, for example under <a href="/facts/Hypoxia_(environmental)/VSSWPNlF">hypoxia</a>.<a class="footnote-ref" id="fnref:32" href="#fn:32">32</a><a class="footnote-ref" id="fnref:33" href="#fn:33">33</a> Spleen size can increase as the temperature declines for adults – in larvae, there is no dramatic change in spleen size.<a class="footnote-ref" id="fnref:34" href="#fn:34">34</a> During hibernation, an increase in liver pigment cells allows for storage of oxygen, as well as other important ions and free radicals.<a class="footnote-ref" id="fnref:35" href="#fn:35">35</a>

<h3>Osmoregulation</h3>
In experiments, dehydrated <a href="/facts/Eastern_newt/pDI59p98">eastern newts</a> were prone to a loss of motor control: After only 22% water weight loss, newts in the aquatic phase lost their ability to remain upright and mobile. However, after adaptation to a terrestrial phase, they could lose 30% before a loss of motor control was recorded. Newts in the terrestrial phase were found to dehydrate much quicker than newts in the aquatic phase, but conversely, during rehydration, dehydrated terrestrial animals will go through water gain 5x faster than dehydrated newts that are in the aquatic phase.<a class="footnote-ref" id="fnref:36" href="#fn:36">36</a>
In the Italian crested newt, it was shown that during winter months, <a href="/facts/Prolactin/NcdqrzFU">prolactin</a> is released into the circulatory system, which drives the newts into the aquatic environment and reduces the active transport of sodium ions.<a class="footnote-ref" id="fnref:37" href="#fn:37">37</a> In contrast to prolactin, which decreases osmotic permeability, <a href="/facts/Vasotocin/NfunQH07">vasotocin</a> increases the permeability and is secreted during the summer months.<a class="footnote-ref" id="fnref:38" href="#fn:38">38</a> Arginine vasotocin not only increases cutaneous water permeability, but promotes increased cutaneous blood flow.<a class="footnote-ref" id="fnref:39" href="#fn:39">39</a>

<h3>Thermoregulation</h3>
Thermoregulation, in combination with seasonal <a href="/facts/Acclimation/YAJ7Us7p">acclimation</a>, describes the major mechanisms of how newts, as <a href="/facts/Ectotherms/vdjXLuQr">ectotherms</a> cope with the changing temperatures existing in their environments. This regulation is most often achieved through behavioral thermoregulation.<a class="footnote-ref" id="fnref:40" href="#fn:40">40</a> They are thermoconformers, which means they will acclimate to their surrounding environmental temperatures.<a class="footnote-ref" id="fnref:41" href="#fn:41">41</a> When there is a large range of environmental temperatures, newts are insensitive to a thermal gradient profile.<a class="footnote-ref" id="fnref:42" href="#fn:42">42</a>
To escape predators, newt larvae have been found to shift their <a href="/facts/Microhabitat/zo1DN2gA">microhabitat</a> to a temperature range that exists outside the predator's preferred temperature range.<a class="footnote-ref" id="fnref:43" href="#fn:43">43</a> Larvae that are in the metamorphosizing stage tend to prefer warmer temperatures than those in the stage following metamorphosis.<a class="footnote-ref" id="fnref:44" href="#fn:44">44</a> Therefore, the larvae in this stage will undergo a much more precise thermoregulation process than those in the intermediate stage.<a class="footnote-ref" id="fnref:45" href="#fn:45">45</a>
Reproductive females of the Italian crested newt were shown to regulate their body temperature more precisely and prefer higher temperatures than non-reproductive females and males.<a class="footnote-ref" id="fnref:46" href="#fn:46">46</a>

<h3>Spermatogenesis</h3>
The newt is regarded as an ideal <a href="/facts/Vertebrate/tT54FSTT">vertebrate</a> model for investigating the mechanism(s) controlling the transition from <a href="/facts/Mitosis/ExxrSUs8">mitosis</a> to <a href="/facts/Meiosis/Pj5Q6nGN">meiosis</a> during <a href="/facts/Spermatogenesis/8u8XNEV6">spermatogenesis</a>.<a class="footnote-ref" id="fnref:47" href="#fn:47">47</a> In the male newt <a href="/facts/Japanese_fire-bellied_newt/MpKoxFbD">Cynopa pyrrhogaster</a>, this transition was shown to involve expression of <a href="/facts/Proliferating_cell_nuclear_antigen/KIBbmpXz">PCNA</a>, a <a href="/facts/DNA_polymerase_delta/JpMmSlfs">DNA polymerase delta</a> auxiliary protein involved in <a href="/facts/DNA_replication/wrU6RuR3">DNA replication</a> and <a href="/facts/DNA_repair/hsURuYYq">DNA repair</a>, as well as <a href="/facts/DMC1_(gene)/dTuoqH22">DMC1</a> protein, a marker for <a href="/facts/Genetic_recombination/uocNH0m7">genetic recombination</a> activity.<a class="footnote-ref" id="fnref:48" href="#fn:48">48</a>

<h3>Susceptibility to pollution</h3>
Larvae, with their great number of lamellae in their gills,<a class="footnote-ref" id="fnref:49" href="#fn:49">49</a> are more susceptible to pollutants than adults. <a href="/facts/Cadmium/wXkV2eIX">Cadmium</a>, a heavy metal released into the environment from industrial and consumer waste, has been shown to be detrimental to the <a href="/facts/Italian_crested_newt/GyzU1Eut">Italian crested newt</a> even at concentrations below Italian and European thresholds, by disrupting the activity of the <a href="/facts/Adrenal_gland/3f8jV5aJ">adrenal gland</a>.<a class="footnote-ref" id="fnref:50" href="#fn:50">50</a> In experiments allowing Italian crested newts to be exposed to <a href="/facts/Nonylphenol/e11QDFsP">nonylphenol</a>, an <a href="/facts/Endocrine_disruptor/Yk2hfnTj">endocrine disruptor</a> common in leakage from sewers, there was a decrease in <a href="/facts/Corticosterone/rcMoEu7f">corticosterone</a> and <a href="/facts/Aldosterone/tjw4dr1u">aldosterone</a>, hormones produced by the <a href="/facts/Adrenal_gland/3f8jV5aJ">adrenal gland</a> and important for stress response.<a class="footnote-ref" id="fnref:51" href="#fn:51">51</a> 

<h2 id="conservation-status">Conservation status</h2>

Although some species, such as the <a href="/facts/Rough-skinned_newt/TIjRgSGY">rough-skinned newt</a> (Taricha granulosa) and <a href="/facts/Eastern_newt/pDI59p98">Eastern newt</a> (Notophthalmus viridescens) in North America or the <a href="/facts/Smooth_newt/6mmyUXCL">smooth newt</a> (Lissotriton vulgaris) in Europe, are still relatively common, populations of newts throughout their distribution range suffer from <a href="/facts/Habitat_loss/pyPMkBCY">habitat loss</a>, <a href="/facts/Habitat_fragmentation/uVIVdT70">fragmentation</a>, and <a href="/facts/Pollution/JRagxumQ">pollution</a>. This affects especially the aquatic breeding sites they depend on, but also their land habitats. Several species, such as the <a href="/facts/Edough_ribbed_newt/wbccXgcL">Edough ribbed newt</a> (Pleurodeles poireti), <a href="/facts/Kaiser%2527s_spotted_newt/FWG5BJmd">Kaiser's spotted newt</a> (Neurergus kaiseri), or the <a href="/facts/Montseny_brook_newt/4eGVzNzK">Montseny brook newt</a> (Calotriton arnoldi) are considered threatened by the <a href="/facts/International_Union_for_Conservation_of_Nature/QwV8JXup">IUCN</a>, and the <a href="/facts/Yunnan_lake_newt/e1AG0r4m">Yunnan lake newt</a> is an example of a newt species that has gone extinct recently.<a class="footnote-ref" id="fnref:52" href="#fn:52">52</a>
Some newt populations in Europe have decreased because of pollution or destruction of their breeding sites and terrestrial habitats, and countries such as the UK have taken steps to halt their declines.<a class="footnote-ref" id="fnref:53" href="#fn:53">53</a><a class="footnote-ref" id="fnref:54" href="#fn:54">54</a> In the UK, they are protected under the <a href="/facts/Wildlife_and_Countryside_Act_1981/JTYq1yn3">Wildlife and Countryside Act 1981</a> and the Habitat Regulations Act 1994. It is illegal to catch, possess, or handle <a href="/facts/Great_Crested_Newt/7TdJUEbs">great crested newts</a> without a licence, or to cause them harm or death, or to disturb their habitat in any way. The <a href="/facts/IUCN_Red_List/8gemqCLu">IUCN Red List</a> categorises the species as ‘lower risk’<a class="footnote-ref" id="fnref:55" href="#fn:55">55</a><a class="footnote-ref" id="fnref:56" href="#fn:56">56</a>
Although the other UK species, the <a href="/facts/Smooth_newt/6mmyUXCL">smooth newt</a> and <a href="/facts/Palmate_newt/dMT7la5s">palmate newt</a> are not listed, the sale of either species is prohibited under the Wildlife and Countryside Act, 1981.<a class="footnote-ref" id="fnref:57" href="#fn:57">57</a>
In Europe, nine newts are listed as "strictly protected fauna species" under appendix II of the <a href="/facts/Convention_on_the_Conservation_of_European_Wildlife_and_Natural_Habitats/LpzNs4XG">Convention on the Conservation of European Wildlife and Natural Habitats</a>:<a class="footnote-ref" id="fnref:58" href="#fn:58">58</a>

<ul><li><a href="/facts/Calotriton_asper/5P5qR0dk">Calotriton asper</a></li>
<li><a href="/facts/Euproctus_montanus/PCzPB5xe">Euproctus montanus</a></li>
<li><a href="/facts/Euproctus_platycephalus/mDEy6VPz">Euproctus platycephalus</a></li>
<li><a href="/facts/Lissotriton_italicus/gxMf64dh">Lissotriton italicus</a></li>
<li><a href="/facts/Lissotriton_montandoni/0V6x6bhS">Lissotriton montandoni</a></li>
<li><a href="/facts/Triturus_carnifex/GyzU1Eut">Triturus carnifex</a></li>
<li><a href="/facts/Triturus_cristatus/7TdJUEbs">Triturus cristatus</a></li>
<li><a href="/facts/Triturus_dobrogicus/maDJ2ysJ">Triturus dobrogicus</a></li>
<li><a href="/facts/Triturus_karelinii/dzJFQJ2s">Triturus karelinii</a></li></ul>

The remaining European species are listed as "protected fauna species" under appendix III.<a class="footnote-ref" id="fnref:59" href="#fn:59">59</a>

<h2 id="as-bioindicators">As bioindicators</h2>
Newts, as with salamanders in general and other amphibians, serve as <a href="/facts/Bioindicators/smsha83y">bioindicators</a> because of their thin, sensitive skin and evidence of their presence (or absence) can serve as an indicator of the health of the environment. Most species are highly sensitive to subtle changes in the <a href="/facts/PH/RnSv8D7y">pH</a> level of the streams and lakes where they live. Because their skin is permeable to water, they absorb oxygen and other substances they need through their skin. Scientists study the stability of the amphibian population when studying the water quality of a particular body of water.

<h2 id="as-pets">As pets</h2>
<a href="/facts/Chinese_warty_newt/0bJpQPjl">Chinese warty newts</a>, <a href="/facts/Chinese_fire_belly_newt/Al06QWYl">Chinese fire belly newts</a>, <a href="/facts/Eastern_newt/pDI59p98">eastern newts</a>, <a href="/facts/Pachytriton/0Ue3gKV4">paddletail newts</a>, <a href="/facts/Japanese_fire_belly_newt/MpKoxFbD">Japanese fire belly newts</a>, <a href="/facts/Chuxiong_fire-bellied_newt/VdESMC8T">Chuxiong fire-bellied newts</a>, <a href="/facts/Triturus/HqC4zn3R">Triturus</a> species, <a href="/facts/Emperor_newt/CI4R29de">emperor newts</a>, <a href="/facts/Spanish_ribbed_newt/7XAA1lkC">Spanish ribbed newts</a> (<a href="/facts/Leucistic/yJ9SXcLc">leucistic</a> genes exist), and <a href="/facts/Red-tailed_knobby_newt/Q78YM3rz">red-tailed knobby newts</a> are some commonly seen newts in the pet trade. Some newts rarely seen in the pet trade are <a href="/facts/Rough-skinned_newt/TIjRgSGY">rough-skinned newts</a>, <a href="/facts/Kaiser%2527s_spotted_newt/FWG5BJmd">Kaiser's spotted newts</a>, <a href="/facts/Ommatotriton/Xd1cd9YC">banded newts</a> and <a href="/facts/Yellow-spotted_newt/HhTQkyeV">yellow-spotted newts</a>.[original research?]

<h2 id="external-links">External links</h2>

Look up newt in Wiktionary, the free dictionary.

Look up newt or eft in Wiktionary, the free dictionary.

<ul><li> Data related to Pleurodelinae at Wikispecies</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Oxford English Dictionary; Anon. "Online etymological dictionary". Douglas Harper. Retrieved 9 October 2013. <a href="/wiki/Oxford_English_Dictionary" target="_blank">/wiki/Oxford_English_Dictionary</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">The Gentleman's Magazine, and Historical Chronicle, Volume 47 (1777), p. 321. <a href="https://books.google.com/books?id=9ntIAAAAYAAJ&pg=PA321" target="_blank">https://books.google.com/books?id=9ntIAAAAYAAJ&pg=PA321</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">John Wilkins, An Essay Towards a Real Character, and a Philosophical Language (1668), p. 161. Gilbert White, The Natural History and Antiquities of Selborne, in the County of Southampton (1789) p. 50: "the water-eft, or newt, is only the larva of the land-eft, as tadpoles are of frogs". Archibald Constable, Constable's miscellany of original and selected publications in the various departments of literature, science, & the arts, Volume 45 (1829), p. 63: "the salamandra aquatica of Hay, (the water-newt, or eft)". <a href="/wiki/John_Wilkins" target="_blank">/wiki/John_Wilkins</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">John Jamieson, An etmological dictionary of the Scottish language (1818). <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Wolfgang Pfeifer (ed.), Etymologisches Wörterbuch des Deutschen. Deutscher Taschenbuch Verlag, Munich 1997 (revised edition of Akademie Verlag, Munich 1989 and 1993), p. 265, s.v. Eidechse. Pfeifer gives the second element as germ. *þahsjō(n), relating it to Middle High German dehse "distaff", so that both animals (lizard and badger) were parallelized due to their common, spindle-shaped bodies. <a href="http://www.dwds.de/?qu=Eidechse" target="_blank">http://www.dwds.de/?qu=Eidechse</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Henry George Liddell, Robert Scott, A Greek-English Lexicon. <a href="https://www.perseus.tufts.edu/hopper/morph?l=kordu%2Flos&la=greek&can=kordu%2Flos0#lexicon" target="_blank">https://www.perseus.tufts.edu/hopper/morph?l=kordu%2Flos&la=greek&can=kordu%2Flos0#lexicon</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Alain Dubois and Roger Bour, The nomenclatural status of the nomina of amphibians and reptiles created by Garsault (1764), with a parsimonious solution to an old nomenclatural problem regarding the genus Bufo (Amphibia, Anura), comments on the taxonomy of this genus, and comments on some nomina created by Laurenti (1768) Archived 2014-01-09 at the Wayback Machine, Zootaxa 2447 (2010), 1–52. <a href="http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Dubois_and_Bour_2010a.pdf" target="_blank">http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Dubois_and_Bour_2010a.pdf</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Collins, J. T.; Conant, R.; Stebbins, R. C.; Peterson, R. T. (1999). Peterson First Guide to Reptiles and Amphibians. Houghton Mifflin Harcourt. ISBN 978-0-395-97195-6. <a href="978-0-395-97195-6" target="_blank">978-0-395-97195-6</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">"Shannon Odelberg". Molecular Biology Program - Bioscience Graduate Studies. University of Utah. Archived from the original on 2006-09-02. <a href="https://web.archive.org/web/20060902234319/http://www.bioscience.utah.edu/mb/mbFaculty/odelberg/odelberg.html" target="_blank">https://web.archive.org/web/20060902234319/http://www.bioscience.utah.edu/mb/mbFaculty/odelberg/odelberg.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">"Amphibians - body, used, water, process, Earth, life, characteristics, form, animals, oxygen, air, plant, change, History, Characteristics, Life cycle, Three major groupings". Scienceclarified.com. 2009-10-13. Retrieved 2013-06-06. <a href="http://www.scienceclarified.com/Al-As/Amphibians.html" target="_blank">http://www.scienceclarified.com/Al-As/Amphibians.html</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">"Cambridge City Council: Local Nature Reserves". Lnr.cambridge.gov.uk. 2005-07-25. Archived from the original on 2013-07-23. Retrieved 2013-06-06. <a href="https://web.archive.org/web/20130723214517/http://lnr.cambridge.gov.uk/news/article.asp?ItemID=285" target="_blank">https://web.archive.org/web/20130723214517/http://lnr.cambridge.gov.uk/news/article.asp?ItemID=285</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Brockes, J; Kumar, A (Jan 2005). "Newts". Current Biology. 15 (2): R42 – R44. Bibcode:2005CBio...15..R42B. doi:10.1016/j.cub.2004.12.049. PMID 15668151. <a href="https://doi.org/10.1016%2Fj.cub.2004.12.049" target="_blank">https://doi.org/10.1016%2Fj.cub.2004.12.049</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">"BBC Nature - Great crested newt videos, news and facts". Bbc.co.uk. Retrieved 2013-06-06. <a href="https://www.bbc.co.uk/nature/wildfacts/factfiles/478.shtml" target="_blank">https://www.bbc.co.uk/nature/wildfacts/factfiles/478.shtml</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">"Caudata Culture Articles - Newt Toxins". Caudata.org. Retrieved 2013-06-06. <a href="http://www.caudata.org/cc/articles/toxin2.shtml" target="_blank">http://www.caudata.org/cc/articles/toxin2.shtml</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">"Caudata Culture Articles - Newt Toxins". Caudata.org. Retrieved 2013-06-06. <a href="http://www.caudata.org/cc/articles/toxin2.shtml" target="_blank">http://www.caudata.org/cc/articles/toxin2.shtml</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">Pyron, R.A.; Weins, J.J. (2011). "A large-scale phylogeny of Amphibia including over 2800 species, and a revised classification of advanced frogs, salamanders, and caecilians" (PDF). Molecular Phylogenetics and Evolution. 61 (2): 543–853. doi:10.1016/j.ympev.2011.06.012. PMID 21723399. <a href="http://home.gwu.edu/~rpyron/publications/Pyron_Wiens_2011.pdf" target="_blank">http://home.gwu.edu/~rpyron/publications/Pyron_Wiens_2011.pdf</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">Frost, D.R. (2016). "Pleurodelinae. Amphibian Species of the World: an Online Reference. Version 6.0". New York: American Museum of Natural History. Retrieved 2019-10-11. <a href="http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Caudata/Salamandridae/Pleurodelinae" target="_blank">http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Caudata/Salamandridae/Pleurodelinae</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">Frost, D.R. (2016). "Pleurodelinae. Amphibian Species of the World: an Online Reference. Version 6.0". New York: American Museum of Natural History. Retrieved 2019-10-11. <a href="http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Caudata/Salamandridae/Pleurodelinae" target="_blank">http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Caudata/Salamandridae/Pleurodelinae</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Zhang, Peng; Papenfuss, Theodore J.; Wake, Marvalee H.; Qu, Lianghu; Wake, David B. (2008). "Phylogeny and biogeography of the family Salamandridae (Amphibia: Caudata) inferred from complete mitochondrial genomes" (PDF). Molecular Phylogenetics and Evolution. 49 (2): 586–597. doi:10.1016/j.ympev.2008.08.020. ISSN 1055-7903. PMID 18801447. Archived from the original (PDF) on 2017-02-02. Retrieved 2016-08-29. <a href="https://web.archive.org/web/20170202004738/https://bsp.berkeley.edu/labs/mwake/papers/206.pdf" target="_blank">https://web.archive.org/web/20170202004738/https://bsp.berkeley.edu/labs/mwake/papers/206.pdf</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">Pyron, R.A.; Weins, J.J. (2011). "A large-scale phylogeny of Amphibia including over 2800 species, and a revised classification of advanced frogs, salamanders, and caecilians" (PDF). Molecular Phylogenetics and Evolution. 61 (2): 543–853. doi:10.1016/j.ympev.2011.06.012. PMID 21723399. <a href="http://home.gwu.edu/~rpyron/publications/Pyron_Wiens_2011.pdf" target="_blank">http://home.gwu.edu/~rpyron/publications/Pyron_Wiens_2011.pdf</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">Frost, D.R. (2016). "Pleurodelinae. Amphibian Species of the World: an Online Reference. Version 6.0". New York: American Museum of Natural History. Retrieved 2019-10-11. <a href="http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Caudata/Salamandridae/Pleurodelinae" target="_blank">http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Caudata/Salamandridae/Pleurodelinae</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">Pyron, R.A.; Weins, J.J. (2011). "A large-scale phylogeny of Amphibia including over 2800 species, and a revised classification of advanced frogs, salamanders, and caecilians" (PDF). Molecular Phylogenetics and Evolution. 61 (2): 543–853. doi:10.1016/j.ympev.2011.06.012. PMID 21723399. <a href="http://home.gwu.edu/~rpyron/publications/Pyron_Wiens_2011.pdf" target="_blank">http://home.gwu.edu/~rpyron/publications/Pyron_Wiens_2011.pdf</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">Zhang, Peng; Papenfuss, Theodore J.; Wake, Marvalee H.; Qu, Lianghu; Wake, David B. (2008). "Phylogeny and biogeography of the family Salamandridae (Amphibia: Caudata) inferred from complete mitochondrial genomes" (PDF). Molecular Phylogenetics and Evolution. 49 (2): 586–597. doi:10.1016/j.ympev.2008.08.020. ISSN 1055-7903. PMID 18801447. Archived from the original (PDF) on 2017-02-02. Retrieved 2016-08-29. <a href="https://web.archive.org/web/20170202004738/https://bsp.berkeley.edu/labs/mwake/papers/206.pdf" target="_blank">https://web.archive.org/web/20170202004738/https://bsp.berkeley.edu/labs/mwake/papers/206.pdf</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
<li id="fn:24">Marjanović, David; Witzmann, Florian (2015). "An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids". PLOS ONE. 10 (9): e0137068. Bibcode:2015PLoSO..1037068M. doi:10.1371/journal.pone.0137068. ISSN 1932-6203. PMC 4589347. PMID 26421432.
 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4589347" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4589347</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></li>
<li id="fn:25">(Miyachi, Y. 2011. The Unusual Circulation of the Newt Heart after Ventricular Injury and Its Implications for Regeneration. Anatomy Research International:1-7). <a href="#fnref:25" class="footnote-back-ref">↩</a></li>
<li id="fn:26">(Miyachi, Y. 2011. The Unusual Circulation of the Newt Heart after Ventricular Injury and Its Implications for Regeneration. Anatomy Research International:1-7). <a href="#fnref:26" class="footnote-back-ref">↩</a></li>
<li id="fn:27">(Pelster, B. 1999. Environmental Influences on the Development of the Cardiac System in Fish and Amphibians. Comparative Biochemistry and Physiology Part A 124:407-412) <a href="#fnref:27" class="footnote-back-ref">↩</a></li>
<li id="fn:28">(Pelster, B. 1999. Environmental Influences on the Development of the Cardiac System in Fish and Amphibians. Comparative Biochemistry and Physiology Part A 124:407-412) <a href="#fnref:28" class="footnote-back-ref">↩</a></li>
<li id="fn:29">(Casale. G.P, Khairallah. E. A., Grasso. J. A. 1980. An Analysis of Hemoglobin Synthesis in Erythropoietic Cells. Developmental Biology 80:107-119. ) <a href="#fnref:29" class="footnote-back-ref">↩</a></li>
<li id="fn:30">(Casale. G.P, Khairallah. E. A., Grasso. J. A. 1980. An Analysis of Hemoglobin Synthesis in Erythropoietic Cells. Developmental Biology 80:107-119. ) <a href="#fnref:30" class="footnote-back-ref">↩</a></li>
<li id="fn:31">(Eddy, F. B., P. McDonald. 1978. Aquatic respiration of The Crested Newt Triturus Cristatus. Comparative Biochemical Physiology. 59: 85–88) <a href="#fnref:31" class="footnote-back-ref">↩</a></li>
<li id="fn:32">(Giuliano Frangioni, Mario Santoni, Stefano Bianchi, Marco Franchi, Giancarlo Fuzzi, Stefano
Marcaccini, Carlo Varlani, Gianfranco Borgioli. 2006. Function of the Hepatic Melanogenesis in the Newt, Triturus Carnifex. Journal of Experimental Zoology. 303A:123-131.) <a href="#fnref:32" class="footnote-back-ref">↩</a></li>
<li id="fn:33">(Frangioni, G., G. Borgioli. 1996. Variations in blood pressure of newts according to their
respiratory conditions. Italian Journal of Zoology. 63:3, 201–206). <a href="#fnref:33" class="footnote-back-ref">↩</a></li>
<li id="fn:34">(Frangioni, G., G Borgioli. 1997. Blood and splenic respiratory compensation in larval newts. Italian Journal of Zoology. 64:3, 221–226) <a href="#fnref:34" class="footnote-back-ref">↩</a></li>
<li id="fn:35">(Barni et al. 1999) <a href="#fnref:35" class="footnote-back-ref">↩</a></li>
<li id="fn:36">P. Walters, L. Greenwald. 1977. Physiological adaptations of aquatic newts (Notophtalmus viridescens) to a terrestrial environment. Physiological Zoology. 50(2): 88–98. <a href="#fnref:36" class="footnote-back-ref">↩</a></li>
<li id="fn:37">Lodi, G., Biciotti, M., and Viotto, B. 1981. Cutaneous Osmoregulation in Triturus cristatus carnifex (Laur.) (Urodela). General and Comparative Endocrinology 46: 452–457. <a href="#fnref:37" class="footnote-back-ref">↩</a></li>
<li id="fn:38">Brown, M., Brown, S., Bisceglio, I., and Lemke, S. 1983. Breeding Condition, Temperature, and the Regulation of Salt and Water by Pituitary Hormones in the Red-Spotted Newt, Notophthalmus viridescens. General and Comparative Endocrinology 51, 292–302. <a href="#fnref:38" class="footnote-back-ref">↩</a></li>
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</ol>

Newt open-in-new

Newt