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{{Short description|Genus of amphibians}}
{{More citations needed|date=October 2008}}
{{Automatic taxobox
| name=
| image= SpottedSalamander.jpg
| image_caption=[[Spotted salamander]] (''Ambystoma maculatum'')
Line 8 ⟶ 9:
}}
The '''mole salamanders''' ([[genus]] '''''Ambystoma''''') are a group of [[Salamandroidea|advanced salamander]]s endemic to North America. The group has become famous due to the presence of the [[axolotl]] (''A. mexicanum''), widely used in research due to its [[neoteny|paedomorphosis]], and the [[tiger salamander]] (''A. tigrinum, A. mavortium'') which is the official amphibian of many US states, and often sold as a pet.
==General description==
Line 17 ⟶ 18:
The larvae of some species (especially those in the south, and tiger salamanders) can reach their adult size before undergoing [[Metamorphosis (biology)|metamorphosis]]. During metamorphosis, the gills of the larvae disappear, as do the fins. Their tails, skin, and limbs become thicker, and the eyes develop lids. Their lungs become fully developed, allowing for a fully terrestrial existence.
Some species of mole salamanders (as well as populations of normally terrestrial species) are [[Neoteny|neotenic]] (retaining their larval form into adulthood). The most famous example is the [[axolotl]]. They cannot produce [[thyroxine]], so their only means of metamorphosis is mainly through the outside injection of it. This usually shortens the lifespan of the salamander.
==Tiger salamander complex==
{{Unreferenced section|date=March 2024}}
[[File:Barred Tiger Salamander Tennoji.jpg|thumb|right|[[Tiger salamander]] (''Ambystoma tigrinum'')]]
The presence of [[neotenic]] populations near those with large larvae has made it difficult to identify mole salamander species. The [[tiger salamander]] complex was previously considered a single species ranging from Canada to Mexico, falling under the name ''A. tigrinum''. Despite differences in coloration and larvae, tiger salamanders were found throughout their unbroken [[range (biology)|range]], which made it difficult to delineate subspecies, let alone elevate any populations to species status. In morphological terms, tiger salamanders are all very similar, with large heads, small eyes, and thick bodies. This is probably because tiger salamanders have the primitive morphology of mole salamanders. They are also the largest of the mole salamanders, and have very large larvae. All populations have similar lifestyles, and their lifecycles are identical. However, when one looks at tiger salamander populations distant from each other, different species within this complex become apparent. The ranges of these potential species overlap, and hybridization occurs, blurring the lines between species.
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Several subspecies of ''A. tigrinum'' were named to deal with this problem. Recently, the [[barred tiger salamander]] (''A. mavortium'') was elevated to species status—covering the tiger salamander populations in the western and central United States. Several distinct subspecies still exist in ''A. mavortium'', which may be elevated to species status at some point in the future. The [[California tiger salamander]] (''A. californiense'') has also been elevated out of ''A. tigrinum,'' and is actually very distantly related to all other mole salamander species. The [[Plateau tiger salamander]] (''A. velasci'') was elevated out of ''A. tigrinum'' through genetic analysis in 1997. All accounts referring to the [[axolotl]] (''A. mexicanum'') as a close relative of ''A. tigrinum'' are now considered wrong, as they are now separated by both geography and many species between. Instead, it is ''A. velasci'', which shares the axolotl's habitat, and is probably closely related to it. The Plateau tiger salamander was probably the parent of most of the [[neoteny|neotenic]] species, which raises the possibility that ''A. velasci'' is paraphyletic, and may be broken up into more species in the future.
== Hybrid all-female populations ==
{{Split|date=April 2024|Unisexual salamander|discuss=Talk:Mole salamander#Split all-female lineage into new article}}
Unisexual (all-female) populations of ambystomatid salamanders are widely distributed across the Great Lakes region and northeastern North America. The females require sperm from a co‑occurring, related species to fertilize their eggs and initiate development. Usually<ref Name=Bi2008>{{cite journal |author1=Bi, Ke |author2=Bogart, James P. |author3=Fu, Jinzhong |year=2008 |title=The prevalence of genome replacement in unisexual salamanders of the genus Ambystoma (Amphibia, Caudata) revealed by nuclear gene genealogy |journal=[[BMC Evolutionary Biology]] |volume=8 |issue=1 |page=158 |doi=10.1186/1471-2148-8-158 |issn=1471-2148 |pmid=18498635 |pmc=2413238 |doi-access=free |bibcode=2008BMCEE...8..158B }}</ref> the eggs then discard the sperm genome and develop asexually (i.e., [[gynogenesis]], with [[Parthenogenesis#Types and mechanisms|premeiotic doubling]]); however, they may incorporate the genome from the sperm into the resulting offspring.<ref name=Bogart2007>{{cite journal |author1=Bogart, James P. |author2=Bi, Ke |author3=Jinzong Fu |author4=Noble, Daniel W.A. |author5=Niedzwiecki, John |date=February 2007 |title=Unisexual salamanders (genus ''Ambystoma'') present a new reproductive mode for eukaryotes |journal=[[Genome (journal)|Genome]] |volume=50 |issue=2 |pages=119–136 |doi=10.1139/g06-152 |issn=0831-2796 |pmid=17546077}}</ref> Sperm incorporation commonly<ref name=Bi2008/> takes the form of genome addition (resulting in [[ploidy]] elevation in the offspring), or genome replacement, wherein one of the maternal genomes is discarded. This unique mode of reproduction has been termed [[kleptogenesis]] by Bogart and colleagues.<ref name=Bogart2007/> This is in contrast to [[hybridogenesis]], where the maternal genomes are passed hemiclonally and the paternal genome is discarded every generation before the egg matures and reacquired from the sperm of another species.
The nuclear DNA of the unisexuals generally comprises genomes from up to five species:<ref name=Bogart2009>{{cite journal |author1=Bogart, J.P. |author2=Bartoszek, J. |author3=Noble, D.W.A. |author4=Bi, K. |date=2009-07-29 |df=dmy-all |title=Sex in unisexual salamanders: discovery of a new sperm donor with ancient affinities |journal=[[Heredity (journal)|Heredity]] |volume=103 |issue=6 |pages=483–493 |doi=10.1038/hdy.2009.83 |doi-access=free |pmid=19639004 |issn=0018-067X}}</ref> the [[blue-spotted salamander]] (''A. laterale''), [[Jefferson salamander]] (''A. jeffersonianum''), [[small-mouthed salamander]] (''A. texanum''), [[streamside salamander]] (''A. barbouri''), and tiger salamander (''A. tigrinum''), denoted respectively as L, J, Tx, B, and Ti. This flexibility results in a large number of possible nuclear biotypes (genome combinations) in the unisexuals. For example, an LJJ individual would be a triploid with one ''A. laterale'' genome and two ''A. jeffersonianum'' genomes, while an LTxJTi individual would be a tetraploid with genomes from four species. Because they have hybrid genomes, unisexual salamanders are a cryptic species with morphology similar to coexisting species. For example, LLJs look like blue-spotted salamanders and LJJs look like Jefferson salamanders. Silvery salamanders LJJ (''A. platineum''), Tremblay's salamanders LLJ (''A. tremblayi''), and Kelly's Island salamanders LTxTx and LTxTi (''A. nothagenes'') were initially described as species. Species names were later dropped for all unisexual salamanders because of the complexity of their genomes. The offspring of a single mother may have different genome complements;<ref name=Bogart2007/> for example, a single egg mass may have both LLJJ and LJJ larvae.
Despite the complexity of the nuclear genome, all unisexuals form a [[monophyletic]] group based on their [[mitochondrial DNA]]. The maternal ancestor of the unisexual ambystomatids was most closely related to the [[streamside salamander]], with the original hybridization likely occurring 2.4~3.9 million years ago,<ref name=Bogart2007/> making it the oldest known lineage of all-female vertebrates.<ref name=Bi2010>{{cite journal |author1=Bi, Ke |author2=Bogart, James P. |year=2010 |title=Time and time again: Unisexual salamanders (genus ''Ambystoma'') are the oldest unisexual vertebrates |journal=[[BMC Evolutionary Biology]] |volume=10 |issue=1 |pages=238 |pmid=20682056 |pmc=3020632 |doi=10.1186/1471-2148-10-238 |issn=1471-2148 |doi-access=free |bibcode=2010BMCEE..10..238B }}</ref> The hybridization was most probably with an ''A. laterale''. All known unisexuals have at least one ''A. laterale'' genome<ref name=Bogart2009/> and this is thought to be essential for unisexuality. However, the ''A. laterale'' genome has been replaced several times, independently, in each of the lineages by matings with ''A. laterale''.
==Limb regeneration==
''Ambystoma mexicanum'', a [[neoteny|neotenic]] [[salamander]] with exceptional [[regeneration (biology)|regenerative capabilities]] is one of the principal models for studying limb regeneration.<ref name="Garcia-Lepe2021">García-Lepe UO, Cruz-Ramírez A, Bermúdez-Cruz RM. DNA repair during regeneration in Ambystoma mexicanum. Dev Dyn. 2021 Jun;250(6):788-799. doi: 10.1002/dvdy.276. Epub 2020 Dec 17. PMID 33295131</ref> Limb regeneration involves the propagation of a mass of low differentiated and highly proliferative cells termed the [[blastema]].<ref name = Garcia-Lepe2021/><ref name="Garcia-Lepe2022">García-Lepe UO, Torres-Dimas E, Espinal-Centeno A, Cruz-Ramírez A, Bermúdez-Cruz RM. Evidence of requirement for homologous-mediated DNA repair during Ambystoma mexicanum limb regeneration. Dev Dyn. 2022 Jun;251(6):1035-1053. doi: 10.1002/dvdy.455. Epub 2022 Jan 25. PMID 35040539</ref> During limb regeneration, blastema cells experience [[DNA damage (naturally occurring)|DNA double-strand breaks]] and thus require [[homologous recombination]], a form of [[DNA repair]] that deals with double-strand breaks.<ref name = Garcia-Lepe2022/>
==Taxonomy==
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''Rhyacosiredon'' was previously considered a separate genus within the family Ambystomatidae. However, cladistic analysis of the mole salamanders found the existence of ''Rhyacosiredon'' makes ''Ambystoma'' [[paraphyletic]], since the species are more closely related to some ''Ambystoma'' species than those species are to others in ''Ambystoma''. The stream-type morphology of these salamanders (which includes larvae and [[neoteny|neotenes]] with short gills and thicker [[gular fold]]s) may have led to their misclassification as a different genus.
The genus name ''Ambystoma'' was given by [[Johann Jakob von Tschudi]] in 1839,<ref name=tschudi>{{cite journal|last1=Tschudi|first1=Johann Jakob|title=Classification der Batrachier, mit Berucksichtigung der Fossilen Thiere dieser Abtheilung der Reptilien|journal=Mémoires de la Société des Sciences Naturelles de Neuchatel|date=1839|volume=2|issue=4|pages=57, 92|url=https://www.biodiversitylibrary.org/page/10595602}}</ref> and is traditionally translated as "cup-mouth",{{Citation needed|date=January 2009}}. Tschudi did not provide a derivation for the name, and many thought that he intended the name ''Amblystoma'', "blunt-mouth." Occasionally, old specimens and documents use the name ''Amblystoma''. Writing in 1907, [[Leonhard Stejneger]] offered a derivation of ''Ambystoma'' based on the contraction of a Greek phrase meaning "to cram into the mouth,"<ref name="stejneger">{{cite journal|last1=Stejneger|first1=Leonhard|title=Herpetology of Japan and Adjacent Territory|journal=Bulletin of the United States National Museum|date=1907|volume=58|page=24|url=https://www.biodiversitylibrary.org/page/7734859
|hdl=2027/mdp.39015006820313|hdl-access=free}}</ref><ref name="lyon">{{cite journal|last1=Lyon Jr.|first1=M. W.|title=''Ambystoma'' not ''Amblystoma''|journal=Science|date=30 June 1916|volume=43|issue=1122|pages=929–930|jstor=1639383|doi=10.1126/science.43.1122.929-a|pmid=17793100}}</ref> but others have not found this explanation convincing.<ref name="scott">{{cite journal|last1=Scott|first1=Charles P. G.|title=''Amblystoma'' not ''Ambystoma''|journal=Science|date=1 September 1916|volume=44|issue=1131|pages=309–311|jstor=1642899|url=https://zenodo.org/record/2284246|doi=10.1126/science.44.1131.309-a|pmid=17840073|s2cid=5490505 }}</ref> In the absence of clear evidence that Tschudi committed a [[lapsus]], the name given in 1839 stands.
==Species==
This genus contains 32 [[species]], listed below, the newest being ''A. bishopi''. Some ''Ambystoma'' species are [[Terrestrial animal|Terrestrial]], others are [[Neoteny#Neoteny in Other Species|neotenic]], and some species have established populations of both neotenic and terrestrial forms.
{|cellspacing=0 cellpadding=5 border=1 class="wikitable mw-collapsible" style="text-align: center; border-collapse: collapse;"
!bgcolor="#f0f0f0"|Image
!bgcolor="#f0f0f0"|Species and author
!bgcolor="#f0f0f0"|Common name
!bgcolor="#f0f0f0"|Distribution
!bgcolor="#f0f0f0"|Lifestyle
!bgcolor="#f0f0f0"|[[IUCN]] status
|-
| [[File:Ambystoma altamirani cropped.jpg|100px]]
|''A. altamirani''
[[Alfredo Dugès|Dugès]], 1895
|[[Mountain stream salamander]], Achoque
|style="width:35%"|Central Mexico, west and south of the [[Valley of Mexico]]
|Terrestrial and neotenic
|[[File:Fl_mammals_en.svg]]
|-
|
|''A. amblycephalum''
[[Edward Harrison Taylor|Taylor]], 1940
|[[Blunt-headed salamander]]
|West-central Mexico ([[Michoacán|Michoacán state]]), near [[Morelia]]
|Terrestrial and neotenic
|[[File:Fl_mammals_cr.svg]]
|-
|[[File:Ambystoma andersoni.jpg|150x150px]]
|''A. andersoni''
([[Ronald A. Brandon|Brandon]] and [[Salome Litwin Krebs|Krebs]], 1984)
|[[Anderson's salamander]]
|West-central Mexico ([[Michoacán|Michoacán state]]), [[Laguna de Zacapu]]
|Neotenic
|[[File:Fl_mammals_cr.svg]]
|-
|[[File:Ringed Salamander (Ambystoma annulatum) (24088441718).jpg|200x200px]]
|''[[Ringed salamander|A. annulatum]]''
[[Edward Drinker Cope|Cope]], 1886
|[[Ringed salamander]]
|South-central United States ([[Arkansas]], [[Illinois]], [[Missouri]], [[Oklahoma]]), [[Ozarks|Ozark Plateau]] and [[Ouachita Mountains]]
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Ambystoma barbouri 1.jpeg|200x200px]]
|''A. barbouri''
Kraus & Petranka, 1989
|[[Streamside salamander]]
|South-midwest United States ([[Indiana]], [[Kentucky]], [[Ohio]], [[Tennessee]], [[West Virginia]])
|Terrestrial
|[[File:Fl_mammals_nt.svg]]
|-
|
|''A. bishopi''
[[Gregory Pauly|Pauly]], [[Oliver Piskurek|Piskurek]] & [[Bradley Shaffer|Shaffer]], 2007
|[[Reticulated flatwoods salamander]]
|Southeast United States ([[Florida Panhandle]] and southernmost [[Georgia (U.S. state)|Georgia]]), west of the [[Apalachicola River|Apalachicola]]-[[Flint River (Georgia)|Flint River]]
|Terrestrial
|[[File:Fl_mammals_vu.svg]]
|-
|
|''A. bombypellum''
([[Edward Harrison Taylor|Taylor]], 1940)
|[[Delicate-skinned salamander]]
|Central Mexico ([[State of Mexico]]) near [[Jilotepec de Abasolo|Jilotepec]]
|Terrestrial
|[[File:Fl_mammals_dd.svg]]
|-
|[[File:Ambystoma californiense 213170.jpg|200x200px]]
|''A. californiense''
[[John Edward Gray|Gray]], 1853
|[[California tiger salamander]]
|[[Central Valley (California)|Central Valley]] of [[California]]
|Terrestrial
|[[File:Fl_mammals_vu.svg]]
|-
|[[File:Ambystoma cingulatum USGS.jpg|200x200px]]
|''A. cingulatum''
Cope, 1868
|[[Frosted flatwoods salamander]]
|Southeast United States (southern [[South Carolina]] and [[Georgia (U.S. state)|Georgia]] south to northern [[Florida]])
|Terrestrial
|[[File:Fl_mammals_vu.svg]]
|-
|[[File:MX. Achoque o ajolote de Pátzcuaro - Ambystoma dumerilii (3).jpg|200x200px]]
|''A. dumerilii''
([[Alfredo Dugès|Dugès]], 1870)
|[[Lake Patzcuaro salamander|Lake Pátzcuaro salamander]], Achoque
|West-central Mexico ([[Michoacán|Michoacán state]]), [[Lake Pátzcuaro]]
|Neotenic
|[[File:Fl_mammals_cr.svg]]
|-
|[[File:Ambystoma flavipiperatum 67940860 (cropped).jpg|200x200px]]
|''A. flavipiperatum''
[[James R. Dixon|Dixon]], 1963
|[[Yellow-peppered salamander]], Ajolote de Chapala
|West-central Mexico ([[Jalisco]])
|Terrestrial
|[[File:Fl_mammals_en.svg]]
|-
|[[File:Ambystoma gracile - Nordwestlicher Querzahnmolch 183623689.jpg|200x200px]]
|''A. gracile''
([[Baird (taxonomy)|Baird]], 1859)
|[[Northwestern salamander]]
|Northwest North America (southernmost [[Alaska]] to northern [[California]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|
|''A. granulosum''
[[Edward Harrison Taylor|Taylor]], 1944
|[[Granular salamander]], Ajolote
|Central Mexico ([[State of Mexico]]) near [[Toluca]]
|Terrestrial
|[[File:Fl_mammals_en.svg]]
|-
|[[File:Ambystoma jeffersonianum 184652332.jpg|200x200px]]
|''A. jeffersonianum''
([[Jacob Green (naturalist)|Green]], 1827)
|[[Jefferson salamander]]
|Northeastern North America ([[Ontario]] south to [[Virginia]] and west to [[Illinois]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Blue Spotted Salamander (Ambystoma laterale) (44133419344).jpg|200x200px]]
|''A. laterale''
[[Edward Hallowell (herpetologist)|Hallowell]], 1856
|[[Blue-spotted salamander]]
|Northeastern North America ([[Nova Scotia]] west to [[Manitoba]] and [[Minnesota]] and south to [[Indiana]] and [[New Jersey]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Abystoma leorae.jpg|200x200px]]
|''A. leorae''
[[Edward Harrison Taylor|Taylor]], 1943
|[[Leora's stream salamander]], Ajolote
|Central Mexico ([[State of Mexico|Mexico state]] - [[Puebla]] border), [[Mount Tlaloc]]
|Terrestrial
|[[File:Fl_mammals_cr.svg]]
|-
|
|''A. lermaense''
([[Edward Harrison Taylor|Taylor]], 1940)
|[[Lake Lerma salamander]]
|Central Mexico ([[State of Mexico]]), [[Lake Lerma]] near [[Toluca]]
|Terrestrial and neotenic
|[[File:Fl_mammals_en.svg]]
|-
|[[File:Ambystoma mabeei 243442264.jpg|200x200px]]
|''A. mabeei''
Bishop, 1928
|[[Mabee's salamander]]
|Coastal southeast United States (southeast [[Virginia]] to [[South Carolina]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Ambystoma macrodactylum macrodactylum 177970468.jpg|200x200px]]
|''A. macrodactylum''
[[Spencer Fullerton Baird|Baird]], 1950
|[[Long-toed salamander]]
|Northwest North America ([[Alaska]] south to northern [[California]] and east to [[Alberta]] and [[Montana]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Spotted Salamander (Ambystoma maculatum) (32855631122).jpg|200x200px]]
|''A. maculatum''
([[George Shaw (biologist)|Shaw]], 1802)
|[[Spotted salamander]]
|Eastern North America ([[Nova Scotia]] west to [[Wisconsin]] and south to eastern [[Texas]] and [[Georgia (U.S. state)|Georgia]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Ambystoma mavortium1.jpg|200x200px]]
|''A. mavortium''
[[Spencer Fullerton Baird|Baird]], 1850
|[[Barred tiger salamander]]
|Western North America ([[Manitoba]] south to [[Texas]] and west to [[Washington (state)|Washington]] and [[California]])
|Terrestrial and neotenic
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Ajolote 1.JPG|200x200px]]
|''A. mexicanum''
([[George Shaw (biologist)|Shaw]] and [[Frederick Polydore Nodder|Nodder]], 1798)
|[[Axolotl]]
|Central Mexico ([[State of Mexico]]), [[Lake Xochimilco]]
|Neotenic
|[[File:Fl_mammals_cr.svg]]
|-
|[[File:Marbled Salamander (Ambystoma opacum) (15401883638).jpg|200x200px]]
|''A. opacum''
([[Johann Ludwig Christian Gravenhorst|Gravenhorst]], 1807)
|[[Marbled salamander]]
|Eastern United States ([[New Hampshire]] south to northern [[Florida]] and east to [[Missouri]] and [[Texas]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|
|''A. ordinarium''
[[Edward Harrison Taylor|Taylor]], 1940
|[[Puerto Hondo stream salamander]]
|West-central Mexico ([[Michoacán|Michoacán state]]), Puerto Hondo stream
|Terrestrial and neotenic
|[[File:Fl_mammals_en.svg]]
|-
|[[File:Ambystoma rivulare.jpg|200x200px]]
|''A. rivulare''
[[Edward Harrison Taylor|Taylor]], 1940
|[[Michoacan stream salamander]]
|Central Mexico (western [[State of Mexico]])
|Terrestrial and neotenic
|[[File:Fl_mammals_en.svg]]
|-
|[[File:Ambystoma rosaceum 412366.jpg|200x200px]]
|''A. rosaceum''
[[Edward Harrison Taylor|Taylor]], 1941
|[[Tarahumara salamander]]
|Northwest Mexico, [[Sierra Madre Occidental]]
|Terrestrial and neotenic
|[[File:Fl_mammals_lc.svg]]
|-
|
|''A. silvense''
[[Robert G. Webb|Webb]], 2004
|[[Durango salamander]]
|Northwest Mexico ([[Durango]] and [[Chihuahua (state)|Chihuahua]]), [[Sierra Madre Occidental]]
|Terrestrial and neotenic
|[[File:Fl_mammals_dd.svg]]
|-
|[[File:Mole Salamander (Ambystoma talpoideum) (39994300015).jpg|200x200px]]
|''A. talpoideum''
[[John Edwards Holbrook|Holbrook]], 1838
|[[Ambystoma talpoideum|Mole salamander]]
|Southeast United States ([[Virginia]] west to [[Oklahoma]] and south to northern [[Florida]])
|Terrestrial and neotenic
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Ambystoma taylori.jpeg|200x200px]]
|''A. taylori''
[[Ronald A. Brandon|Brandon]], Maruska, and Rumph, 1982
|[[Taylor's salamander]]
|Southeast Mexico ([[Puebla]]), [[Laguna Alchichica]]
|Neotenic
|[[File:Fl_mammals_cr.svg]]
|-
|[[File:Smallmouth Salamander (Ambystoma texanum) (46619065801).jpg|200x200px]]
|''A. texanum''
Matthes, 1855
|[[Small-mouth salamander]]
|South-central United States ([[Ohio]] west to [[Nebraska]] and south to [[Texas]] and [[Alabama]])
|Terrestrial
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Eastern Tiger Salamander (Ambystoma tigrinum) (25522389762).jpg|200x200px]]
|''A. tigrinum''
([[Jacob Green (naturalist)|Green]], 1825)
|[[Eastern Tiger Salamander|Eastern tiger salamander]]
|Eastern North America ([[New York (state)|New York]] northwest to [[Manitoba]] and south to [[Texas]] and northern [[Florida]])
|Terrestrial and neotenic
|[[File:Fl_mammals_lc.svg]]
|-
|[[File:Ambystoma velasci.jpg|200x200px]]
|''A. velasci''
([[Alfredo Dugès|Dugès]], 1888)
|[[Plateau tiger salamander]]
|[[Mexican Plateau]]
|Terrestrial and neotenic
|[[File:Fl_mammals_lc.svg]]
|}
In addition, two groups of unisexual hybrid populations are sometimes named under their own species:
* [[Silvery salamander]] (''A. platineum'')
* [[Tremblay's salamander]] (''A. tremblayi'')
==See also==
Line 93 ⟶ 332:
==External links==
{{Wikispecies-inline|Ambystomatidae}}
{{
*[http://tolweb.org/Ambystomatidae/15448 Tree of Life: Ambystomatidae]
*[https://web.archive.org/web/20050529085120/http://www.herpseeker.com/worldspecies/Caudata/ambystomatidae/ambystoma.htm Herpseeker.dk]
Line 100 ⟶ 339:
{{Caudata}}
{{Taxonbar|from=Q2513619}}
{{Authority control}}
[[Category:Salamandroidea]]
| |||
Latest revision as of 11:12, 10 June 2024
 | This article needs additional citations for verification. (October 2008) |
| Mole salamanders | |
|---|---|
| |
| Spotted salamander (Ambystoma maculatum) | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Amphibia |
| Order: | Urodela |
| Family: | Ambystomatidae |
| Genus: | Ambystoma Tschudi, 1838 |
The mole salamanders (genus Ambystoma) are a group of advanced salamanders endemic to North America. The group has become famous due to the presence of the axolotl (A. mexicanum), widely used in research due to its paedomorphosis, and the tiger salamander (A. tigrinum, A. mavortium) which is the official amphibian of many US states, and often sold as a pet.
General description
[edit]
Terrestrial mole salamanders are identified by having wide, protruding eyes, prominent costal grooves, and thick arms. Most have vivid patterning on dark backgrounds, with marks ranging from deep blue spots to large yellow bars depending on the species. Terrestrial adults spend most of their lives underground in burrows, either of their own making or abandoned by other animals. Some northern species may hibernate in these burrows throughout the winter. They live alone and feed on any available invertebrate. Adults spend little time in the water, only returning to the ponds of their birth to breed.
All mole salamanders are oviparous and lay large eggs in clumps in the water. Their fully aquatic larvae are branchiate, with three pairs of external gills behind their heads and above their gill slits. Larvae have large caudal fins, which extend from the back of their heads to their tails and to their cloacae. Larvae grow limbs soon after hatching, with four toes on the fore arms, and five toes on the hind legs. Their eyes are wide-set and lack true eyelids.
The larvae of some species (especially those in the south, and tiger salamanders) can reach their adult size before undergoing metamorphosis. During metamorphosis, the gills of the larvae disappear, as do the fins. Their tails, skin, and limbs become thicker, and the eyes develop lids. Their lungs become fully developed, allowing for a fully terrestrial existence.
Some species of mole salamanders (as well as populations of normally terrestrial species) are neotenic (retaining their larval form into adulthood). The most famous example is the axolotl. They cannot produce thyroxine, so their only means of metamorphosis is mainly through the outside injection of it. This usually shortens the lifespan of the salamander.
Tiger salamander complex
[edit] |
The presence of neotenic populations near those with large larvae has made it difficult to identify mole salamander species. The tiger salamander complex was previously considered a single species ranging from Canada to Mexico, falling under the name A. tigrinum. Despite differences in coloration and larvae, tiger salamanders were found throughout their unbroken range, which made it difficult to delineate subspecies, let alone elevate any populations to species status. In morphological terms, tiger salamanders are all very similar, with large heads, small eyes, and thick bodies. This is probably because tiger salamanders have the primitive morphology of mole salamanders. They are also the largest of the mole salamanders, and have very large larvae. All populations have similar lifestyles, and their lifecycles are identical. However, when one looks at tiger salamander populations distant from each other, different species within this complex become apparent. The ranges of these potential species overlap, and hybridization occurs, blurring the lines between species.
Several subspecies of A. tigrinum were named to deal with this problem. Recently, the barred tiger salamander (A. mavortium) was elevated to species status—covering the tiger salamander populations in the western and central United States. Several distinct subspecies still exist in A. mavortium, which may be elevated to species status at some point in the future. The California tiger salamander (A. californiense) has also been elevated out of A. tigrinum, and is actually very distantly related to all other mole salamander species. The Plateau tiger salamander (A. velasci) was elevated out of A. tigrinum through genetic analysis in 1997. All accounts referring to the axolotl (A. mexicanum) as a close relative of A. tigrinum are now considered wrong, as they are now separated by both geography and many species between. Instead, it is A. velasci, which shares the axolotl's habitat, and is probably closely related to it. The Plateau tiger salamander was probably the parent of most of the neotenic species, which raises the possibility that A. velasci is paraphyletic, and may be broken up into more species in the future.
Hybrid all-female populations
[edit] | It has been suggested that this article should be split into a new article titled Unisexual salamander. (discuss) (April 2024) |
Unisexual (all-female) populations of ambystomatid salamanders are widely distributed across the Great Lakes region and northeastern North America. The females require sperm from a co‑occurring, related species to fertilize their eggs and initiate development. Usually[1] the eggs then discard the sperm genome and develop asexually (i.e., gynogenesis, with premeiotic doubling); however, they may incorporate the genome from the sperm into the resulting offspring.[2] Sperm incorporation commonly[1] takes the form of genome addition (resulting in ploidy elevation in the offspring), or genome replacement, wherein one of the maternal genomes is discarded. This unique mode of reproduction has been termed kleptogenesis by Bogart and colleagues.[2] This is in contrast to hybridogenesis, where the maternal genomes are passed hemiclonally and the paternal genome is discarded every generation before the egg matures and reacquired from the sperm of another species.
The nuclear DNA of the unisexuals generally comprises genomes from up to five species:[3] the blue-spotted salamander (A. laterale), Jefferson salamander (A. jeffersonianum), small-mouthed salamander (A. texanum), streamside salamander (A. barbouri), and tiger salamander (A. tigrinum), denoted respectively as L, J, Tx, B, and Ti. This flexibility results in a large number of possible nuclear biotypes (genome combinations) in the unisexuals. For example, an LJJ individual would be a triploid with one A. laterale genome and two A. jeffersonianum genomes, while an LTxJTi individual would be a tetraploid with genomes from four species. Because they have hybrid genomes, unisexual salamanders are a cryptic species with morphology similar to coexisting species. For example, LLJs look like blue-spotted salamanders and LJJs look like Jefferson salamanders. Silvery salamanders LJJ (A. platineum), Tremblay's salamanders LLJ (A. tremblayi), and Kelly's Island salamanders LTxTx and LTxTi (A. nothagenes) were initially described as species. Species names were later dropped for all unisexual salamanders because of the complexity of their genomes. The offspring of a single mother may have different genome complements;[2] for example, a single egg mass may have both LLJJ and LJJ larvae.
Despite the complexity of the nuclear genome, all unisexuals form a monophyletic group based on their mitochondrial DNA. The maternal ancestor of the unisexual ambystomatids was most closely related to the streamside salamander, with the original hybridization likely occurring 2.4~3.9 million years ago,[2] making it the oldest known lineage of all-female vertebrates.[4] The hybridization was most probably with an A. laterale. All known unisexuals have at least one A. laterale genome[3] and this is thought to be essential for unisexuality. However, the A. laterale genome has been replaced several times, independently, in each of the lineages by matings with A. laterale.
Limb regeneration
[edit]Ambystoma mexicanum, a neotenic salamander with exceptional regenerative capabilities is one of the principal models for studying limb regeneration.[5] Limb regeneration involves the propagation of a mass of low differentiated and highly proliferative cells termed the blastema.[5][6] During limb regeneration, blastema cells experience DNA double-strand breaks and thus require homologous recombination, a form of DNA repair that deals with double-strand breaks.[6]
Taxonomy
[edit]
Rhyacosiredon was previously considered a separate genus within the family Ambystomatidae. However, cladistic analysis of the mole salamanders found the existence of Rhyacosiredon makes Ambystoma paraphyletic, since the species are more closely related to some Ambystoma species than those species are to others in Ambystoma. The stream-type morphology of these salamanders (which includes larvae and neotenes with short gills and thicker gular folds) may have led to their misclassification as a different genus.
The genus name Ambystoma was given by Johann Jakob von Tschudi in 1839,[7] and is traditionally translated as "cup-mouth",[citation needed]. Tschudi did not provide a derivation for the name, and many thought that he intended the name Amblystoma, "blunt-mouth." Occasionally, old specimens and documents use the name Amblystoma. Writing in 1907, Leonhard Stejneger offered a derivation of Ambystoma based on the contraction of a Greek phrase meaning "to cram into the mouth,"[8][9] but others have not found this explanation convincing.[10] In the absence of clear evidence that Tschudi committed a lapsus, the name given in 1839 stands.
Species
[edit]This genus contains 32 species, listed below, the newest being A. bishopi. Some Ambystoma species are Terrestrial, others are neotenic, and some species have established populations of both neotenic and terrestrial forms.
| Image | Species and author | Common name | Distribution | Lifestyle | IUCN status |
|---|---|---|---|---|---|
|
A. altamirani
Dugès, 1895 |
Mountain stream salamander, Achoque | Central Mexico, west and south of the Valley of Mexico | Terrestrial and neotenic | 
|
| A. amblycephalum
Taylor, 1940 |
Blunt-headed salamander | West-central Mexico (Michoacán state), near Morelia | Terrestrial and neotenic | 
| |
|
A. andersoni | Anderson's salamander | West-central Mexico (Michoacán state), Laguna de Zacapu | Neotenic |
|
|
A. annulatum
Cope, 1886 |
Ringed salamander | South-central United States (Arkansas, Illinois, Missouri, Oklahoma), Ozark Plateau and Ouachita Mountains | Terrestrial | 
|
|
A. barbouri
Kraus & Petranka, 1989 |
Streamside salamander | South-midwest United States (Indiana, Kentucky, Ohio, Tennessee, West Virginia) | Terrestrial | 
|
| A. bishopi | Reticulated flatwoods salamander | Southeast United States (Florida Panhandle and southernmost Georgia), west of the Apalachicola-Flint River | Terrestrial | 
| |
| A. bombypellum
(Taylor, 1940) |
Delicate-skinned salamander | Central Mexico (State of Mexico) near Jilotepec | Terrestrial | 
| |
|
A. californiense
Gray, 1853 |
California tiger salamander | Central Valley of California | Terrestrial |
|
|
A. cingulatum
Cope, 1868 |
Frosted flatwoods salamander | Southeast United States (southern South Carolina and Georgia south to northern Florida) | Terrestrial |
|
|
A. dumerilii
(Dugès, 1870) |
Lake Pátzcuaro salamander, Achoque | West-central Mexico (Michoacán state), Lake Pátzcuaro | Neotenic |
|
|
A. flavipiperatum
Dixon, 1963 |
Yellow-peppered salamander, Ajolote de Chapala | West-central Mexico (Jalisco) | Terrestrial |
|
|
A. gracile
(Baird, 1859) |
Northwestern salamander | Northwest North America (southernmost Alaska to northern California) | Terrestrial |
|
| A. granulosum
Taylor, 1944 |
Granular salamander, Ajolote | Central Mexico (State of Mexico) near Toluca | Terrestrial |
| |
|
A. jeffersonianum
(Green, 1827) |
Jefferson salamander | Northeastern North America (Ontario south to Virginia and west to Illinois) | Terrestrial |
|
|
A. laterale
Hallowell, 1856 |
Blue-spotted salamander | Northeastern North America (Nova Scotia west to Manitoba and Minnesota and south to Indiana and New Jersey) | Terrestrial |
|
|
A. leorae
Taylor, 1943 |
Leora's stream salamander, Ajolote | Central Mexico (Mexico state - Puebla border), Mount Tlaloc | Terrestrial |
|
| A. lermaense
(Taylor, 1940) |
Lake Lerma salamander | Central Mexico (State of Mexico), Lake Lerma near Toluca | Terrestrial and neotenic |
| |
|
A. mabeei
Bishop, 1928 |
Mabee's salamander | Coastal southeast United States (southeast Virginia to South Carolina) | Terrestrial |
|
|
A. macrodactylum
Baird, 1950 |
Long-toed salamander | Northwest North America (Alaska south to northern California and east to Alberta and Montana) | Terrestrial |
|
|
A. maculatum
(Shaw, 1802) |
Spotted salamander | Eastern North America (Nova Scotia west to Wisconsin and south to eastern Texas and Georgia) | Terrestrial |
|
|
A. mavortium
Baird, 1850 |
Barred tiger salamander | Western North America (Manitoba south to Texas and west to Washington and California) | Terrestrial and neotenic |
|
|
A. mexicanum | Axolotl | Central Mexico (State of Mexico), Lake Xochimilco | Neotenic |
|
|
A. opacum
(Gravenhorst, 1807) |
Marbled salamander | Eastern United States (New Hampshire south to northern Florida and east to Missouri and Texas) | Terrestrial |
|
| A. ordinarium
Taylor, 1940 |
Puerto Hondo stream salamander | West-central Mexico (Michoacán state), Puerto Hondo stream | Terrestrial and neotenic |
| |
|
A. rivulare
Taylor, 1940 |
Michoacan stream salamander | Central Mexico (western State of Mexico) | Terrestrial and neotenic |
|
|
A. rosaceum
Taylor, 1941 |
Tarahumara salamander | Northwest Mexico, Sierra Madre Occidental | Terrestrial and neotenic |
|
| A. silvense
Webb, 2004 |
Durango salamander | Northwest Mexico (Durango and Chihuahua), Sierra Madre Occidental | Terrestrial and neotenic |
| |
|
A. talpoideum
Holbrook, 1838 |
Mole salamander | Southeast United States (Virginia west to Oklahoma and south to northern Florida) | Terrestrial and neotenic |
|
|
A. taylori
Brandon, Maruska, and Rumph, 1982 |
Taylor's salamander | Southeast Mexico (Puebla), Laguna Alchichica | Neotenic |
|
|
A. texanum
Matthes, 1855 |
Small-mouth salamander | South-central United States (Ohio west to Nebraska and south to Texas and Alabama) | Terrestrial |
|
|
A. tigrinum
(Green, 1825) |
Eastern tiger salamander | Eastern North America (New York northwest to Manitoba and south to Texas and northern Florida) | Terrestrial and neotenic |
|
|
A. velasci
(Dugès, 1888) |
Plateau tiger salamander | Mexican Plateau | Terrestrial and neotenic |
|
In addition, two groups of unisexual hybrid populations are sometimes named under their own species:
- Silvery salamander (A. platineum)
- Tremblay's salamander (A. tremblayi)
See also
[edit]References
[edit]- ^ a b Bi, Ke; Bogart, James P.; Fu, Jinzhong (2008). "The prevalence of genome replacement in unisexual salamanders of the genus Ambystoma (Amphibia, Caudata) revealed by nuclear gene genealogy". BMC Evolutionary Biology. 8 (1): 158. Bibcode:2008BMCEE...8..158B. doi:10.1186/1471-2148-8-158. ISSN 1471-2148. PMC 2413238. PMID 18498635.
- ^ a b c d Bogart, James P.; Bi, Ke; Jinzong Fu; Noble, Daniel W.A.; Niedzwiecki, John (February 2007). "Unisexual salamanders (genus Ambystoma) present a new reproductive mode for eukaryotes". Genome. 50 (2): 119–136. doi:10.1139/g06-152. ISSN 0831-2796. PMID 17546077.
- ^ a b Bogart, J.P.; Bartoszek, J.; Noble, D.W.A.; Bi, K. (29 July 2009). "Sex in unisexual salamanders: discovery of a new sperm donor with ancient affinities". Heredity. 103 (6): 483–493. doi:10.1038/hdy.2009.83. ISSN 0018-067X. PMID 19639004.
- ^ Bi, Ke; Bogart, James P. (2010). "Time and time again: Unisexual salamanders (genus Ambystoma) are the oldest unisexual vertebrates". BMC Evolutionary Biology. 10 (1): 238. Bibcode:2010BMCEE..10..238B. doi:10.1186/1471-2148-10-238. ISSN 1471-2148. PMC 3020632. PMID 20682056.
- ^ a b García-Lepe UO, Cruz-Ramírez A, Bermúdez-Cruz RM. DNA repair during regeneration in Ambystoma mexicanum. Dev Dyn. 2021 Jun;250(6):788-799. doi: 10.1002/dvdy.276. Epub 2020 Dec 17. PMID 33295131
- ^ a b García-Lepe UO, Torres-Dimas E, Espinal-Centeno A, Cruz-Ramírez A, Bermúdez-Cruz RM. Evidence of requirement for homologous-mediated DNA repair during Ambystoma mexicanum limb regeneration. Dev Dyn. 2022 Jun;251(6):1035-1053. doi: 10.1002/dvdy.455. Epub 2022 Jan 25. PMID 35040539
- ^ Tschudi, Johann Jakob (1839). "Classification der Batrachier, mit Berucksichtigung der Fossilen Thiere dieser Abtheilung der Reptilien". Mémoires de la Société des Sciences Naturelles de Neuchatel. 2 (4): 57, 92.
- ^ Stejneger, Leonhard (1907). "Herpetology of Japan and Adjacent Territory". Bulletin of the United States National Museum. 58: 24. hdl:2027/mdp.39015006820313.
- ^ Lyon Jr., M. W. (30 June 1916). "Ambystoma not Amblystoma". Science. 43 (1122): 929–930. doi:10.1126/science.43.1122.929-a. JSTOR 1639383. PMID 17793100.
- ^ Scott, Charles P. G. (1 September 1916). "Amblystoma not Ambystoma". Science. 44 (1131): 309–311. doi:10.1126/science.44.1131.309-a. JSTOR 1642899. PMID 17840073. S2CID 5490505.
External links
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Caudate families by suborder | ||
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| Cryptobranchoidea |  | |
| Salamandroidea | ||
| Sirenoidea | ||
