Ambystoma és un gènere d'amfibis caudats representats per una gran nombre d'espècies.
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.
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.
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.
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.
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,[5] and is traditionally translated as "cup-mouth",. 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,"[6][7] but others have not found this explanation convincing.[8] In the absence of clear evidence that Tschudi committed a lapsus, the name given in 1839 stands.
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.
In addition, two groups of unisexual hybrid populations are sometimes named under their own species:
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.
Ambystoma es un género de anfibios caudados de la familia Ambystomatidae representados por un gran número de especies. Se distribuyen en Norteamérica. Algunas especies son neoténicas; no tienen metamorfosis y se reproducen en estadio juvenil. En algunas todos o solo ciertos individuos son neoténicos. Pueden reproducirse por partenogénesis.
La especie mejor conocida y usada en estudios de laboratorio es el ajolote mexicano, Ambystoma mexicanum.
Se reconocen las siguientes según ASW:[1]
Ambystoma es un género de anfibios caudados de la familia Ambystomatidae representados por un gran número de especies. Se distribuyen en Norteamérica. Algunas especies son neoténicas; no tienen metamorfosis y se reproducen en estadio juvenil. En algunas todos o solo ciertos individuos son neoténicos. Pueden reproducirse por partenogénesis.
La especie mejor conocida y usada en estudios de laboratorio es el ajolote mexicano, Ambystoma mexicanum.
Ambystoma anfibio genero bat da, Caudata ordenaren barruko Ambystomatidae familian sailkatua.
Ambystoma anfibio genero bat da, Caudata ordenaren barruko Ambystomatidae familian sailkatua.
Ambystoma on aksolotlien heimoon kuuluva sammakkoeläinsuku. Siihen kuuluu 33 lajia. Joillakin lajeilla muodonmuutos tapahtuu normaalisti, mutta joillakin se jää vajavaiseksi, kuten aksolotlilla.
Suvun lajit ovat yleensä kookkaita. Suurimpia ovat kookkaimmat tiikerisalamanterit, jotka ovat 34 sentin pituisia.
Suvun lajeja tavataan eteläisestä Kanadasta Meksikoon saakka.[2]
Sukuun kuuluu 33 lajia:[3][4][5][6]
Ambystoma on aksolotlien heimoon kuuluva sammakkoeläinsuku. Siihen kuuluu 33 lajia. Joillakin lajeilla muodonmuutos tapahtuu normaalisti, mutta joillakin se jää vajavaiseksi, kuten aksolotlilla.
Ambystoma est un genre d'urodèles de la famille des Ambystomatidae[1].
Les 33 espèces de ce genre se rencontrent en Amérique du Nord[1].
Ces espèces pratiquent la gynogenèse.
Selon Amphibian Species of the World (17 février 2014)[2] :
Ambystoma est un genre d'urodèles de la famille des Ambystomatidae.
Ambystoma Tschudi, 1838 è un genere di anfibi caudati endemico del Nord America.[1]
Il genere comprende le seguenti specie:[1]
Ambystoma Tschudi, 1838 è un genere di anfibi caudati endemico del Nord America.
Ambystoma is een geslacht van salamanders uit de familie molsalamanders (Ambystomatidae).
De salamanders worden wel aangeduid met molsalamanders, net als de familie waartoe ze behoren. De groep werd voor het eerst wetenschappelijke beschreven door Johann Jakob von Tschudi in 1838. Oorspronkelijk werd de naam Axolotus gebruikt, ook is de groep beschreven onder namen Philhydrus en Siredon.[1] De wetenschappelijke naam Ambystoma betekent vrij vertaald 'afgeronde mond' en is afgeleid van de Oudgriekse woorden ἀμβλύς, amblus (stomp) en στόμα, stoma (opening).
De verschillende soorten worden ongeveer tien tot dertig centimeter lang en hebben een donkere lichaamskleur met lichtere vlekken of strepen. Het lichaam is vaak worstvormig, met een dorsaal afgeplatte kop en een zijdelings afgeplatte staart.[2]
Alle soorten zijn terrestrisch en leven op de bodem. De larven kunnen zich soms ontwikkelen tot volwassen exemplaren zonder een echte gedaanteverwisseling of metamorfose. De bekendste soort is de axolotl (Ambystoma mexicanum), die meestal in de larvale vorm blijft.
Er zijn 33 soorten die voorkomen in Noord-Amerika: Canada, de Verenigde Staten en Mexico.[2] Alle soorten groeien op in het water maar leven eenmaal volwassen op het land.
Sommige soorten werden lange tijd als ondersoort beschouwd van andere soorten. Voorbeelden zijn de soorten geelgeblokte tijgersalamander (Ambystoma mavortium) en de Mexicaanse tijgersalamander (Ambystoma velasci), die lange tijd gezien werden als ondersoorten van de tijgersalamander (Ambystoma tigrinum)
Geslacht Ambystoma
Ambystoma is een geslacht van salamanders uit de familie molsalamanders (Ambystomatidae).
Multimedia w Wikimedia Commons Ambystoma – rodzaj płaza ogoniastego z rodziny ambystomowatych (Ambystomatidae).
Rodzaj obejmuje gatunki występujące od Labradoru, Zatoki Jamesa i ekstremalnie południowo-wschodniej Alaski, na południa przez południową Kanadę, większość Stanów Zjednoczonych i Sierra Madre Zachodnia oraz centralny płaskowyż Meksyku; najwyraźniej nieobecne na półwyspie Floryda, również w Nevadzie, południowej Kalifornii, południowo-zachodniej Arizonie (Stany Zjednoczone), Kalifornii Dolnej i tropikalnych nizinach Meksyku[31].
Niektóre gatunki, jak ambystoma meksykańska (Ambystoma mexicanum) posiadają zdolność rozmnażania się już w postaci larwalnej. Zjawisko to znane jest pod nazwą neotenii, a neoteniczna postać larwalna płazów z tego rodzaju nazywana jest aksolotlem.
Ambystoma tigrinum i A. mavortium w postaci larwalnej są bardzo podobne do A. mexicanum i zapewne dlatego z nim mylone. Larwy A. tigrinum i A. movortium znane są jako "water dog".
Do rodzaju należą następujące gatunki[31]:
Ambystoma – rodzaj płaza ogoniastego z rodziny ambystomowatych (Ambystomatidae).
Ambystoma[2] är ett släkte av groddjur som ingår i familjen mullvadssalamandrar.[2]
Arterna förekommer i Kanada, USA och i bergstrakter samt på högplatå i Mexiko.[1]
Denna groddjurs-relaterade artikel saknar väsentlig information. Du kan hjälpa till genom att tillföra sådan.
Ambystoma är ett släkte av groddjur som ingår i familjen mullvadssalamandrar.
Arterna förekommer i Kanada, USA och i bergstrakter samt på högplatå i Mexiko.
Ambystoma là một họ động vật lưỡng cư trong bộ Caudata. Họ này có 31-32 loài, trong đó 45% bị đe dọa hoặc tuyệt chủng.[1][2]
Theo Darrel Frost và The American Museum of Natural History, họ này có 2 chi là Ambystoma và Dicamptodon[3]
Theo AmphibiaWeb: Information on amphibian biology and conservation, họ Ambystomatidae gồm các 1 chi và 32 loài, riêng chi Dicamptodon được tách thành 1 chi duy nhất trong họ Dicamptodontidae với 4 loài:
Phương tiện liên quan tới Ambystoma tại Wikimedia Commons
Bài viết Bộ Có đuôi này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Ambystoma là một họ động vật lưỡng cư trong bộ Caudata. Họ này có 31-32 loài, trong đó 45% bị đe dọa hoặc tuyệt chủng.
Амбистомы[1] (лат. Ambystoma) — род земноводных из семейства амбистомовых. Содержит 32 вида. Эндемики Северной Америки. Предпочитают влажные местообитания. Ведут скрытный образ жизни, прячась в норы, под камни. Питаются червями и другими мелкими беспозвоночными.
Это заготовка статьи по герпетологии. Вы можете помочь проекту, дополнив её. Амбистомы (лат. Ambystoma) — род земноводных из семейства амбистомовых. Содержит 32 вида. Эндемики Северной Америки. Предпочитают влажные местообитания. Ведут скрытный образ жизни, прячась в норы, под камни. Питаются червями и другими мелкими беспозвоночными.
鈍口螈屬（學名：Ambystoma）是多種分布於北美的蠑螈。體型中等。有明顯的肋骨間溝。尾部側向壓縮。頭部寬大、眼小。不好動。通常棲息於地底。由於棲息地的破壞，多個物種均為瀕危物種。
約33種：
점박이도롱뇽속(Ambystoma)은 북아메리카에 사는 도롱뇽 분류군으로 점박이도롱뇽과(Ambystomatidae)의 유일속이다.
2012년 현재, 도룡뇽목의 계통 분류는 다음과 같다.[1]
양서류 도롱뇽목 도롱뇽아목 사이렌아목 영원아목
Wikispecies har information om 
