Ambystomatidae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of salamanders belonging to the order Caudata in the class

Amphibia Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbo ...

. It contains two genera, ''Ambystoma'' (the

mole salamander 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, an ...

s) and ''Dicamptodon'' (the

Pacific giant salamander The Pacific giant salamanders (frequently stylized as Giant Pacific Salamanders or GPS) are members of the genus ''Dicamptodon''. They are large salamanders endemic to the Pacific Northwest in North America. They are included in the family Ambyst ...

s). ''Ambystoma'' contains 32 species and are distributed widely across North America, while ''Dicamptodon'' contains four species restricted to the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Thou ...

. These salamanders are mostly terrestrial and eat invertebrates, although some species are known to eat smaller salamanders. They can be found throughout the US and some areas of Canada in damp forests or plains. This family contains some of the largest terrestrial salamanders in the world, the tiger salamander and the

coastal giant salamander The coastal giant salamander (''Dicamptodon tenebrosus'') is a species of salamander in the family Dicamptodontidae (Pacific giant salamanders). It is endemic to the Pacific Northwest of North America. There are three closely related species to ...

. Some species are toxic and can secrete poison from their bodies as protection against predators or infraspecific competition.

Neoteny Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compare ...

has been observed in several species in Ambystomatidae, and some of them like the

axolotl The axolotl (; from nci, āxōlōtl ), ''Ambystoma mexicanum'', is a paedomorphic salamander closely related to the tiger salamander. Axolotls are unusual among amphibians in that they reach adulthood without undergoing metamorphosis. I ...

live all of their lives under water in their larval stage.

Characteristics and Behavior

Ambystomatids have chunky bodies with broad, flat heads and short legs. Tails are long and flattened. Colors range from black, brown, or a dull grey and can have brightly colored speckles or spots. Their skin is smooth and shiny. Most adults lack gills/gill slits and moveable eyes. There are no nasolabial grooves on the snout. Lungs are well-developed and functional. They have 10 costal grooves. Adult males have 6 sets of cloacal glands. Adult females have spermathecae in cloaca. Ambystomatids are nocturnal. Although they are more active at night, they may be found on cool days under moist leaf litter, logs, or rocks near water bodies. Adults tend to live in burrows and only return to waterbodies or streams to breed in early Spring. Fertilization is internal. Courtship occurs in water; males "dance," nudging the females then deposit numerous spermatophores. Most species have a larval period that extends for 3-4 months. Ambystomatids can be found in temperate forests and wetlands.

Taxonomy

The genus ''Rhyacotriton'' was formerly included in this family, but is now usually placed into its own family

Rhyacotritonidae The torrent salamanders or Cascade salamanders are a family of salamanders (Rhyacotritonidae) with only one genus, ''Rhyacotriton''. The torrent salamanders are endemic to the United States in the Pacific Northwest (including northwestern Calif ...

. In 2006, a large study of amphibian systematics (Frost et al., Bulletin of the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 int ...

, 297 (2006) placed ''Dicamptodon'' back within Ambystomatidae, based on

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis. This has been accepted by the Center for Indian Herpetology.

References

*http://amphibiaweb.org/lists/Ambystomatidae.shtml *http://tolweb.org/Ambystomatidae/15448

External links

Tree of Life: Ambystomatidae
Salamanders Amphibian families {{salamander-stub