The Pacific giant salamanders (frequently stylized as Giant Pacific Salamanders or GPS) are members of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Dicamptodon''. They are large

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

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. Tho ...

in North America. They are included in the family

Ambystomatidae Ambystomatidae is a family of salamanders belonging to the order Caudata in the class Amphibia. It contains two genera, ''Ambystoma'' (the mole salamanders) and ''Dicamptodon'' (the Pacific giant salamanders). ''Ambystoma'' contains 32 species a ...

, or alternatively, in their own monogeneric family Dicamptodontidae.

Description

Dicamptodon and its urine imaged with blue excitation light and a yellow long pass filter - 41598 2020 59528 Supp Fig3

Pacific giant salamanders are defined by their wide protruding eyes, costal grooves, thick arms, and dark background coloring. ''Dicamptodon'' have a snout-vent-length (SVL) of 350 mm, a broad head, laterally flexible flattened tails, paired premaxillae that are separate from the nasals, and the aquatic larvae have gills. ''Dicamptodon'' have lacrimals and pterygoids that are present, but quadratojugal are absent. While most salamanders are silent, the Pacific giant salamander is one of several salamanders that have vocal abilities. When startled, these salamanders may respond with a croaky-sounding cry similar to that of a barking dog.

Habitat

Pacific giant salamanders are semi-aquatic animals that occupy both aquatic and terrestrial habitats. They are commonly found in various lotic environments in altitudes ranging from 0 to 7000 feet above sea level in the Pacific Northwest and Northern California. Aquatic salamander abundance has been shown to increase with increasing rock coverage, and decrease with increasing water velocity, and tend to prefer cold mountain streams and lakes. Pacific giant salamanders also utilize terrestrial refuge sites such as decaying wood, burrows, or under rocks.

Taxonomy

The

''Dicamptodon'' was formerly thought to contain two species,

Cope's giant salamander Cope's giant salamander (''Dicamptodon copei'') is a species of salamander in the family Dicamptodontidae, the Pacific giant salamanders.Behler, J. L. and F. W. King. (1979) ''National Audubon Society Field Guide to Reptiles and Amphibians'', Kn ...

(''D. copei'') on the

Olympic Peninsula The Olympic Peninsula is a large arm of land in western Washington that lies across Puget Sound from Seattle, and contains Olympic National Park. It is bounded on the west by the Pacific Ocean, the north by the Strait of Juan de Fuca, and th ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

, and the Pacific giant salamander (''D. ensatus'') which consisted of three geographic populations, an

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

isolate, a group in northern

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, and a group in

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...

and Washington. In 1989, genetic studies showed ''D. copei'' to be a distinct species, and the ''D. ensatus'' populations to consist of three species: the

Idaho giant salamander The Idaho giant salamander, ''Dicamptodon aterrimus'', is a species of salamander. There are three closely related species to this taxon: ''D. ensatus'', (California giant salamander), ''D. copei'' (Cope's giant salamander) and ''D. tenebrosus'' ...

(''D. aterrimus'') in Idaho, and two highly divergent species with a narrow hybrid zone in California, the coastal giant salamander (''D. tenebrosus'') (ranging from northern California to Washington), and the California giant salamander (''D. ensatus'') (limited only from Santa Cruz County to

Mendocino County Mendocino County (; ''Mendocino'', Spanish for "of Mendoza) is a county located on the North Coast of the U.S. state of California. As of the 2020 census, the population was 91,601. The county seat is Ukiah. Mendocino County consists whol ...

in California). The earliest known member of this genus and family is '' D. antiquus'' from the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

Extant species

There are four extant ''Dicamptodon'' species.

References

External links

Dicamptodon
at CalPhotos {{Taxonbar, from1=Q14547873, from2=Q905053 * Amphibian genera Extant Thanetian first appearances Taxa named by Alexander Strauch