Ensatina | |
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Monterey Ensatina (Ensatina eschscholtzii eschscholtzii) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Urodela |
Family: | Plethodontidae |
Subfamily: | Plethodontinae |
Genus: | Ensatina Gray, 1850 |
Species: | E. eschscholtzii |
Binomial name | |
Ensatina eschscholtzii Gray, 1850 | |
Synonyms | |
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The ensatina (Ensatina eschscholtzii) is a species complex of plethodontid (lungless) salamanders [2] found in coniferous forests, oak woodland and chaparral [3] from British Columbia, through Washington, Oregon, across California (where all seven subspecies variations are located), all the way down to Baja California in Mexico. The genus Ensatina originated approximately 21.5 million years ago. [4] It is usually considered as monospecific, being represented by a single species, Ensatina eschscholtzii, with several subspecies forming a ring species.
The ensatina subspecies E. eschscholtzii eschscholtzii, or Monterey ensatina, can be found in Santa Cruz, Monterey, and the California coastal mountains. It reaches a total length (including tail) of 3–5 in (7.6–12.7 cm), and can be identified primarily by the structure of the tail, and how it is narrower at the base. This salamander is the only subspecies that has this tail structure and five toes on the back feet.
Males often have longer tails than the females, and many of the salamanders have lighter colored limbs in comparison to the rest of the body. The adult female lays eggs underground, often in threes, which then hatch directly into salamanders, skipping the usual aquatic phase.
The ensatina subspecies Ensatina eschscholtzii klauberi, or large blotched ensatina, can be found along the mountain ranges in Southern California, as well as a small region in Sierra Juarez, a mountain range located in northern Baja California.
E. e. klauberi is similar in size to E. e. eschscholtzii; it is mid-sized with adults having a total length of 3–6 in (7.6–15.2 cm). Females tend to have shorter and wider bodies compared to their male counterparts. This subspecies differs from E. e. eschscholtzii in its coloration. It is nearly black in color with blotches of orange that are present from head to tail, and it has dark eyes. [5]
Ensatina eschscholtzii has been described as a ring species in the mountains surrounding the Californian Central Valley. [2] The complex forms a horseshoe shape around the mountains, and though interbreeding can happen between each of the 19 populations around the horseshoe, the Ensatina eschscholtzii subspecies on the western end of the horseshoe cannot interbreed with the Ensatina klauberi on the eastern end. [6] As such, it is thought to be an example of incipient speciation, and provides an illustration of "nearly all stages in a speciation process" (Dobzhansky, 1958). [2] [7] Richard Highton argued that Ensatina is a case of multiple species and not a continuum of one species (meaning, by traditional definitions, it is not a ring species). [8]
They are generally thought to be found in high elevations, from 520 to 2400m, in conifer forests and oak woodlands. However, populations were discovered along the coast in Volcán Riveroll, a volcanic area located in Baja California. It is thought that they are able to survive in this anomalous region due to the high moisture that comes in from the coast. It is unclear how these populations were able to end up in this coastal region, but it is hypothesized that “the subspecies was once more broadly distributed and became isolated as a result of climate change during the late Pleistocene and Holocene.” [9] If this is true, then it is estimated that Ensatina klauberi has been living in this region for thousands of years.
Ensatina can usually be found under logs or brush, by or in streams and lakes, and in other moist places. They are easily distressed by improper handling, because they rely on cutaneous respiration, their thin skin is very sensitive to heating, drying and exposure to chemicals from warm hands. They may exude a sticky milky secretion from the tail. [10]
Plethodon is a genus of salamanders in the family Plethodontidae. They are commonly known as woodland salamanders. All members of the genus are endemic to North America. They have no aquatic larval stage. In some species, such as the red-backed salamander. Young hatch in the adult form. Members of Plethodon primarily eat small invertebrates. The earliest known fossils of this genus are from the Hemphillian of Tennessee in the United States.
The Douglas squirrel is a pine squirrel found in western North America, from the Pacific Northwest to central California, with an isolated subspecies in northern Baja California, Mexico. It is sometimes known as the chickaree or pine squirrel, although these names are also used for the American red squirrel. Variant spellings of the common name are Douglas' squirrel and Douglas's squirrel. The Native Americans of Kings River called it the "Pillillooeet", in imitation of its characteristic alarm call.
In biology, a ring species is a connected series of neighbouring populations, each of which interbreeds with closely sited related populations, but for which there exist at least two "end populations" in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population and the next. Such non-breeding, though genetically connected, "end populations" may co-exist in the same region (sympatry) thus closing a "ring". The German term Rassenkreis, meaning a circle of races, is also used.
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use.
The long-toed salamander is a mole salamander in the family Ambystomatidae. This species, typically 4.1–8.9 cm (1.6–3.5 in) long when mature, is characterized by its mottled black, brown, and yellow pigmentation, and its long outer fourth toe on the hind limbs. Analysis of fossil records, genetics, and biogeography suggest A. macrodactylum and A. laterale are descended from a common ancestor that gained access to the western Cordillera with the loss of the mid-continental seaway toward the Paleocene.
The arboreal salamander is a species of climbing salamander. An insectivore, it is native to California and Baja California, where it is primarily associated with oak and sycamore woodlands, and thick chaparral.
The Tellico salamander is a small woodland salamander resembling Plethodon glutinosus found in mountainous and lowland regions of southeastern Tennessee and extreme southwestern North Carolina. Little has been published on the species.
The Garden slender salamander or Southern California slender salamander is a species of salamander in the family Plethodontidae. It is endemic to northern Baja California in Mexico and Southern California in the United States.
The white-spotted slimy salamander is a species of salamander in the family Plethodontidae endemic to the Eastern United States. It is one of 55 species in the genus Plethodon, and was one of the first to be described of its cogeners. The preferred habitat of this species is under logs and leaf litter in shaded hardwood forests and wooded floodplains, and often forages on the forest floor on wet nights. It was found that with increasing temperatures, the aggression in this species also increases. In the plethodon genus, species have a lungless morphology, restricting nearly all gas and water exchange transport to the body surface. This species mainly consumes insects, including ants, centipedes, springtails, crickets, millipedes, slugs, snout-beetles, and earthworms. Common predators of this species are gartersnakes, copperheads, and birds. One of their predator defense mechanisms is the release of noxious/sticky substances through the skin by the dorsal granular glands. Another predator deterrent is when touched, this species will freeze in place and become immobile. This species of Plethodon are mostly terrestrial and deposit their direct-developing eggs on land that omits the aquatic larval stage characteristic of most amphibians, therefore this species is not restricted to aquatic habitats for reproduction and dispersal. This species, along with other Plethodontid salamanders, are frequently parasitized by Trombicula mites.
The northern ravine salamander is a species of salamander in the family Plethodontidae. The species is endemic to the United States.
Weller's salamander is a species of salamander in the family Plethodontidae. This species in endemic to the southeastern mountain range of the United States. It is mainly found in North Carolina near Grandfather Mountain. The salamanders have a unique metallic spotting which distinguishes them from other Plethodon species and other salamanders in the area. They mainly inhabit cool forests with rocky areas.
The coastal giant salamander is a species of salamander in the family Dicamptodontidae. It is endemic to the Pacific Northwest of North America. There are three closely related species to this taxon: D. ensatus, D. copei, and D. aterrimus.
There are 14 species of amphibians and 5 species of reptiles known to occur in Mount Rainier National Park.
Robert Cyril Stebbins was an American herpetologist and illustrator known for his field guides and popular books as well as his studies of reptiles and amphibians. His Field Guide to Western Reptiles and Amphibians, first published in 1966, is still considered the definitive reference of its kind, owing to both the quality of the illustrations and the comprehensiveness of the text. A professor of zoology at the University of California, Berkeley, for over 30 years, he was the first curator of herpetology at the Museum of Vertebrate Zoology, a 1949 Guggenheim fellow, and author of over 70 scientific articles. His discovery of the ring species phenomenon in Ensatina salamanders is now a textbook example of speciation, and he performed extensive research on the parietal eye of reptiles. He produced nature films, supported science education in primary grades, and organized conservation efforts that aided in the passing of the 1994 California Desert Protection Act. After retirement he continued to paint, collect field notes, and write books. Stebbins is commemorated in the scientific names of three species: Batrachoseps stebbinsi, the Tehachapi slender salamander; Anniella stebbinsi, a legless lizard; and Ambystoma tigrinum stebbinsi, the endangered Sonora tiger salamander.
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