Ensatina

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Ensatina
Ensatina eschscholtzii eschscholtzii.jpg
Monterey Ensatina (Ensatina eschscholtzii eschscholtzii)
Scientific classification OOjs UI icon edit-ltr.svg
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
  • Ensatina klauberi
  • Heredia oregonensis
  • Plethodon croceater
  • Urotropis platensis

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.

Contents

Description

Ensatina eschscholtzii klauberi, the large-blotched ensatina Ensatina eschscholtzii klauberi.jpg
Ensatina eschscholtzii klauberi, the large-blotched ensatina
E. eschscholtzii eschscholtzi, the Monterey ensatina Ensatina eschscholtzii e.jpg
E. eschscholtzii eschscholtzi, the Monterey ensatina

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]

As a ring species

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]

Distribution and habitat

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.

Relationships with humans

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]

Subspecies

E. e. platensis from Fresno County, California Ensatina eschscholtzii platensis (3405603045).jpg
E. e. platensis from Fresno County, California

Related Research Articles

<i>Plethodon</i> Genus of amphibians

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.

<span class="mw-page-title-main">Douglas squirrel</span> Species of rodent

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.

<span class="mw-page-title-main">Ring species</span> Connected series of neighbouring populations

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.

<span class="mw-page-title-main">Species complex</span> Group of closely related similar organisms

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.

<span class="mw-page-title-main">Long-toed salamander</span> Species of amphibian

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.

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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.

<span class="mw-page-title-main">Garden slender salamander</span> Species of slender salamander

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<span class="mw-page-title-main">White-spotted slimy salamander</span> Species of amphibian

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.

<span class="mw-page-title-main">Northern ravine salamander</span> Species of amphibian

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<span class="mw-page-title-main">Weller's salamander</span> Species of amphibian

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.

<span class="mw-page-title-main">Coastal giant salamander</span> Species of amphibian

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<span class="mw-page-title-main">Robert C. Stebbins</span> American herpetologist

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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References

  1. IUCN SSC Amphibian Specialist Group (2022). "Ensatina eschscholtzii". IUCN Red List of Threatened Species . 2022: e.T59260A196339088. doi: 10.2305/IUCN.UK.2022-1.RLTS.T59260A196339088.en . Retrieved 1 May 2024.
  2. 1 2 3 Wake, D. (1997). "Incipient species formation in salamanders of the Ensatina complex". Proceedings of the National Academy of Sciences USA. 94 (15): 7761-7767. Bibcode:1997PNAS...94.7761W. doi: 10.1073/pnas.94.15.7761 . PMC   33701 . PMID   9223261.
  3. Monterey Ensatina San Diego Field Station, United States Geological Survey Viewed: April 24, 2005, Last updated: March 05, 2003[ permanent dead link ]
  4. Carl T. Bergstrom; Lee Alan Dugatkin (2012). Evolution. Norton. p. 468. ISBN   978-0-393-92592-0.
  5. Grismer, L. Lee (2019-12-31). Amphibians and Reptiles of Baja California, Including Its Pacific Islands and the Islands in the Sea of Cortés. University of California Press. doi:10.1525/9780520925205. ISBN   978-0-520-92520-5.
  6. Dawkins, R. (2004). "Ring Species (The Salamander's Tale)". The Ancestor's Tale: A Pilgrimage to the Dawn of Life. Houghton Mifflin Harcourt. ISBN   0-618-00583-8.[ page needed ]
  7. Dobzhansky T. (1958). Barnett S A (ed.). A Century of Darwin. Cambridge, MA: Harvard Univ. Press. pp. 19–55.
  8. Highton, Richard (June 1998). "Is Ensatina eschscholtzii a Ring-Species?". Herpetologica. 54 (2): 254–278. JSTOR   3893431.
  9. Valdez-Villavicencio, Jorge Heriberto; Peralta-Garcia, Anny; Hollingsworth, Bradford Damion (2015-05-01). "A coastal population of Large-blotched Ensatina Ensatina klauberi (Caudata: Plethodontidae) in Baja California, México". Check List. 11 (3): 1649. doi: 10.15560/11.3.1649 . ISSN   1809-127X.
  10. Kuchta, Shawn R (April 2008). "Why does the yellow-eyed Ensatina have yellow eyes? Batesian mimicry of Pacific newts (genus Taricha) by the salamander Esatina eschscholtzii xanthoptica". Evolution. 62 (4): 984–990. doi: 10.1111/j.1558-5646.2008.00338.x . PMID   18248632. S2CID   998486.