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Brief Summary

    Barton Springs salamander: Brief Summary
    provided by wikipedia

    The Barton Springs salamander (Eurycea sosorum) is an endangered lungless salamander that only lives in the habitat of Barton Springs in Austin, Texas, USA. Barton Springs salamanders are average-sized (adults grow to approximately 6.4 centimetres (2.5 in) in total length) and have mottled coloration varying from darkish purple to light yellow.

Comprehensive Description

    Barton Springs salamander
    provided by wikipedia

    The Barton Springs salamander (Eurycea sosorum) is an endangered lungless salamander that only lives in the habitat of Barton Springs in Austin, Texas, USA.[3] Barton Springs salamanders are average-sized (adults grow to approximately 6.4 centimetres (2.5 in) in total length) and have mottled coloration varying from darkish purple to light yellow.[2]

    Environmental impact

    Amphibian species worldwide have been in decline due to climate change including but not limited to: increased UV radiation, change in precipitation, and various pathogen outbreaks (chytrid fungus[4] which causes Chytridiomycosis[4]). However, habitat destruction, degradation, and pollution on a local scale have resulted mainly from land and watershed urbanization. These changes, in turn, affect, among others, water quality and biological community composition of rivers and water systems in the surrounding environment. The wide effects of contamination and degradation on these water systems make analyzing their specific sources difficult since the interactions of factors and overlapping effects may occur. Nonetheless, it is important to study these consequences so that future impact on this and other species may be reduced.[5]

    Oxygen absorption

    Dissolved oxygen (DO) is required at specific levels to maintain healthy aquatic life. To do this, "national ambient water quality criteria"[5] have been set by the U.S. Environmental Protection Agency and measurements have been made since 1969, albeit inconsistently. Hypoxia, a state of reduced oxygen, may hinder embryonic and fetal development as well as decrease oxygen consumption in adults. Apart from prenatal developments, physiological responses may also arise from a lack of oxygen. Some of the known responses include "Increases in heart rate and buccal pumping, behavioral hypothermia, and gill hypertrophy".[5]

    Since this species is an obligately aquatic neotene, retains its gills through its adult life, it must absorb oxygen through its gills or skin. However, the method in which it performs this absorption has yet to be determined. One study found that when presented with a low DO level, this salamander increases its body movement. They theorized two explanations for this reaction:

    1. low and high DO levels may be found relatively close, therefore movement will allow this species to migrate to a higher DO environment,
    2. the physical movement causes a decrease between boundary layers adjacent to skin and gills, which allows for greater flow of oxygen.[5]

    Diet and behavior

    Much of the Barton Springs salamander's life history remains unknown at this time. It appears that they feed primarily on small aquatic crustaceans, but can supplement their diet with other items, such as earthworms.[6] In addition, aquatic vegetation has been shown to be a critical component to the salamander's habitat; their numbers dropped precipitously after the removal of much of the vegetation from Barton Springs, and have recovered after habitat restoration programs were implemented.[6]

    Etymology

    The species epithet (sosorum) is an acronym for "Save Our Springs Ordinance" (of the City of Austin) although it is widely if erroneously believed to refer to SOS Alliance, a local preservation group[7] combined with a Latin genitive plural ending.[2]

    Conservation status

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    Preserved specimen

    Despite inhabiting an urban area, E. sosorum was not described until 1993.[2] It was put on the federal List of Threatened and Endangered Species in 1997.[6] The salamander's listing prevented the City of Austin from cleaning the Barton Springs Pool as it had for 70 years—with bleach. As a result, the City of Austin applied for and was issued an Incidental Take Permit under Section 10(a)(1)(b) of the Endangered Species Act by the U.S. Fish and Wildlife Service in 1998. The permit has a term of 15 years and allows incidental taking of salamanders during pool cleaning and maintenance. As a mitigation measure, the City offered to direct 10% of revenue generated through pool entry fees into a conservation fund that is used for research and habitat enhancement.

    References

    1. ^ Geoffrey Hammerson; Paul Chippindale (2004). "Eurycea sosorum". The IUCN Red List of Threatened Species. IUCN. 2004: e.T8392A12909469. doi:10.2305/IUCN.UK.2004.RLTS.T8392A12909469.en. Retrieved 8 November 2017..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
    2. ^ a b c d Chippindale, P.T.; A.H. Price; Hillis, D.M. (1993). "A new species of perennibranchiate salamander (Eurycea, Plethodontidae) from Austin, Texas" (PDF). Herpetologica. 49: 242–259.
    3. ^ Frost, Darrel R. (2014). "Eurycea sosorum Chippindale, Price, and Hillis, 1993". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 4 April 2014.
    4. ^ a b Gaertner, J.P.; Forstner, M.R.J; O'Donnell, L.; Hahn, D. (2009). "Detection of Batrachochytrium dendrobatidis in Endemic Salamander Species from Central Texas". Ecohealth. 6 (1): 20–26. doi:10.1007/s10393-009-0229-x. PMID 19424755.
    5. ^ a b c d Woods, H.A.; Poteet, M.F.; Hitchings, P.D.; Brain, R.A.; Brooks, B.W. (2010). "Conservation Physiology of the Plethodontid Salamanders Eurycea nana and E. sosorum: Response to Declining Dissolved Oxygen". Copeia. 2010 (4): 540–553. doi:10.1643/CP-09-026.
    6. ^ a b c "Barton Springs Salamander (Eurycea sosorum)". Texas Parks and Wildlife Department. Retrieved 15 January 2012.
    7. ^ "Biodiversity". Sosalliance.org. 2010-09-13. Retrieved 2011-07-29.

Distribution

    Distribution
    provided by Animal Diversity Web

    Barton Springs of Zilker Park in Austin, Travis County, Texas. E. sosorum is restricted to and only found in two (Parthenia and Eliza) of the four hydrologically connected pools collectively named Barton Springs. E. sosorum is the only extant salamander species found in these two pools. No evidence exists that indicates E. sosorum is found anywhere else. This means that E. sosorum has the smallest habitat of any vertebrate in the world. (Chippindale et al 1993; Deanna Chamberlain, personal communication)

    Biogeographic Regions: nearctic (Native )

Morphology

    Morphology
    provided by Animal Diversity Web

    The average length of the Barton Springs salamander is 6.35 cm. The organism is small and is known for its fairly small head, reduced eyes (with a golden iris and black mottling), shovel-nosed snout, slender body and elongate limbs. E. sosorum has a very distinctive dorsal coloration known as the "salt and pepper" effect. Dorsal color varies in life from dark through medium gray to purplish gray or gray-brown to yellowish brown to yellowish cream. The varied degrees of blotched and mottled specks are attributed to an irregular mixture of (or lack of) melanophores, iridophores and pigment gaps. Overall, the mottled pattern gives the salamander olive brown specks with a base color of yellowish cream. The presence of silvery-white iridophores enhances the salamanders' luster. Some salamanders appear pale due to the lack of melanophores. The trunk of E. sosorum is finely speckled with melanophores while the ventral surface is creamy to translucent in color. Sometimes the stomach contents, as well as the presence of eggs in females, can be seen through the translucent skin. Dorsally, the limbs of E. sosorum, are unevenly speckled as well as the toes. Ventrally, the limbs are not speckled. In addition the relatively short tail of E. sosorum has an uneven distribution of melanophores. On the ventral surface of the tail the salamander has a narrow, orange-yellow strip from the posterior margin of cloacal vent to the tip. Furthermore, unique traits of barton spring salamanders include: three pairs of brightly-colored, red gills, four fingers on each hand, five toes on each foot and 16 pre-sacral vertebrae. These traits set Eurycea sosorum apart from other Central Texas Eurycea. (Petranka 1998; Deanna Chamberlain, personal communication; Chippindale et al 1993)

    Other Physical Features: ectothermic ; bilateral symmetry

Habitat

    Habitat
    provided by Animal Diversity Web

    E. sosorum prefers clear waters and is mostly concentrated near the spring openings where food supplies are abundant, water chemistry and temperatures are constant and access to surface and subsurface habitats is available. Barton Springs salamanders are also found under rocks and gravel immediately adjacent to main spring outflows and within aquatic vegetation and algae mats. E. sosorum lives in water depths ranging from 0.1 to 5 meters. The springs where the salamanders are found flow year long and remain at a constant temperature of twenty degrees Celsius. E. sosorum in generally not found on exposed on limestone surfaces or in silted areas within the pools. Monthly population counts done by the city of Austin show that the Parthenia pool population may range anywhere from 90 - 150 salamanders and the Eliza pool has an average population of 30 salamanders. (Deanna Chamberlain personal communication; Rogers 1997)

    Aquatic Biomes: rivers and streams

Trophic Strategy

    Trophic Strategy
    provided by Animal Diversity Web

    The diet of E. sosorum consists primarily of the small invertebrate Hyalla azteca, an amphipod. E. sosorum also feeds on snails, crustaceans, black worms, leeches and bug larvae. In captivity the salamanders feed on earthworms, brine shrimp, white worms and commercial food pellets. Predators of E. sosorum are small fish and crayfish. (Deanna Chamberlain, personal communication; Bishop 1967; Rogers 1997)

Life Cycle

    Life Cycle
    provided by Animal Diversity Web

    Development - Life Cycle: metamorphosis

Reproduction

    Reproduction
    provided by Animal Diversity Web

    Not many details of the reproduction of E. sosorum are known. This is due to the secretive and nocturnal nature of salamanders in general. In the wild, females have been found holding, at the maximum, forty eggs from September through January. It is known that females carry their eggs for a year before depositing them It takes one year for larvae to reach sexual maturity and all sexually mature individuals that have been found have been longer than 22.5 mm. Also in their native habitat, young hatchlings have been found in November, March and April. This evidence suggests that breeding takes place year round. In the wild, no deposited eggs have ever been found or seen. It is believed the E. sosorum may deposit it's eggs in the Edwards Aquifer which feeds the pools where they live. The Edwards Aquifer is a karst aquifer which means that it is very porous. Due to the small size of the salamander this hypothesis could be true. However, in captivity Barton Spring salamanders deposit their eggs on plastic plants in string-like clusters. The eggs are 1.5 mm in diameter and are surrounded by two jelly layers. They are easily observed because of their white color and iridiscent properties.

    (Deanna Chamberlain, personal communication; Bishop 1967; Petranka 1998)

    As of 1999, in captive-breeding programs, females have deposited eggs twenty times. Of the eggs deposited, larvae only developed twice and none survived to sexual maturity. What has been noted in the embryos is that after 19 days eyes develop and then, after 38 days, limb bud and gill structure is observed.

    (Deanna Chamberlain, personal communication)

    Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate)

Conservation Status

    Conservation Status
    provided by Animal Diversity Web

    Barton Springs salamanders have been proclaimed an endangered species by the U.S. Fish and Wildlife Service. E. sosorum was first found in Barton Springs during the 1940's, and numbered in the hundreds. However, in the past decade, fewer than 20 specimens were observed over six month periods and none at other times. In addition, the number of dead salamanders found was increasing. The drastic decrease in the E. sosorum population was credited to the decrease in water quality and quantity of the Edwards Aquifer and even more specifically the Barton Creek Watershed which feeds the aquifer. This decline is the result of increased urbanization and environmental pollution. Also, improper cleaning of the Parthenia pool of Barton Springs (used for recreational swimming) drastically disturbed the chemical and physical equilibriums of the salamanders' habitat. In the past two to three years environmental activists have petitioned for environmentally safer ways for cleaning the pool, bringing greatly needed attention to the water quality and quantity issues concerning Barton Springs as well as the Edwards aquifer. (Rogers 1997; Deanna Chamberlain, personal communication)

    US Federal List: endangered

    IUCN Red List of Threatened Species: vulnerable

Benefits

    Benefits
    provided by Animal Diversity Web

    Since the placement of E. sosorum on the U.S. ESA endangered species list, major restrictions have taken place on the urban development within the main watersheds of the Edwards Aquifer in Austin, TX. (Rogers 1997)

Other Articles

    Untitled
    provided by Animal Diversity Web

    Even though Barton Spring Salamanders have been observed in their natural habitat for the last fifty years, it was not until 1993 that E. sosorum was formally declared a separate species. In the Central Texas area other Eurycea salamanders such as E. neotenes and E. nana are in similar positions such as E. sosorum in that they are extremely environmentally sensitive organisms, limited to one or two populations, which makes them vulnerable to extinction. One major environmental disaster in any of the watersheds that feed the Edwards aquifer (that in turn feeds the springs where these salamanders live) could possibly eliminate the already dwindling populations. An interesting sidenote is that the species name of Eurycea sosorum came from Austin legislation during the early 1990's, known as Save Our Springs (S.O.S.), in regards to increasing environmental protection over Barton Springs. (Rogers 1997; Petranka 1998; Bishop 1967; Chippindale et al 1993)