Overview

Brief Summary

Texas blind salamander (Eurycea rathbuni)

The Texas blind salamander is a rare, aquatic, cave-dwelling salamander native to the San Marcos Pool of the Edwards Aquifer, San Marcos, Hays County, Texas [6]. Specimens have been collected at 7 localities in the Purgatory Creek system and along the San Marcos Fault. In some sites it is known only from individuals washed out of artesian wells. Adults and immature larvae are well-adapted to live in underground streams in caves and many probably inhabit deep recesses. Pools where this species has been collected have minimal current and nearly constant temperature of 21-22º [8]. Specimens have been taken in deep pools with minimal current and nearly constant 21-22°C temperatures. The first specimens were collected in 1895 from a newly constructed well that drew water from 58 m below the surface.

The animal has a very broad, flat head and snout and is virtually pigmentless. The four limbs are very thin and elongate; the forelimbs have 4 digits, while the hind limbs have five. The tail is laterally compressed and finned, tapering at its end. The non-functional eyes are vestigial and lie beneath the skin; juveniles have proportionally larger eyes. The animal is neotenic and retains its bright red external gills throughout life; these absorb oxygen from the water. It has 12 costal grooves. Adults are 8.3-14 cm long [9,10]. The animal lives in water-filled subterranean caverns, where it climbs rock surfaces and swims in open water. Its diet varies by what flows into its cave, including blind shrimp, snails, and amphipods [1].

This species is completely aquatic and does not metamorphose. Dunn (2) noted that a laboratory specimen laid a few eggs on March 15 and a specimen collected in early autumn had the spermatheca packed with spermatozoa. Very small juveniles have been found throughout the year, suggesting a seasonal breeding pattern [1] .Bechler [3] saw one complete and two partial courtship bouts in captives where the female initiated courtship and the male remained passive initially. Courtship begins when the female approaches the male and rubs her chin on his dorsum. She may also rub her cloaca on nearby rocks while rocking to and fro. If the male does not respond, the female may nip him along the sides or engage in kicking behavior where gravel is scratched with the hind limbs. She eventually straddles the tail of the male and rubs her snout above the tail base. The male responds by arching his pelvic region and fanning his tail between her legs. The female then rubs her snout more rapidly over the base of the tail. The male may lead the female forward and repeat the same cycle while slowly vibrating the anterior third of the tail. He eventually bends the body laterally and moves the tail laterally at a right angle to the body while the female continues rubbing the base of the tail. The male then leads the female forward, bends his body into an S-shaped pattern and deposits a spermatophore on the substrate. He next leads the female forward with the tail extended laterally until she picks up the spermatophore cap with her cloacal lips. The spermatophore consists of a crescent-shaped white sperm cap over a clear, gelatinous base that is about four times longer than its width. Juvenile dispersal is not considered a migration.

The Texas blind salamander and E. robusta were included in the genus Typhlomolge [4-6]. Although they show extreme specializations for living in underground aquatic systems, they are closely related to other species of Eurycea from Texas and the eastern United States (7,8). xx

Eurycea rathbuni is only found in subterranean water systems in Edwards Plateau in Texas. The Edwards Plateau is characterized by springs and caves and lies at an elevation of 600-750 meters. It has been found in wells but is usually restricted to caves (11). Habitat Regions: temperate ; freshwater Other Habitat Features: caves . At least some populations of this species do not make significant seasonal migrations. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites). Eats various small invertebrates (snails, copepods, amphipods, shrimp). It may feed on snails, shrimp, and amphipods (University of Texas). Bat guano is an important source of nutrients in the subterranean ecosystem inhabited by this species. Apparently no distinct annual or daily activity patterns. Life Cycle: neotenic/paedomorphic; metamorphosis Average lifespan: captivity: 10.3 years. Maximum longevity: 10.3 years (captivity) Gravid females and small juveniles have been found throughout the year. The species is known to be acyclic with females maturing and reproducing throughout the year, unresponsive to seasonal cues. This breeding cycle is typical of many cave dwelling species (Lofts 1974). Breeding of this species has been observed in the laboratory. The females assumes an active role in stimulating the male to mate. Her behavior is characterized by rubbing her chin along the male's back. If this fails to stimulate the male then she may scratch at him or fan her tail at him. She may even resort to nipping at his sides if he further ignores her advances. The male will deposit a spermatophore on a rock or substrate and the female will then pick it up with her cloaca (Bechler 1988). Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous Rounded National Status Rank: N1 - Critically Imperiled. Rounded Global Status Rank: G1 - Critically Imperiled. Reasons: Extremely restricted distribution within a very fragile subterranean ecosystem in Texas; aquifer is threatened by water depletion and potential contamination. Intrinsic Vulnerability: Highly to moderately vulnerable. Environmental Specificity: Very narrow. Specialist or community with key requirements scarce. Red List Category VU Vulnerable Red List Criteria D2. Current Listing Status Summary Status: Endangered. Eurycea rathbuni is listed as endangered under the U.S. Endangered Species Act (Duellman 1999). Its extremely limited range makes it a vulnerable species. US Federal List: endangered; IUCN Red List of Threatened Species: vulnerable. Long Term Trend: Increase of 10-25% to decline of 30%. Comments: Few data, but likely relatively stable in extent of occurrence; uncertain long-term trend in population size, area of occurrence, and number/condition of occurrences. Individuals of this species still appear common in outflows of Diversion Spring, a pipe that carries outflows from the Edwards Aquifer at San Marcos Springs. However, numbers collected vary widely from year to year; currently, most individuals recovered are juveniles (12). Courtship has been observed in captivity. This species has a tail-straddling walk similar to what has been observed in other plethodontid salamanders. Fertilization is by means of a spermatophore deposited on the substrate by the male and picked up in the cloaca by the female (3). Small juveniles have been found throughout the year and breeding may be aseasonal. One gravid female contained 39 mature ova. Known diet items include blind shrimp, snails, and amphipods (1). Degree of Threat: Medium Sensitive to changes in water quality and thus vulnerable to groundwater pollutants (13). Potentially threatened by falling groundwater levels that have resulted from increased pumping to support residential and commercial development in the region. Overcollecting formerly (1960s) may have reduced populations in accessible locations. Major Threats It is sensitive to changes in water quality and thus vulnerable to groundwater pollutants (13). It is potentially threatened by falling groundwater levels that have resulted from increased pumping to support residential and commercial development in the region. Over collecting in the past (1960s) might have reduced populations in accessible locations. This species has a restricted range and is not commonly encountered. Eurycea rathbuni is protected at both local and national levels (8). Management Requirements: Maintenance of water level and quality is the most important management consideration. See recovery plan (14). Biological Research Needs: Research difficult due to the subterranean habitat and fragility of the species. Global Protection: Few (1-3) occurrences appropriately protected and managed. Comments: Listed Endangered by USFWS (F.R. 03-01-78). TNC purchased Ezell's Cave, 1967. Needs: Protect the aquifer from pollution and depletion. Protected by TNC at Ezell's Cave, but would benefit from protection of more abundant populations at other sites. Listed as Endangered by the state of Texas and by the Federal Government. There is a need for continued close monitoring of this species. Eurycea rathbuni does not negatively affect humans. This salamander is not a resource for humans.
  • References[edit]
  • 1. Longley, G. (1978). ''Status of Typhlomolge (= Eurycea) rathbuni, the Texas Blind Salamander.'' Endangered Species Report 2. U.S. Fish and Wildlife Service, Albuquerque, NM, 2:1-45.
  • 2. Dunn (1926).
  • 3. Bechler/Belcher, D.L. 1988. Courtship behavior and spermatophore deposition by the subterranean salamander, Typhlomolge rathbuni (Caudata, Plethodontidae.) Southwestern Naturalist 33 (1): 124 126.
  • 4. Mitchell and Reddell 1965
  • 5. Chippindale et al. 1994
  • 6. Chippindale, P.T., A.H. Price, Wiens, J.J. & Hillis, D.M. (2000): Phylogenetic relationships of central Texas hemidactyliine plethodontid salamanders, genus Eurycea, and a taxonomic revision of the group. Herpetological Monographs 14: 1-80.
  • 7. Chippindale, P. T. (1995). Evolution, phylogeny, biogeography, and taxonomy of Central Texas spring and cave salamanders, Eurycea and Typhlomolge (Plethodontidae: Hemidactyliini. Ph.D Dissertation, University of Texas.
  • 8. Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.
  • 9. University of Texas;
  • 10. Potter, F., S. Sweet. 1981. Generic boundaries in Texas Cave Salamanders, and a Redescription of Typhlomolge robusta (Amphibia: Plethodontidae). Copeia, 1981(1): 64-75.
  • 11. Duellman/Deullman, W. 1999. Patterns of Distribution of Amphibians. Baltimore: The John Hopkins University Press.
  • 12. Chippindale 2005
  • 13. Matthews and Moseley 1990
  • Bockstanz, L., D. Cannatella. 1999. "Herps of Texas-Salamanders" (On-line). Herps of Texas. Accessed December 10, 1999 at http://www.zo.utexas.edu/research/txherps/salamanders/typhlomolge.rathbuni.html.
  • 14. recovery plan (USFWS 1996)
  • ••Hammerson & Chippindale (2004). Eurycea rathbuni. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006. Database entry includes a range map, a brief justification of why this species is vulnerable, and the criteria used.
  • •Hillis, D.M., Chamberlain, D.A., Wilcox, T.P., & Chippindale, P.T. (2001): A new species of subterranean blind salamander (Plethodontidae: Hemidactyliini: Eurycea: Typhlomolge) from Austin, Texas, and a systematic revision of central Texas paedomorphic salamanders. Herpetologica 57: 266-280.
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Comprehensive Description

Description

An aquatic, cave-dwelling salamander. This weird-looking animal is gilled throughout life, has extremely thin limbs, and is virtually pigmentless. The eyes are reduced and non-functional. A tail fin is present. Adults are 9-13.5 cm total length, with 12 costal grooves. Juveniles have proportionally larger eyes. See Petranka (1998) for references.

Until recently E. rathbuni and E. robusta were placed in the genus Typhlomolge. Although they are extreme in their specializations for living in underground aquatic systems, these two species are closely related to other species of Eurycea from Texas and the eastern United States (Chippindale 1995; Petranka 1998).

  • Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.
  • Belcher, D. L. (1988). "Courtship behavior and spermatophore deposition by the subterranean salamander, Typhlomolge rathbuni (Caudata, Plethodontidae)." Southwestern Naturalist, 33, 124-126.
  • Chippindale, P. T. (1995). Evolution, phylogeny, biogeography, and taxonomy of Central Texas spring and cave salamanders, Eurycea and Typhlomolge (Plethodontidae: Hemidactyliini. Ph.D Dissertation, University of Texas.
  • Longley, G. (1978). ''Status of Typhlomolge (= Eurycea) rathbuni, the Texas Blind Salamander.'' Endangered Species Report 2. U.S. Fish and Wildlife Service, Albuquerque, NM, 2:1-45.
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Distribution

endemic to a single state or province

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National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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Global Range: (<100-250 square km (less than about 40-100 square miles)) San Marcos Pool of the Edwards Aquifer, Hays County, south-central Texas (Chippindale et al. 2000).

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Range Description

This species can be found in San Marcos Pool of the Edwards Aquifer, Hays County, south-central Texas, USA (Chippindale et al. 2000). They are unlikely to range beyond this region.
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Historic Range:
U.S.A. (TX)

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Distribution and Habitat

This species has an extremely restricted range and has been found at a small number of localities near San Marcos, Hays Co. Texas. Adults and larvae are adapted for dwelling underground and may occur quite deep. Pools where this species has been collected have minimal current and nearly constant temperature of 21-22º. See Petranka (1998) for references.

  • Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.
  • Belcher, D. L. (1988). "Courtship behavior and spermatophore deposition by the subterranean salamander, Typhlomolge rathbuni (Caudata, Plethodontidae)." Southwestern Naturalist, 33, 124-126.
  • Chippindale, P. T. (1995). Evolution, phylogeny, biogeography, and taxonomy of Central Texas spring and cave salamanders, Eurycea and Typhlomolge (Plethodontidae: Hemidactyliini. Ph.D Dissertation, University of Texas.
  • Longley, G. (1978). ''Status of Typhlomolge (= Eurycea) rathbuni, the Texas Blind Salamander.'' Endangered Species Report 2. U.S. Fish and Wildlife Service, Albuquerque, NM, 2:1-45.
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Geographic Range

The Texas Cave Salamander is limited to the San Marcos, Texas area.

Biogeographic Regions: nearctic (Native )

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Physical Description

Morphology

Physical Description

Eurycea rathbuni is characterized by a very broad, flat head and snout. The four limbs are very thin and elongate. The tail is laterally compressed and finned, tapering at its end. The eyes are vestigial and lie beneath the animal's skin. External gills are bright red and always present. The forelimbs have four digits while the hind limbs have five. Eurycea rathbuni is neotenic and thus bright red gills are present throughout the lifecycle. It has twelve costal grooves as well. Adults range in length from 3.25 to 5.375 inches (University of Texas; Potter and Sweet 1981).

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

  • Potter, F., S. Sweet. 1981. Generic boundaries in Texas Cave Salamanders, and a Redescription of Typhlomolge robusta (Amphibia: Plethodontidae). Copeia, 1981(1): 64-75.
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Size

Length: 14 cm

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Type Information

Holotype for Eurycea rathbuni
Catalog Number: USNM 22686
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1896
Locality: San Marcos, Hays, Texas, United States, North America
  • Holotype: Stejneger, L. 1896. Proc. U. S. Nat. Mus. 18: 620.
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Paratype for Eurycea rathbuni
Catalog Number: USNM 22693
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1896
Locality: San Marcos, Hays, Texas, United States, North America
  • Paratype: Stejneger, L. 1896. Proc. U. S. Nat. Mus. 18: 620.
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Paratype for Eurycea rathbuni
Catalog Number: USNM 22692
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1896
Locality: San Marcos, Hays, Texas, United States, North America
  • Paratype: Stejneger, L. 1896. Proc. U. S. Nat. Mus. 18: 620.
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Paratype for Eurycea rathbuni
Catalog Number: USNM 22689
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1896
Locality: San Marcos, Hays, Texas, United States, North America
  • Paratype: Stejneger, L. 1896. Proc. U. S. Nat. Mus. 18: 620.
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Paratype for Eurycea rathbuni
Catalog Number: USNM 22688
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1896
Locality: San Marcos, Hays, Texas, United States, North America
  • Paratype: Stejneger, L. 1896. Proc. U. S. Nat. Mus. 18: 620.
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Paratype for Eurycea rathbuni
Catalog Number: USNM 22687
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1896
Locality: San Marcos, Hays, Texas, United States, North America
  • Paratype: Stejneger, L. 1896. Proc. U. S. Nat. Mus. 18: 620.
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Ecology

Habitat

Comments: Water-filled subterranean caverns. In some sites, known only from individuals washed out of artesian wells.

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Habitat and Ecology

Habitat and Ecology
It can be found in water-filled subterranean caverns, and have been observed climbing rock surfaces or swimming in open water. In some sites it is known only from individuals washed out of artesian wells. This species is completely aquatic and does not metamorphose. Breeding habits are unknown in nature; however, this species has bred on several occasions in captivity, at the Dallas Aquarium at Fair Park, Cincinnati Zoo, Aquarena Centre (San Marcos), and San Marcos National Fish Hatchery and Technology Centre (L. Ables pers. comm.).

Systems
  • Freshwater
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Eurycea rathbuni is only found in subterranean water systems in Edwards Plateau in Texas. The Edwards Plateau is characterized by springs and caves and lies at an elevation of 600-750 meters. It has been found in wells but is usually restricted to caves (Duellman 1999).

Habitat Regions: temperate ; freshwater

Other Habitat Features: caves

  • Deullman, W. 1999. Patterns of Distribution of Amphibians. Baltimore: The John Hopkins University Press.
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Migration

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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Trophic Strategy

Comments: Eats various small invertebrates (snails, copepods, amphipods, shrimp).

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Food Habits

Little is known about this species feeding habits and methods. It may feed on snails, shrimp, and amphipods (University of Texas).

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Population Biology

Number of Occurrences

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 1 - 5

Comments: Specimens have been collected from several sites, but the number of distinct occurrences is uncertain.

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Global Abundance

Unknown

Comments: Total adult population size is unknown.

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General Ecology

Bat guano is an important source of nutrients in the subterranean ecosystem inhabited by this species.

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Life History and Behavior

Cyclicity

Comments: Apparently no distinct annual or daily activity patterns.

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Life Cycle

Development

Development - Life Cycle: neotenic/paedomorphic; metamorphosis

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Life Expectancy

Lifespan/Longevity

Average lifespan

Status: captivity:
10.3 years.

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Lifespan, longevity, and ageing

Maximum longevity: 10.3 years (captivity)
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Reproduction

See Bechler (1988) for description of courtship behavior. Gravid females and small juveniles have been found throughout the year.

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Little is known about the reproduction of Eurycea rathbuni. The species is known to be acyclic with females maturing and reproducing throughout the year, unresponsive to seasonal cues. This breeding cycle is typical of many cave dwelling species (Lofts 1974). Breeding of this species has been observed in the laboratory. The females assumes an active role in stimulating the male to mate. Her behavior is characterized by rubbing her chin along the male's back. If this fails to stimulate the male then she may scratch at him or fan her tail at him. She may even resort to nipping at his sides if he further ignores her advances. The male will deposit a spermatophore on a rock or substrate and the female will then pick it up with her cloaca (Bechler 1988).

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous

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Conservation

Conservation Status

National NatureServe Conservation Status

United States

Rounded National Status Rank: N1 - Critically Imperiled

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NatureServe Conservation Status

Rounded Global Status Rank: G1 - Critically Imperiled

Reasons: Extremely restricted distribution within a very fragile subterranean ecosystem in Texas; aquifer is threatened by water depletion and potential contamination.

Intrinsic Vulnerability: Highly to moderately vulnerable.

Environmental Specificity: Very narrow. Specialist or community with key requirements scarce.

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IUCN Red List Assessment


Red List Category
VU
Vulnerable

Red List Criteria
D2

Version
3.1

Year Assessed
2004

Assessor/s
Geoffrey Hammerson, Paul Chippindale

Reviewer/s
Global Amphibian Assessment Coordinating Team (Simon Stuart, Janice Chanson, Neil Cox and Bruce Young)

Contributor/s

Justification
Listed as Vulnerable because it is known from only a single location.

History
  • 1996
    Vulnerable
  • 1996
    Vulnerable
    (Baillie and Groombridge 1996)
  • 1996
    Vulnerable
  • 1994
    Endangered
    (Groombridge 1994)
  • 1990
    Endangered
    (IUCN 1990)
  • 1988
    Endangered
    (IUCN Conservation Monitoring Centre 1988)
  • 1986
    Endangered
    (IUCN Conservation Monitoring Centre 1986)
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Current Listing Status Summary

Status: Endangered
Date Listed: 03/11/1967
Lead Region:   Southwest Region (Region 2) 
Where Listed: Entire


Population detail:

Population location: Entire
Listing status: E

For most current information and documents related to the conservation status and management of Eurycea rathbuni, see its USFWS Species Profile

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Eurycea rathbuni is listed as endangered under the U.S. Endangered Species Act (Duellman 1999). Its extremely limited range makes it a vulnerable species.

US Federal List: endangered

IUCN Red List of Threatened Species: vulnerable

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Global Long Term Trend: Increase of 10-25% to decline of 30%

Comments: Few data, but likely relatively stable in extent of occurrence; uncertain long-term trend in population size, area of occurrence, and number/condition of occurrences.

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Population

Population
The total adult population size is unknown. Individuals of this species still appear common in outflows of Diversion Spring, a pipe that carries outflows from the Edwards Aquifer at San Marcos Springs. However, numbers collected vary widely from year to year; currently, most individuals recovered are juveniles (Chippindale 2005).

Population Trend
Stable
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Life History, Abundance, Activity, and Special Behaviors

Very little is known about the biology of this species. Courtship has been observed in captivity. This species has a tail-straddling walk similar to what has been observed in other plethodontid salamanders. Fertilization is by means of a spermatophore deposited on the substrate by the male and picked up in the cloaca by the female (Belcher 1988). Small juveniles have been found throughout the year and breeding may be aseasonal. One gravid female contained 39 mature ova. Known diet items include blind shrimp, snails, and amphipods (Longley 1978).

  • Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.
  • Belcher, D. L. (1988). "Courtship behavior and spermatophore deposition by the subterranean salamander, Typhlomolge rathbuni (Caudata, Plethodontidae)." Southwestern Naturalist, 33, 124-126.
  • Chippindale, P. T. (1995). Evolution, phylogeny, biogeography, and taxonomy of Central Texas spring and cave salamanders, Eurycea and Typhlomolge (Plethodontidae: Hemidactyliini. Ph.D Dissertation, University of Texas.
  • Longley, G. (1978). ''Status of Typhlomolge (= Eurycea) rathbuni, the Texas Blind Salamander.'' Endangered Species Report 2. U.S. Fish and Wildlife Service, Albuquerque, NM, 2:1-45.
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Threats

Degree of Threat: Medium

Comments: Sensitive to changes in water quality and thus vulnerable to groundwater pollutants (Matthews and Moseley 1990). Potentially threatened by falling groundwater levels that have resulted from increased pumping to support residential and commercial development in the region. Overcollecting formerly (1960s) may have reduced populations in accessible locations.

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Major Threats
It is sensitive to changes in water quality and thus vulnerable to groundwater pollutants (Matthews and Moseley 1990). It is potentially threatened by falling groundwater levels that have resulted from increased pumping to support residential and commercial development in the region. Over collecting in the past (1960s) might have reduced populations in accessible locations.
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Life History, Abundance, Activity, and Special Behaviors

This species has a restricted range and is not commonly encountered. Eurycea rathbuni is protected at both local and national levels (Petranka 1998).

  • Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.
  • Belcher, D. L. (1988). "Courtship behavior and spermatophore deposition by the subterranean salamander, Typhlomolge rathbuni (Caudata, Plethodontidae)." Southwestern Naturalist, 33, 124-126.
  • Chippindale, P. T. (1995). Evolution, phylogeny, biogeography, and taxonomy of Central Texas spring and cave salamanders, Eurycea and Typhlomolge (Plethodontidae: Hemidactyliini. Ph.D Dissertation, University of Texas.
  • Longley, G. (1978). ''Status of Typhlomolge (= Eurycea) rathbuni, the Texas Blind Salamander.'' Endangered Species Report 2. U.S. Fish and Wildlife Service, Albuquerque, NM, 2:1-45.
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Management

Management Requirements: Maintenance of water level and quality is the most important management consideration. See recovery plan (USFWS 1996).

Biological Research Needs: Research difficult due to the subterranean habitat and fragility of the species.

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Global Protection: Few (1-3) occurrences appropriately protected and managed

Comments: Listed Endangered by USFWS (F.R. 03-01-78). TNC purchased Ezell's Cave, 1967.

Needs: Protect the aquifer from pollution and depletion. Protected by TNC at Ezell's Cave, but would benefit from protection of more abundant populations at other sites.

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Conservation Actions

Conservation Actions
Listed as Endangered by the state of Texas and by the Federal Government. There is a need for continued close monitoring of this species.
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Relevance to Humans and Ecosystems

Benefits

Economic Importance for Humans: Negative

Eurycea rathbuni does not negatively affect humans.

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Economic Importance for Humans: Positive

This salamander is not a resource for humans.

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Wikipedia

Texas blind salamander

The Texas blind salamander (Eurycea rathbuni) is a rare cave-dwelling troglobite amphibian native to San Marcos, Hays County, Texas, specifically the San Marcos Pool of the Edwards Aquifer. The salamander has blood-red external gills for absorbing oxygen from the water. The salamander's mature length is 13 cm (5 in). Its diet varies by what flows into its cave, including blind shrimp (Palaemonetes antrorum), snails, and amphipods.[1].

Distribution and habitat[edit]

Specimens have been collected at seven localities in the Purgatory Creek system and along the San Marcos Fault near San Marcos, Texas. Adults and immature larvae are well-adapted for living in underground streams in caves, and many probably inhabit deep recesses that are not accessible to collectors. Specimens have been taken in deep pools with minimal current and nearly constant 21-22°C temperatures. The first specimens of this species were collected in 1895 from a newly constructed well that drew water from 58 m below the surface.

Breeding and courtship[edit]

The time of breeding is poorly documented. Dunn (1926) noted a specimen maintained in the laboratory laid a few eggs on March 15 and a specimen collected in early fall had the spermatheca packed with spermatozoa. Very small juveniles have been found throughout the year, suggesting a seasonal breeding pattern [1] Bechler (1988) observed one complete and two partial courtship bouts in captive specimens in which the female initiated courtship and the male remained passive initially. Courtship begins when the female approaches the male and rubs her chin on his dorsum. The female may also rub her cloaca on nearby rocks while rocking to and fro. If the male does not respond, the female may nip the male along the sides or engage in kicking behavior in which gravel is scratched with the hind limbs. The female eventually straddles the tail of the male and rubs her snout above the tail base. The male responds by arching his pelvic region and fanning his tail between her legs. The female then rubs her snout more rapidly over the base of the tail. The male may lead the female forward and repeat the same cycle while slowly vibrating the anterior third of the tail. The male eventually bends the body laterally and moves the tail laterally at a right angle to the body while the female continues rubbing the base of the tail. The male then leads the female forward, bends his body into an S-shaped pattern, and deposits a spermatophore on the substrate. He next leads the female forward with the tail extended laterally until she picks up the spermatophore cap with her cloacal lips. The spermatophore consists of a crescent-shaped white sperm cap over a clear, gelatinous base that is about four times longer than it is wide.

References[edit]

  1. ^ (Longley 1978).
  • Hammerson & Chippindale (2004). Eurycea rathbuni. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006. Database entry includes a range map, a brief justification of why this species is vulnerable, and the criteria used.
  • Chippindale, P.T., A.H. Price, Wiens, J.J. & Hillis, D.M. (2000): Phylogenetic relationships of central Texas hemidactyliine plethodontid salamanders, genus Eurycea, and a taxonomic revision of the group. Herpetological Monographs 14: 1-80.
  • Hillis, D.M., Chamberlain, D.A., Wilcox, T.P., & Chippindale, P.T. (2001): A new species of subterranean blind salamander (Plethodontidae: Hemidactyliini: Eurycea: Typhlomolge) from Austin, Texas, and a systematic revision of central Texas paedomorphic salamanders. Herpetologica 57: 266-280.
  • Bechler, D.L. 1988. Courtship behavior and spermatophore deposition by the subterranean salamander, Typhlomolge rathbuni (Caudata, Plethodontidae.) Southwestern Naturalist 33 (1): 124 126.
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Names and Taxonomy

Taxonomy

Comments: Formerly included in the genus Typhlomolge (see Mitchell and Reddell 1965; Chippindale et al. 1994, 2000).

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