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Amphiuma means

Garden, 1821

Two-toed Amphiuma

G5Secure Found in 1 roadless area NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.104318
Element CodeAAAAB01010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicendemic to a single nation
KingdomAnimalia
PhylumCraniata
ClassAmphibia
OrderCaudata
FamilyAmphiumidae
GenusAmphiuma
Other Common Names
two-toed amphiuma (EN)
Concept Reference
Frost, D. R. 1985. Amphibian species of the world. A taxonomic and geographical reference. Allen Press, Inc., and The Association of Systematics Collections, Lawrence, Kansas. v + 732 pp.
Taxonomic Comments
Electrophoretic studies of 24 presumptive genetic loci indicated a high level of genetic similarity between A. means and A. tridactylum and a much greater dissimilarity between A. pholeter and A. tridactylum (Karlin and Means 1994).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-05-20
Change Date2001-12-17
Edition Date2025-05-20
Edition AuthorsGundy, R. L. (2025)
Threat ImpactMedium
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
This species is found throughout the Coastal Plain of the southeastern United States where it is widespread and relatively abundant.
Range Extent Comments
This species is endemic to the southeastern United States. The range extends along the Coastal Plain from southeastern Virginia south to throughout the Florida peninsula, and west to eastern Louisiana (Powell et al. 2016, Krysko et al. 2019). Using Global Biodiversity Information Facility (GBIF) (2025) records from 2000-2025, range extent is estimated to be 1.081 million km² (RARECAT 2025)
Occurrences Comments
Applying a 10 km separation distance to GBIF (2025) records from 2000-2025, 308 occurrences are estimated.
Threat Impact Comments
Widespread loss of wetlands due to development and agriculture has undoubtedly eliminated many local populations, but the species remains common in many other areas (Petranka 1998). Droughts may cause localized declines in small wetlands. Mercury has been found in the tissues of this species, though the impacts are unknown (Haskins et al. 2019).
Ecology & Habitat

Habitat

Swamps, bayous, margins of muddy sloughs, cypress heads, drainage ditches, sluggish streams, wet meadows, muddy lakes; soft substrate for burrowing or thick aquatic vegetation important for shelter. Generally found close to shore in the littoral zone (Schalk et al. 2010). Often uses crayfish burrows. May leave water, especially on rainy nights; sometimes found under objects at water's edge. Eggs have been found under objects in damp places near the water's edge and in chambers in sediments where the water has receded. Eggs appear to be specialized for development in terrestrial nest chambers (Gunzburger 2003).

Ecology

Snakes of genus Farancia are the major predators. Other predators include American Alligators (Alligator mississippiensis), Great Blue Herons (Ardea herodias), and Great Egrets (Egretta alba).

Reproduction

Timing of egg deposition is not well known; reportedly eggs are laid in January-February in the north, May-July in the south. Female often remains with eggs during most of incubation (about 5 months). One nest was found unattended inside the nesting mound of an American Alligator (Thompson et al. 2020). Eggs may hatch after inundation, although the timing is unknown (Gunzburger 2003, Thompson et al. 2020). Free-living larval stage may sometimes be absent (Gunzburger 2003).
Palustrine Habitats
TEMPORARY POOLHERBACEOUS WETLANDFORESTED WETLANDRiparian
Other Nations (1)
United StatesN5
ProvinceRankNative
FloridaS4Yes
AlabamaS3Yes
South CarolinaS5Yes
North CarolinaS4Yes
LouisianaS3Yes
GeorgiaS5Yes
MississippiS4Yes
VirginiaS4Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Moderate - slightHigh (continuing)
1.1 - Housing & urban areasRestricted (11-30%)Moderate - slightHigh (continuing)
1.2 - Commercial & industrial areasRestricted (11-30%)Moderate - slightHigh (continuing)
2 - Agriculture & aquacultureRestricted (11-30%)Moderate - slightHigh (continuing)
2.1 - Annual & perennial non-timber cropsRestricted (11-30%)Moderate - slightHigh (continuing)
7 - Natural system modificationsSmall (1-10%)Moderate - slightHigh (continuing)
7.3 - Other ecosystem modificationsSmall (1-10%)Moderate - slightHigh (continuing)
9 - PollutionLarge - restrictedUnknownHigh (continuing)
9.2 - Industrial & military effluentsLarge - restrictedUnknownHigh (continuing)
9.2.2 - Seepage from miningLarge - restrictedUnknownHigh (continuing)
11 - Climate change & severe weatherPervasive (71-100%)Slight or 1-10% pop. declineHigh (continuing)
11.2 - DroughtsPervasive (71-100%)Slight or 1-10% pop. declineHigh (continuing)

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Roadless Areas (1)
North Carolina (1)
AreaForestAcres
Pond Pine BCroatan National Forest2,961
References (23)
  1. Aresco, M. J. 2002. Amphiuma means. Overland migration. Herpetological Review 33:296-297.
  2. Bartlett, R. D., and P. P. Bartlett. 1999b. A field guide to Florida reptiles and amphibians. Gulf Publishing Company, Houston, Texas. xvi + 278 pp.
  3. Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.
  4. Blackburn, L., P. Nanjappa, and M. J. Lannoo. 2001. An Atlas of the Distribution of U.S. Amphibians. Copyright, Ball State University, Muncie, Indiana, USA.
  5. Conant, R. and J. T. Collins. 1991. A field guide to reptiles and amphibians: eastern and central North America. Third edition. Houghton Mifflin Co., Boston, Massachusetts. 450 pp.
  6. Crother, B. I. (editor). 2017. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 8th edition. SSAR Herpetological Circular 43:1-104. [Updates in SSAR North American Species Names Database at: https://ssarherps.org/cndb]
  7. Dundee, H. A., and D. A. Rossman. 1989. The amphibians and reptiles of Louisiana. Louisiana State University Press, Baton Rouge.
  8. Frost, D. R. 1985. Amphibian species of the world. A taxonomic and geographical reference. Allen Press, Inc., and The Association of Systematics Collections, Lawrence, Kansas. v + 732 pp.
  9. Frost, D.R. 2020. Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History, New York, USA. Online: http://research.amnh.org/herpetology/amphibia/index.html
  10. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  11. Gunzburger, M. S. 2003. Evaluation of the hatching trigger and larval ecology of the salamander <i>Amphiuma means</i>. Herpetologica 59:459-468.
  12. Haskins, D. L., A. M. Korotasz, and A. L. Bryan. 2019. Mercury concentrations in the two-toed amphiuma (<i>Amphiuma means</i>) and the lesser siren (<i>Siren intermedia</i>): validating non-lethal sampling methods in southeastern aquatic salamanders. Archives of Environmental Contamination and Toxicology 69(2): 330-335. doi: 10.1007/s00244-019-00657-2
  13. Karlin, A. A., and D. B. Means. 1994. Genetic variation in the aquatic salamander genus Amphiuma. Am. Midl. Nat. 132:1-9.
  14. Krysko, K. L., K. M. Enge, and P. E. Moler. 2019. Amphibians and Reptiles of Florida. University of Florida Press, Gainesville, Florida, USA, 706 pp.
  15. Martof, B. S., W. M. Palmer, J. R. Bailey, and J. R. Harrison, III. 1980. Amphibians and reptiles of the Carolinas and Virginia. University of North Carolina Press, Chapel Hill, North Carolina. 264 pp.
  16. Mount, R. H. 1975. The reptiles and amphibians of Alabama. Auburn University Agricultural Experiment Station, Auburn, Alabama. vii + 347 pp.
  17. Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, D.C.
  18. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  19. Powell, R., R. Conant, and J. T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, fourth edition. Houghton Mifflin Harcourt, Boston and New York. 512 pp.
  20. Salthe, S.N. 1973. Amphiuma means. Catalogue of American Amphibians and Reptiles. 148:1-2.
  21. Schalk, C. M., T. M. Luhring, and B. A. Crawford. 2010. Summer microhabitat use of the greater siren (<i>Siren lacertina</i>) and two-toed amphiuma (<i>Amphiuma means</i>) in an isolated wetland. Amphibia-Reptilia 31: 251-256.
  22. Thompson, L. M., A. C. Wood, H. J. Howell. 2020. <i>Amphiuma means</i>. Reproduction. Herpetological Review 51(2): 289-290.
  23. Tobey, F. J. 1985. Virginia's amphibians and reptiles: a distributional survey. Virginia Herpetological Survey. vi + 114 pp.