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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Rio Cauca Caecilian

Synonyms and Other Names: Typhlonectes compressicauda natans Fischer in Peters 1880, Chthonerpeton haydee Roze 1963, Typhlonectes venezuelensis Taylor 1968, Nectocaecilia cooperi Taylor 1970

Rubber eel

Taxonomy: available through www.itis.gov

Identification: The Rio Cauca Caecilian is a member of the order Gymnophiona and is a limbless amphibian with fleshy segmented folds along its body and ranges from dark gray to purplish to black in color. Rio Cauca Caecilians are morphologically similar to the Cayenne Caecilian (Typhlonectes compressicauda). They can be differentiated from Cayenne Caecilians by relative width of the head (T. natans has a wider head than body and T. compressicauda has a narrower head than body; Taylor 1968; Maciel and Hoogmoed 2011), tooth shape (T. natans has sharper tooth tips; Wilkinson 1991), and the number of anal denticulations (T. natans has 9 and T. compressicauda has 10-11; Taylor 1968; Maciel and Hoogmoed 2011).

Size: Maximum length of 45-55 cm (18-22 in).

Native Range: The Cauca and Magdalena River drainage basins in Colombia, the Maracaibo Basin in Venezuela and surrounding areas (Tapley and Acosta-Galvis 2010; AmphibiaWeb 2023), and perhaps Trinidad and Tobago but this needs confirmation (IUCN 2020).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Rio Cauca Caecilians are relatively elusive, and little is known about their behavior and ecology. They are believed to be fully aquatic and inhabit warm freshwater marshes, ponds, streams, and rivers. Caecilians in the family Typhlonectidae have been observed in mud burrows, under rocks, in aquatic vegetation, and open water (Kupfer et al. 2006). Due to their subterrain lifestyle, caecilians have poor eyesight and are mostly blind (Mohun et al. 2010); Van Hoose 2021). Rio Cauca Caecilians have the ability to breathe air, but the majority of respiration happens through their skin (Van Hoose 2021). Rio Cauca Caecilians are viviparous, giving birth to live young, and females usually have two to 10 offspring per litter (Reinhard and Kupfer 2022). Reinhard and Kupfer (2022) also found that female body size impacts the quality of the litter, thus larger females had more and larger offspring. Little is known about the wild diet of Rio Cauca Caecilians; however, they have been observed eating fish entrails suggesting that they are both scavengers and predators (Kupfer et al. 2006). In captivity, typhlonectids are often fed earthworms, crickets, beetle larvae, frozen fish, crustaceans, and commercially available amphibian pellet (Tapley et al. 2019).

Means of Introduction: Rio Cauca Caecilians are often exported from Columbia, are widely available in the pet and aquarium trade, and commonly bred in captivity by hobbyists (Wake 1994; Tapley and Acosta-Galvis 2010). A Rio Cauca Caecilian was collected in Miami-Dade County, Florida in 2019 and is considered to be the first caecilian collected in the United States (Sheehy et al. 2021). Its introduction into Florida was likely the result of an aquarium release or escape. 

Status: Status in Florida is unknown.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: Rio Cauca Caecilians are often kept in aquaria and captive bred, however there is not consensus on exact captive requirements such as temperature and water parameters (Tapley and Acosta-Galvis 2010). It is thought that water harder than 150ppm could cause skin irritation, lesions, and even death (Whitaker and Wright 2001).

References: (click for full references)

AmphibiaWeb. 2023. University of California, Berkeley, California, USA. https://
amphibiaweb.org (accessed on 2/28/23)

IUCN SSC Amphibian Specialist Group. 2020. Typhlonectes natans. The IUCN Red List of Threatened
Species 2020: https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T59601A85909110.en. Accessed on 08 March 2023.

Kupfer, A., P. Gaucher, M. Wilkinson, and D. Gower. 2006. Passive trapping of aquatic caecilians
(Amphibia,  Gymnophiona,  Typhlonectidae) Studies on Neotropical Fauna and Environment. 41:93-96. https://doi.org/10.1080/01650520500443930

Maciel, A.O. and M.S. Hoogmoed. 2011. Taxonomy and distribution of caecilian amphibians
(Gymnophiona) of Brazilian Amazonia, with a key to their identification. Zootaxa 2984:1–53. https://doi.org/10.11646/zootaxa.2984.1.1

Mohun, S. M., W. L. Davies, J. K. Bowmaker, D. Pisani, W. Himstedt, D. J. Gower, D. M. Hunt, and M.
Wilkinson. 2010. Identification and characterization of visual pigments in caecilians (Amphibia: Gymnophiona), an order of limbless vertebrates with rudimentary eyes. J Exp Biol, 213 (20): 3586–3592. https://doi.org/10.1242/jeb.045914

Reinhard, S. and A. Kupfer. 2022. Maternal investment in the viviparous caecilian amphibian
Typhlonectes natans (Gymnophiona: Typhlonectidae). Zoologischer Anzeiger 296:33-36. https://doi.org/10.1016/j.jcz.2021.11.002

Sheehy, C., D. Blackburn, M. Kouete, K. Gestring, K. Laurie, A. Prechtel, E. Suarez, and B. Talley. 2021.
First record of a caecilian (order Gymnophiona, Typhlonectes natans) in Florida and in the United States. Reptiles & Amphibians, 28(2):355–357. https://doi.org/10.17161/randa.v28i2.15629

Tapley, B. and A.R. Acosta-Galvis. 2010. Distribution of Typhlonectes natans in Colombia, environmental
parameters and implications for captive husbandry. The Herpetological Bulletin 113:23–29.

Tapley, B.J., D. Gower, C.J. Michaels, A. Barbon, M. Goetz, J. Lopez, A. Bland, G.Garcia, N.A. Nelson, and
M. Wilkinson. 2019. EAZA Amphibian Taxon Advisory Group Best practice guidelines for typhlonectid caecilians. https://doi.org/10.13140/RG.2.2.22002.25283

Taylor, E.H. 1968. The Caecilians of the World. A Taxonomic Review. University of Kansas Press,
Lawrence, Kansas, USA

Van Hoose, N. 2021. Weird, noodle-shaped amphibians known as caecilians found in South Florida
canal. Florida Museum of Natural History. https://www.floridamuseum.ufl.edu/science/caecilians-found-in-south-florida/ (accessed on 2/28/23)

Wake, M.H. 1994.  Caecilians in captivity. Pages 223-228 in J.B. Murphy, K. Adler, and J.T. Collins, editors.
Captive Management and Conservation of Amphibians & Reptiles. Captive Management and Conservation of Amphibians & Reptiles. Society for the Study of Reptiles and Amphibians, Ithaca, New York.

Whitaker, B.R. and K.N. Wright. 2001. Amphibian Medicine and Captive Husbandry. Krieger
Publishing Company, Malabar, Florida.

Wilkinson, M. 1991. Adult tooth crown morphology in the Typhlonectidae (Amphibia: Gymnophiona): a
reinterpretation of variation and its significance. Journal of Zoological Systematics and Evolutionary Research 29(4):304–311. https://doi.org/10.1111/j.1439-0469.1991.tb00675.x
 

Author: Reaver, K.M.

Peer Review Date: 10/4/2023

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.