Atretochoana eiselti is one of the longest typhlonectids, with the holotype having a total length of 738 mm, with subsequent specimens reaching 1 meter in length (Hoogmoed et al 2011). Based on Wilkinson et al. (1998), this caecilian has a dorsoventrally compressed head, with dorsal eyes in shallow ocular depression; nares countersunk, cheek curved with lower jaws countersunk laterally. The skin is wrinkled, light blue-grey dorsally, lighter ventrally. A white patch is present on the ventral surface of the head between the mandibles and the anterior annuli. The tip of the snout and the areas bordering the mouth are more olive-grey.
A. eiselti is particularly unusual because it lacks lungs, making it the largest lungless tetrapod. The choanal apertures are permanently sealed by fleshy flaps of tissue (Wilkinson and Nussbaum 1997).
Distribution and Habitat
Until the summer of 2011, Aretochoana eiselti was known from only two specimens with unknown locality information. The holotype is marked simply "South America"; the other specimen is probably from Brazil (Wilkinson et al. 1998). In 2011, Hoogmoed and colleagues describe the first specimens with locality information as well as observations in the field, specifically from near the mouth of the Amazon River and the other from 2000 km away in the Madeira River near the border of Brasil and Bolivia (Rondônia state). Wilkinson and Nussbaum (1997) appear to be correct in speculating that it is aquatic; however, the live specimens were found in lowland, warm, turbid waters dispel their hypothesis of preferring montane areas with cold, fast-moving water (Hoogmoed et al 2011). Much remains to be understood of its distribution which is undoubted broad given the large extent between the specimens and observations that Hoogmoed and colleagues report (2011), including a large female that was found in a tidal pool at low tide near Belem on the Atlantic coast.
Life History, Abundance, Activity, and Special Behaviors
Quartz crystals were found in the gut of one specimen, but no useful food remains were present (Wilkinson et al. 1998). Little is known of its life history or behavior although Hoogmoed et al (2011) report that A. eiselti were captured in baited shrimp traps set in shallow waters off of Praia de Marahu on Mosqueiro island north of Belem. They also report that individuals were seen swimming at the surface of the rivers and conjecture that A. eiselti is a strong swimmer given the currents at the Amazon River mouth and the Madeira River.
Trends and Threats
Specimens collected from Rondônia, Brasil, were found in drying pools from the upstream damming of channels in preparation for the new hydroelectric plant Santo Antonio in the Madeira River. At the other site, Hoogmoed et al (2011) observe that raw effluent from nearby Belem is present as is commercial fishing. There is potential for much human impact on this species but is hard to assess without more fieldwork.
Relation to Humans
Unknown. The reclusive nature of caecilians results in little direct interaction with humans.
Possible reasons for amphibian decline
General habitat alteration and loss
Drainage of habitat
Local pesticides, fertilizers, and pollutants
Hoogmoed, M.S., Maciel, A.O., and Coragem, J.T. (2011). ''Discovery of the largest lungless tetrapod, Atretochoana eiselti (Taylor, 1968) (Amphibia: Gymnophiona: Typhlonectidae), in its natural habitat in Brazilian Amazonia.'' Boletim do Museu Paraense Emílio Goeldi. Ciências Naturais, 6(3), 241-262.
Wilkinson, M. and Nussbaum, R.A. (1997). ''Comparative morphology and evolution of the lungless caecilian Atretochoana eiselti (Taylor) (Amphibia: Gymnophiona: Typhlonectidae).'' Biological Journal of the Linnean Society, 62, 39-109.
Wilkinson, M., Sebben, A., Schwartz, E.N.F., and Schwartz, C.A. (1998). ''The largest lungless tetrapod: report on a second specimen of Atretochoana eiselti (Amphibia: Gymnophiona: Typhlonectidae) from Brazil.'' Journal of Natural History, 32, 617-627.
Written by Michelle Knapp (mknapp AT fas.harvard.edu), Harvard University
First submitted 2003-01-09
Edited by Meredith Mahoney, Michelle S. Koo (updated) (2012-02-05)
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