Green-eyed frog (Lithobates vibicarius)

Description

Green-eyed frog fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Green-eyed frog description

Named for its distinctive green eyes, the green-eyed frog (Lithobates vibicarius) is a relatively large frog species with quite variable colouration. Adult green-eyed frogs range from bright green to brassy or reddish-brown on the upperparts, with varying amounts of darker spotting. There is a dark or yellowish-brown stripe running along the side of the face and body ^{(2) (3) (4)}, bordered above by a narrow, greenish-gold line. There is also a light stripe along the upper lip ^{(2) (3)}. The limbs are green or yellowish-brown above, with some brown and gold speckling ⁽³⁾, while the rear surface of the thigh, and often also the underside of the thigh, are bright red ^{(2) (3) (4)}.

The green-eyed frog has a fairly short, wide snout, which looks pointed from above. There is webbing between the toes of the hind feet, and the toe tips are expanded ^{(2) (3)}. Female green-eyed frogs are generally larger than the males ^{(2) (3) (4)}. The tadpoles of the green-eyed frog are large, at up to seven centimetres in length ⁽²⁾, and are generally brown, with a paler underside and a paler tail fin, which has dark spotting ^{(2) (3) (4)}.

The call of the male green-eyed frog is notable for its softness, which is thought to be related to a lack of vocal sacs. Males produce two types of call, described as a harsh trill and an untrilled note ^{(2) (3) (4)}. The trills are given up to five times in succession and may be followed by up to three untrilled notes ⁽³⁾.

Also known as

Rancho Redondo frog.

Synonyms

Levirana vibicaria, Lithobates vibicaria, Rana godmani, Rana vibicaria.

Size

Male length: 6 - 7.3 cm ⁽²⁾

Female length: 6.6 - 9.2 cm ⁽²⁾

Green-eyed frog biology

Male green-eyed frogs usually call at night, from vegetation in water ^{(1) (2)}, and sometimes join together in choruses of up to a hundred or more individuals ^{(2) (4)}. Due to this species’ quiet calls, these choruses may only be audible at relatively short distances ^{(2) (4)}.

The breeding season of the green-eyed frog may coincide with the early rainy season, between May and July ⁽²⁾, although eggs have also been found between November and May ^{(3) (7)}, and some studies report breeding to occur year-round ^{(2) (4)}. The eggs are laid in globular masses, which measure around ten centimetres across and are attached to vegetation or rocks ^{(1) (2) (4)}. Green-eyed frog tadpoles appear to have a long development period ^{(3) (7)}.

Little other information is available on the biology of the green-eyed frog, but adults are reported to be active by both day and night ⁽²⁾.

Green-eyed frog range

Once widespread across the Cordillera de Tilarán, Cordillera Central and Cordillera de Talamanca of Costa Rica and western Panama ^{(1) (2) (3) (4) (5)}, the green-eyed frog is now restricted to Monteverde and the Parque Nacional Juan Castro Blanco in Costa Rica ^{(1) (6)}.

Green-eyed frog habitat

The green-eyed frog inhabits humid montane forest and rainforest, at elevations of around 1,500 to 2,700 metres ^{(1) (2) (3) (5)}. Although it prefers dense forest, it has also been found near water bodies in clearings or pastures ^{(1) (2)}.

This species is semi-aquatic, and breeds in shallow ponds, slow-moving streams or in puddles ^{(1) (2) (3) (4)}.

Green-eyed frog status

The green-eyed frog is classified as Critically Endangered (CR) on the IUCN Red List ⁽¹⁾.

Green-eyed frog threats

Once common in Costa Rica, the green-eyed frog has undergone a drastic decline and was feared to have gone extinct in the country in the 1990s. Fortunately, a population was subsequently rediscovered near Monteverde ^{(1) (6)}, and in 2007 a second population was discovered near to the Parque Nacional Juan Castro Blanco ⁽¹⁾. Unfortunately, the green-eyed frog appears to have disappeared from Panama ⁽¹⁾.

The main cause of the decline in the green-eyed frog is believed to be the fungal disease chytridiomycosis ^{(1) (8)}. There is some evidence to suggest that under natural, unstressed conditions the green-eyed frog can remain largely unaffected by this disease ⁽⁶⁾, but its effects could be compounded by a combination of other threats, including pollution, climate change and habitat loss ^{(1) (7)}. Agricultural chemicals have been blamed for a high level of deformities and a lack of tadpoles in the recently discovered population near the Parque Nacional Juan Castro Blanco ⁽¹⁾.

Green-eyed frog conservation

Conservation work for the green-eyed frog has included assessing and monitoring the wild population, raising local and global awareness of amphibian conservation in Costa Rica, and establishing a captive population at Chester Zoo, in the UK ⁽⁶⁾.

It will be important to continue monitoring the status and health of the remaining green-eyed frog populations, and to protect and maintain the species’ habitat at the two known sites at which it occurs ^{(1) (6)}. This rare amphibian would also benefit from further research into its biology, behaviour and genetic diversity, as well as from fieldwork to determine whether it still occurs at any other locations ⁽⁶⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

Find out more about the green-eyed frog and its conservation:

• AmphibiaWeb:
  http://www.amphibiaweb.org/

More information on amphibian conservation:

• Amphibian Ark:
  http://www.amphibianark.org/
• IUCN/SSC Amphibian Specialist Group:
  http://www.amphibians.org/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Genetic diversity

The variety of genes within a particular species, population or breed causing differences in morphology, physiology and behaviour.

Montane forest

Forest occurring in the montane zone, a zone of cool upland slopes below the tree line dominated by large evergreen trees.

References

1. IUCN Red List (April, 2011)
   http://www.iucnredlist.org/
2. Savage, J.M. (2002) The Amphibians and Reptiles of Costa Rica: A Herpetofauna between Two Continents, between Two Seas. University of Chicago Press, Chicago.
3. AmphibiaWeb (April, 2011)
   http://www.amphibiaweb.org/
4. Zweifel, R.G. (1964) Distribution and life history of a Central American frog, Rana vibicaria. Copeia, 1964(2): 300-308.
5. Frost, D.R. (2011) Amphibian Species of the World: An Online Reference. American Museum of Natural History, New York. Available at:
   http://research.amnh.org/vz/herpetology/amphibia/
6. Wainwright, M. and Gray, A. (2009) Conservation of the Critically Endangered Green-eyed Frog, Lithobates vibicarius. Project Report, Frog Blog Manchester. Available at:
   http://frogblogmanchester.files.wordpress.com/2009/05/lithobates-vibicarius-project-report.pdf
7. Lips, K.R. (1998) Decline of a tropical montane amphibian fauna. Conservation Biology, 12(1): 106-117.
8. Lips, K.R., Green, D.E. and Papendick, R. (2003) Chytridiomycosis in wild frogs from southern Costa Rica. Journal of Herpetology, 37(1): 215-218.