AMPHIBIAWEB
Ceratophrys ornata
Bell's Horned Frog, Escuerzo
family: Ceratophryidae

© 2006 John White (1 of 7)
Conservation Status (definitions)
IUCN (Red List) Status Near Threatened (NT)
CITES No CITES Listing
Other International Status None
National Status None
Regional Status None

 

View distribution map using BerkeleyMapper.

   

Description
These frogs are large frogs (average SVL of both sexes of 112.4 mm +/-13.4 mm, n = 34; Basso 1990) with wide heads and enormous mouths. Strong jaw teeth (Achaval and Olmos 2003). Tympanum is visible (Achaval and Olmos 2003). No webbing is present on digits (Achaval and Olmos 2003). The skin of the head and back is attached to underlying bone (Achaval and Olmos 2003). Eyelids have a well-marked projection (Achaval and Olmos 2003). For Uruguayan specimens, the dorsal color is dark green with brown red, and yellow spots, and a V-shaped marking is present between the eyes (Achaval and Olmos 2003). Color may also be brown (Bartlett and Bartlett 2000). The edges of the mouth are yellow (Achaval and Olmos 2003). In the male the gular area appears mottled (Achaval and Olmos 2003). The venter is quite granular in Ceratophrys ornata from Tigre, Buenos Aires, Argentina (Canziani and Cannata 1979).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Argentina, Brazil, Uruguay

 

View distribution map using BerkeleyMapper.
Ceratophrys ornata is found in Argentina (the Pampean region: Buenos Aires, Cordoba, Entre Ríos, La Pampa, Mendoza, and Santa Fe provinces), Uruguay, and southern Brazil (Río Grande do Sul), from 0-500 m asl. Habitat includes grassland near temporary bodies of water, as well as in irrigated cropland and in ditches (Stuart et al. 2008).

Life History, Abundance, Activity, and Special Behaviors

Frogs of the genus Ceratophrys are sit-and-wait predators, partially concealing themselves in the leaves of the forest floor and remaining motionless most of the time (Duellman and Lizana 1994). When prey approaches, the animal quickly attacks, usually swallowing the prey whole (Duellman and Lizana 1994). Ceratophrys ornata consumes primarily vertebrates; stomach content analysis of thirty-four specimens from Uruguay included 78.5% anurans, 11.7% passerine birds, 7.7% rodents, and 0.3% snakes, leaving only 1.8% as "other" (Basso 1990).

It burrows during autumn and winter (Canziani and Cannata 1979). While buried, it creates a cocoon around itself to protect from water loss (Canziani and Cannata 1979). It emerges to breed in the late spring, when enough rain has fallen to create temporary pools (Canziani and Cannata 1979). Eggs are laid on the bottom of these temporary ponds (Stuart et al. 2008).

Tadpoles of this species can make distress calls both underwater and out of water. This is the first example of any larva (vertebrate or invertebrate) communicating underwater by sound, as well as the first known of any vertebrate larva to make sounds at all. C. ornuta tadpoles are able to make these calls as early as three days after hatching, and can do so both in the water and out of the water. It is not known how other tadpoles perceive the calls, but while C. ornata larvae are carnivorous towards tadpoles of other species, they do not consume conspecific tadpoles. To hear the sound, check out the two video clips in the associated BBC news story.

Trends and Threats
This species is rare in Argentina and appears to have disappeared from at least two sites in Uruguay (Rocha and San Jose, in Laguna de Castillos and Delta del Tigre, respectively). The major threat is habitat loss from agriculture and housing developments, although C. ornata does occur within some protected areas. Water and soil pollution from agriculture, industry, and human settlements also present threats. It is collected for the pet trade. Eggs are used in laboratory research on developmental biology (Stuart et al. 2008).

Relation to Humans
This species is popular as a pet (Stuart et al. 2008). While the official vernacular name is Bell's Horned frog, many people refer to frogs in the genus Ceratophrys as "pac-man" frogs (from the old Pac-Man video game) since the body plan appears to be mostly dominated by the large, gaping mouth (Bartlett and Bartlett 2000). In some areas this frog is (wrongly) regarded as venomous, resulting in eradication attempts (Stuart et al. 2008).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Urbanization
Local pesticides, fertilizers, and pollutants
Intentional mortality (over-harvesting, pet trade or collecting)

Comments

This species was first described by Günther (1859).

It has been reported that C. ornata are octoploid (Schmid et al. 1985); individuals analyzed were collected in Argentina but the locality was not given, raising the possibility that the specimens might have been C. cranwelli.

Records referred to as C. ornata from the Chacoan region of Argentina (cf. the South Chaco specimens of Canziani and Cannata 1979) are actually Ceratophrys cranwelli (Cei 1987), as are records from Paraguay (Brusquetti and Lavilla 2006).

References

Bartlett, R. D., and Bartlett, P. (2000). The horned frog family and African bullfrogs. Barron's Educational Series, Inc., New York.

Basso, N. G. (1990). ''Estrategias adaptivas en una comunidad subtropical de anuros.'' Cuadernos de Herpetologia Serie Monografías, 1, 1-70.

Braun, P. C. and Braun, C. A. S. (1980). ''Lista prévia dos anfíbios do Estado do Rio Grande do Sul, Brasil.'' Iheringia, 56, 121-146.

Brusquetti, F., and Lavilla, E.O. (2006). ''Lista comentada de los anfibios de Paraguay.'' Cuadernos de Herpetologica, 20, 3-79.

Canziani, G. A., and Cannata, M. A. (1980). ''Water balance in Ceratophrys ornata from two different environments.'' Comparative Biochemistry and Physiology , 66A, 599-603.

Cei, J. M. (1980). ''Amphibians of Argentina.'' Monitore Zoologica Italiano, New Series Monografia, Firenze, 2, 1-609.

Cei, J. M. (1987). ''Additional notes to ''Amphibians of Argentina'': an update, 1980-1986.'' Monitore Zoologico Italiano. Nuova Serie, Supplemento. Firenze, 21, 209-272.

Cochran, D. M. (1955). ''Frogs of southeastern Brazil.'' Bulletin of the U.S. National Museum, 206, 1-423.

Duellman, W.E., and Lizana, M. (1994). ''Biology of a sit-and-wait predator, the leptodactylid frog Ceratophrys cornuta.'' Herpetologica, 50, 51-64.

Gambarotta, J. C., Saralegui, A. and Gonzalez, E. M. (1999). ''Vertebrados tetrapodos del Refugio de Fauna Laguna de Castillos, Departamento de Rocha.'' Relavamientos de Biodiversidad, 3, 1-31.

Günther, A. (1859). Catalogue of the Batrachia Salientia in the collection of the British Museum. Taylor and Francis, London.

Hornegger, R. E., Schneider, C., and Zimmerman, E. (1985). ''Notizen zur Aufzucht von Schmuckhornfroeschen.'' Salamandra, 21(1), 70-80.

Lavilla, E. O., and Cei, J. M. (2001). Amphibians of Argentina, A Second Update, 1987-2000. Museo Regionale di Scienze Naturali, Torino.

Maneyro, R., and Langone, J. A. (2001). ''Categorización de los anfibios del Uruguay.'' Cuadernos de Herpetología, 15(2), 107-118.

Natale, G. S., Alcalde, L., Herrera, R., Cajade, R., Schaefer, E. F., Marangoni, F., and Trudeau, V. L. (2010). ''Underwater acoustic communication in the macrophagic carnivorous larvae of Ceratophrys ornata (Anura: Ceratophryidae).'' Acta Zoologica, published online before print, February 26, 2010, (doi: 10.1111/j.1463-).

Schmid, M., Haaf, T., and Schempp, W. (1985). ''Chromosome banding in Amphibia. IX. The polyploid karyotypes of Odontophrynus americanus and Ceratophrys ornata (Anura, Leptodactylidae).'' Chromosoma, 91, 172-184.



Written by Franziska Sandmeier (franturtle AT yahoo.com), UC Berkeley
First submitted 2001-03-12
Edited by Kellie Whittaker (2016-06-29)

Species Account Citation: AmphibiaWeb 2016 Ceratophrys ornata: Bell's Horned Frog <http://amphibiaweb.org/species/5723> University of California, Berkeley, CA, USA. Accessed Oct 21, 2017.



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Citation: AmphibiaWeb. 2017. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Oct 2017.

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