South American Spotted Grassfrog, Criolla Frog
Species Description: substitute name for Leptodactylus ocellatus: Lavilla EO, Langone JA, Caramaschi U, Heyer WR, de Sa RO. 2010.The identification of Rana ocellata Linnaeus, 1758. Nomenclatural impact on the species currently known as Leptodactylus ocellatus (Leptodactylildae) and Osteopilus brunneus (Gosse, 1851)(Hylidae). Zootaxa 2346:1-16.
© 2019 Dr. Peter Janzen (1 of 36)
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Argentina, Bolivia, Brazil, Paraguay, Uruguay
Life History, Abundance, Activity, and Special Behaviors
During the breeding time, i.e. from September to February, the males hide in aquatic vegetation and call with short monotonous notes at low pitch. Calls are louder and more frequent before rain, as the eggs are usually laid into seasonal ponds. Males beat glandular secretions of the female into a foamy mass while still on the female’s back, so the several thousand small black eggs are sheltered in a foam nest that will float on a water surface. The thumb spines or thorns in males are thought to give them a better grip during amplexus, when the males beat up the foam nest.
A usual nest is between 12 and 25 cm in diameter and often has a central hole of 4 to 8 cm width. This foam nest lowers the predation risk for eggs and larvae and keeps them moist in the seasonal ponds of tropical regions. In dry ponds shortly before heavy rainfalls, the foam nest is deposited, and eggs may even hatch in the nest and the larvae be released on the next rain, which will destroy the nest and fill the pond with water again. The larvae of L. ocellatus then have an evolutionary advantage over other larvae as they are further developed and may start metamorphosis earlier, before the pond may again fall dry. Seasonality of the ponds also ensures a lower predation risk for the larvae, because there are no fishes in seasonal ponds and other predators such as water insects and carnivorous tadpoles develop later after the filling of the pond.
Females are characterized by extended maternal care. They are often found sitting in the nest hole with the head poking out or beneath the nest, and they show threatening and biting behavior toward predators. Hatched larvae aggregate and move together in gregarious shoals, mostly accompanied by the mother in less than 1 m distance. Mothers will stay with the larvae both during the night and day and defend them against predation, especially birds such as the benteveo (Pitangus sulphuratus argentinus). On sight of a bird, the mother beats the water surface, so the larvae realize coming danger and rapidly hide beneath the mother.
Interestingly, the adult frogs may change the length of their guts in relation with feeding season and reproductive status. In L. ocellatus, the stomach of both sexes and the intestine in males is longer during the hot, high feeding season; the length of the female intestine is highest during the cold season and correlated with high estrogen levels, which occur shortly before spawning, so female intestine length is related to yolk production.
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
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Written by Joern Dietl, Susanne Fritz, Rebecca Kittel and Mirco Sole (mirco.sole AT uni-tuebingen.de), Zoological Institute, University of Tuebingen
First submitted 2010-02-01
Edited by Kellie Whittaker (2021-01-26)
Species Account Citation: AmphibiaWeb 2021 Leptodactylus latrans: South American Spotted Grassfrog <http://amphibiaweb.org/species/7436> University of California, Berkeley, CA, USA. Accessed Feb 28, 2021.
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Citation: AmphibiaWeb. 2021. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 28 Feb 2021.
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