Description: Corythomantis greeningi has an average snout-vent length of 73.0 mm and an average weight of 21.1 g in males. The entire body is rough, covered with warts, which are comprised of mucous and granular glands and contain white odorous secretions that may be toxic and effective against predators (Jared et al. 1995; Jared et al. 1999). This species is characterized by a cranial co-ossified dermis, and a flat head covered with tiny spicules, which contribute to minimizing water loss in an arid environment (Navas et al. 2002, Jared et al. 2005). C. greeningi has distinct occipital crests (Jared et al. 2005).
Coloration: The coloration of the species is sexually dimorphic where males and females exhibit variation in their dorsal skin coloring. The ground color in males varies from dark to light brown. Females are also often brown but distinguished from males by distinct dark patterns on the dorsum. Males are also identified by the presence of a white vocal sac (Jared et al. 1999).
Tadpole Morphology: From the dorsal view, C. greeningi tadpoles have oval bodies and are slightly depressed in profile. C. greeningi tadpoles have rounded snouts with dorsally oriented eyes, an oral disc with a complete uniserial marginal papillae, a single spiracle located at center and below the midline of the body, a scouring surface on the front of the upper sheath, and keratinized mouthparts that characterize them as type IV tadpoles (Juncá et al. 2008).
Tadpole Coloration: C. greeningi tadpoles are mottled black on their dorsal and lateral surfaces with a solid cream colored belly. Conspicuous dark brown intestines are seen both ventrally and laterally. The tails are more pigmented than their fins and the dorsal fin is more pigmented than the ventral fin. Their beaks are black (Juncá et al. 2008).
Variation: Females are larger than males and have an average snout-vent length of 86.5 mm and weight of 41.4 g (Jared et al. 1999).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Brazil
C. greeningi is endemic to semi-arid regions in northeastern Brazil (Caatinga) and is well adapted to dry environments (Jared et al. 2002; Jared et al. 2005).
This species can be found in a range of habitat types, from dry and moist savanna, to rock outcrops (Borges-Najosa and Skuk 2004).
Tadpoles have been observed in small ponds along the drying river bed or in lotic waters. These tadpoles are also frequently found clasping on the rocky river bed and swimming against the current. C. greeningi larvae exhibit the typical morphology of suctorial larvae living in fast-water habitats (Juncá et al. 2008).
Life History, Abundance, Activity, and Special Behaviors
During the dry season, C. greeningi remains mostly sedentary on tree branches or on rocks. C. greeningi are insectivores and are known to eat beetles (Jared et al. 1999).
During the reproductive season C. greeningi are often found near or in rock crevices, near where ephemeral pools form during heavy rainfall. Males are territorial and compete over ephemeral pools and lentic water ponds (Jared et al. 1999; Da Silva et al. 2010). The males often display territorial behavior by vocalizing within the ephemeral pool for several days. Males compete for territory by embracing each other until the weaker male is defeated (Jared et al. 1999).
Mating usually occurs out of the water. The male embraces the female in inguinal amplexus. After a period of time, the female will carry the male back to the water where the female releases her eggs (Jared et al. 1999). C. greeningi can lay clutches with over 700 eggs, which are adhered to a rock wall on the side of the water body (Da Silva et al. 2010; Jared et al. 1999). The eggs will remain there until the full development of the embryo (Jared et al. 1999). Before hatching, the eggs of C. greeningi are sometimes subject to predation by a species of ant, Solenopsis invicta (Da Silva et al. 2010).
Both males and females are capable of moving their head from side to side without distorting their body position (Jared et al. 1999).
The advertisement call is characterized by two parts. The first begins with a long series of low amplitude pulses that lack frequency modulation. The second is characterized by the amplitude decreasing after an amplitude peak (Juncá et al. 2008).
Analysis by Jared et al. (2015) found that Corythomantis greeningi was one of two Brazilian hylid frogs that posses bony spines, surrounded by toxic granular glands, that pierce through its skin on the head. The bony spines act as a delivery system for the toxic chemicals and thus the frog can be considered truly venomous. The venom of this frog was found to be more two times more lethal than Brazilian pitviper venom. The other frog species is Aparasphenodon brunoi, has a more lethal venom but produces less venom than Corythomantis greeningi. It is thought that both species can use their venom against potential predators.
Corythomantis greeningi also demonstrates phragmotic behavior, associated with its peculiar skull anatomy (Jared et al. 2005). This behavior is defined as an animal using part of its body to block the entrance of a burrow or a hole. If provoked or threatened, C. greeningi will often retreat into holes in trees, rocks, or bromeliads (Jared et al. 1999).
The head region of both sexes greatly resembles tree bark from Prosopis sp., commonly found in the areas that C. greeningi inhabit. Due to the cryptic appearance of the head region, phragmotic behavior is also advantageous in nature for predator avoidance and water retention (Jared et al. 1999).
Trends and Threats
There is currently no evidence that the populations of this species is declining. However, habitat loss due to agriculture of non-timber crops, aquaculture, livestock farming and grazing, and fire are major threats. Conservation efforts in the future should be directed toward land, water, and habitat protection and management (Borges-Najosa and Skuk 2004).
Possible reasons for amphibian decline
General habitat alteration and loss
Intensified agriculture or grazing
This species was first described by Boulenger (1896). It is in a monotypic genus (Frost 2011).
Borges-Najosa, D., and Skuk, G. (2004). Corythomantis greening. IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. www.iucncredlist.org.
Da Silva, G. L., dos Santos, E. M., and Gomes, J. P. (2010). ''Predation of eggs of Corythomantis greeningi Boulenger, 1896 (Anura, Hylidae) by Solenopsis invicta Buren (Formicidae: Myrmidinae) .'' Biotemas, 23, 153-156.
Frost, D. (2011). Amphibian Species of the World: an Online Reference. Version 5.5.
Jared, C., Antoniazzi, M. M., Katchburian, E., Toledo, R. C., and Freymüller, E. (1999). ''Some aspects of the natural history of the casque-headed tree frog Corythomantis greeningi Boulenger (Hylidae).'' Annales des Sciences Naturelles - Zoologie et Biologie Animale, 20(3), 105-115.
Jared, C., Antoniazzi, M. M., Navas, C. A., Katchburian, E., Freymüller, E., Tambourgi, D. V., and Rodrigues, M. T. (2005). ''Head co-ossification, phragmosis and defence in the casque-headed tree frog Corythomantis greeningi.'' Journal of Zoology, 265, 1-8.
Jared, C., Mailho-Fontana, P.L., Antoniazzi, M.M., Mendes, V.A., Barbaro, K.C., Rodrigues, M.T., Brodie, E.D Jr. (2015). ''Venomous Frogs Use Heads as Weapons.'' Current Biology, 25, 1-5.
Jared, C., Toledo, R. C., and Antoniazzi, M. M. (1995). ''A histological study of the integument of Corythomantis greeningi (Amphibia, Anura, Hylidae).'' Revista Brasileira de Biologia, 55(3), 509-515.
Juncá, F. A., Carneiro, M. C. L., and Rodrigues, N. N. (2008). '' Is a dwarf population of Corythomantis greeningi Boulenger, 1896 (Anura, Hylidae) a new species?'' Zootaxa, 1686, 48-56.
Navas, C., Jared, C., and Antoniazzi, M. M. (2002). ''Water economy in the casque-headed tree-frog Corythomantis greeningi (Hylidae): role of behaviour, skin, and skull skin co-ossification.'' Journal of Zoology, 257, 525–532.
Written by Lauren Cassidy, Colleen Kamoroff, and Corrina Kamoroff (cdkamoroff AT ucdavis.edu), UC Davis
First submitted 2011-04-20
Edited by Mingna (Vicky) Zhuang; Updated by Ann T. Chang (2015-08-12)
Species Account Citation: AmphibiaWeb 2015 Corythomantis greeningi <http://amphibiaweb.org/species/685> University of California, Berkeley, CA, USA. Accessed Dec 5, 2016.
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Citation: AmphibiaWeb. 2016. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 5 Dec 2016.
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