Navegando por Palavras-chave "Corythomantis greeningi"

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    Head co-ossification, phragmosis and defence in the casque-headed tree frog Corythomantis greeningi
    (Cambridge Univ Press, 2005-01-01) Jared, Carlos [UNIFESP]; Antoniazzi, Marta Maria; Navas, Carlos Arturo; Katchburian, Eduardo [UNIFESP]; Freymüller-Haapalainen, Edna [UNIFESP]; Tambourgi, Denise Vilarinho; Rodrigues, Miguel Trefaut; Inst Butantan; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    Some anurans have a peculiar casqued head with the skin co-ossified with the underlying bones. This type of skull usually is associated with phragmosis, a protective behaviour in which the animal enters a hole and closes it with the head. Although co-ossification of the head in lissamphibians frequently has been associated with water economy, recent studies of Corythomantis greeningi, a casque-headed tree frog from semi-arid areas in north-eastern Brazil. suggest that cranial co-ossification contributes little to conservation of water in the frog. Instead. during phragmatic behaviour. the co-ossified head protects the animal against predators and indirectly enhances water balance. Thus, the primary role of co-ossification is defence, a hypothesis that is the focus of this study which describes die morphology of the head of C. greeningi with all emphasis on the co-ossification and the venom glands. We report on behavioural features and on the toxicity of the cutaneous secretion produced by the abundant venom glands that are associated with large spicules oil the skull.
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    Mineralized dermal layer of the Brazilian tree-frog Corythomantis greeningi
    (Wiley-Blackwell, 2001-04-01) Katchburian, E.; Antoniazzi, M. M.; Jared, C.; Faria, F. P.; Santos, H. S.; Freymuller, E.; Universidade Federal de São Paulo (UNIFESP); Inst Butantan; Universidade de São Paulo (USP)
    Some species of anuran amphibians possess a calcified dermal layer (the Eberth-Kastschenko layer) located between the stratum spongiosum and the stratum compactum. This layer consists of calcium phosphate deposits, proteoglycans, and glycosaminoglycans. Although regarded as a protective layer against desiccation, a calcium reservoir, or possibly a remnant of a dermal skeleton present in anuran ancestors, very little is known about its origin, structure, and function. Thus, we studied the structure and composition of the mineralized dermal layer of Corythomantis greeningi, a peculiar hylid from the Brazilian semiarid region (caatinga), using conventional and cryosubstitution methods combined with transmission, scanning, and analytical electron microscopy. Results show that the dermal layer consists of dense, closely juxtaposed, globular structures. Although the electron opacity of the globules was variable, depending on the type of preparation, crystal-like inclusions were present in all of them, as confirmed by dark field microscopy. Electron probe X-ray microanalysis showed calcium, phosphorus, and oxygen, and electron diffraction revealed a crystalline structure comparable to that of a hydroxyapatite. (C) 2001 Wiley-Liss, Inc.
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    Some aspects of the natural history of the casque-headed tree frog Corythomantis greeningi Boulenger (Hylidae)
    (Elsevier B.V., 1999-07-01) Jared, C.; Antoniazzi, M. M.; Katchburian, E.; Toledo, R. C.; Freymuller, E.; Inst Butantan; Universidade Federal de São Paulo (UNIFESP)
    Corythomantis greeningi, a casque-headed tree frog, was studied in the field and in captivity. This species belongs to a monotypic genus, and together with other species of anurans, possesses a differentiated head which is flat, very rough and presenting cranial co-ossification with the skin. These are characteristics that are usually associated with phragmotic behaviour which is supposed to have a role in water saving and protection against predators. Observations were focused on the characteristics of the species which make it adapted to life in the Brazilian semi-arid (caatinga). Data about the body and external anatomy of the head, integument morphology, life, reproduction, interest for sheltering and defense against desiccation is presented. Finally, it is proposed that adaptation of this species to the dry environment is probably the result of the synergism of a number of different strategies against water loss, including phragmosis. (C) 1999 Editions scientifiques et medicales Elsevier SAS.