| evolutionary and developmental considerations of the diet and gut morphology in ceratophryid tadpoles (anura). | before metamorphosis, almost all anuran tadpoles are omnivores. larval carnivory occurs in some species and, it is associated with distinctive morphotypes. obligatory carnivorous tadpoles exhibit structural changes in the gastrointestinal tract compared to larvae that are predominately omnivores. the most distinctive feature of the anuran family ceratophyridae (three genera) overall is the enormous gape of adults. this feature increases their ability to capture extremely large and active prey. t ... | 2020 | 32723314 |
| ultrastructural changes in the follicular epithelium of ceratophrys cranwelli previtellogenic oocytes. | in this work we carried out ultrastructural, autoradiographic and biochemical analyses of the follicular epithelium during c. cranwelli previtellogenesis. this study revealed that the follicular epithelium in early previtellogenesis is constituted of a single layer of squamous homogeneous cells. during mid-previtellogenesis two types of cells develop: dark cells and clear cells. the follicular dark cells are actively involved in the synthesis of rna, which is transferred to the oocyte through th ... | 2007 | 17637109 |
| ontogenetic and structural variation of mineralizations and ossifications in the integument within ceratophryid frogs (anura, ceratophryidae). | ceratophryidae represent a monophyletic group of terrestrial and aquatic frogs inhabiting lowlands of south america where they are more diverse in semiarid environments of the chaco region. adult morphology of ceratophryids presents some features associated to terrestrial and fossorial life such as hyper-ossified skulls, spade feet for digging, among others. for anurans, different mineralized structures have been described in the integument as calcium reservoirs and related to the terrestrial li ... | 2012 | 23074148 |
| developmental origins of a novel gut morphology in frogs. | phenotypic variation is a prerequisite for evolution by natural selection, yet the processes that give rise to the novel morphologies upon which selection acts are poorly understood. we employed a chemical genetic screen to identify developmental changes capable of generating ecologically relevant morphological variation as observed among extant species. specifically, we assayed for exogenously applied small molecules capable of transforming the ancestral larval foregut of the herbivorous xenopu ... | 2013 | 23607305 |
| [bioacoustic of the advertisement call of ceratophrys cranwelli (anura: ceratophryidae)]. | the advertisement call plays an important role in the life history of anuran amphibians, mainly during the breeding season. call features represent an important character to discriminate species, and sound emissions are very effective to assure or reinforce genetic incompatibility, especially in the case of sibling species. since frogs are ectotherms, acoustic properties of their calls will vary with temperature. in this study, we described the advertisement call of c. cranwelli, quantifying the ... | 2013 | 23894980 |
| hormonal induction of spawning in 4 species of frogs by coinjection with a gonadotropin-releasing hormone agonist and a dopamine antagonist. | it is well known that many anurans do not reproduce easily in captivity. some methods are based on administration of mammalian hormones such as human chorionic gonadotropin, which are not effective in many frogs. there is a need for simple, cost-effective alternative techniques to induce spawning. | 2010 | 20398399 |
| effects of prey type on specific dynamic action, growth, and mass conversion efficiencies in the horned frog, ceratophrys cranwelli. | to be most energetically profitable, predators should ingest prey with the maximal nutritional benefit while minimizing the cost of processing. therefore, when determining the quality of prey items, both the cost of processing and nutritional content must be considered. specific dynamic action (sda), the increase in metabolic rate associated with feeding in animals, is a significant processing cost that represents the total cost of digestion and assimilation of nutrients from prey. we examined t ... | 2005 | 15985380 |
| a comparative sem-study on the teeth of 10 anuran species. | teeth of 10 anuran species have been investigated by means of scanning electron microscopy (sem). generally a great variability of the structure of dentine crowns and the zone of division was noted not only between the single species, but also within one species on the same dentigerous bone. 4 species (hyla cinerea, rana ridibunda, r. hosei, ptychadena spec.) mostly have more or less bladed bicuspid and clearly divided teeth corresponding to the "lissamphibia"-pattern. 2 species (xenopus laevis, ... | 1987 | 3674455 |
| the ontogeny of the olfactory system in ceratophryid frogs (anura, ceratophryidae). | the aquatic-to-terrestrial shift in the life cycle of most anurans suggests that the differences between the larval and adult morphology of the nose are required for sensory function in two media with different physical characteristics. however, a better controlled test of specialization to medium is to compare adult stages of terrestrial frogs with those that remain fully aquatic as adults. the ceratophryidae is a monophyletic group of neotropical frogs whose diversification from a common terre ... | 0 | 28948636 |
| chromosome pairing in female and male diploid and polyploid anurans (amphibia) from south america. | chromosome pairing in females and males of diploid (2n = 22) and tetraploid (2n = 44) odontophrynus americanus and diploid ceratophrys cranwelli (2n = 26) and tetraploid c. ornata (2n = 104) showed that diploid females formed more chiasmata per paired arm than diploid males and polyploids of both sexes. there was a reduction in the level of recombination in female polyploids by forming multivalents with terminal chiasmata. the reduction reflected a change in the genetic control of pairing in fem ... | 1983 | 6652566 |
| chromosome banding in amphibia. ix. the polyploid karyotypes of odontophrynus americanus and ceratophrys ornata (anura, leptodactylidae). | the somatic and meiotic chromosomes of the south american leptodactylid toads odontophrynus americanus, ceratophyrys ornata, and c. cranwelli were analysed both with conventional staining and differential banding techniques. the karyotypes of o. americanus were tetraploid; those of c. ornata octaploid. ceratophrys cranwelli is a diploid species whose karyotype displays great similarities with that of c. ornata. the high frequency of multivalent pairing configurations in the meioses of o. america ... | 1985 | 3979176 |
| description of the adult skeleton and developmental osteology of the hyperossified horned frog, ceratophrys cornuta (anura:leptodactylidae). | the adult skeleton and tadpole chondrocranium of the leptodactylid frog, ceratophrys cornuta (ceratophryinae), are described in detail, including the ontogenetic development of the chondrocranium and the ossification sequence of the skeleton. the chondrocranium of the carnivorous larvae is unique in lacking a frontoparietal fontanelle and possessing a complete dorsal roof of cartilage. furthermore, the chondrocranium is extremely robust, particularly those elements involved in the feeding mechan ... | 1997 | 9097467 |
| comparative study of vitellogenesis in the anuran amphibians ceratophrys cranwelli (leptodactilidae) and bufo arenarum (bufonidae). | the present study analyses, by transmission electron microscopy, vitellogenesis in two anuran amphibian families: leptodactilidae (ceratophrys cranwelli) and bufonidae (bufo arenarum). these differ in the type of stimulus that sets off their reproductive period, pluvial changes being the trigger in c. cranwelli and temperature increase in b. arenarum. we found that vitellogenesis follows an endocytic pathway that involves membranous structures (coated pits, coated vesicles, endosomes and multive ... | 1999 | 10216912 |
| ultrastructural characteristics of the follicle cell-oocyte interface in the oogenesis of ceratophrys cranwelli. | in this work we carried out an ultrastructural analysis of the cell interface between oocyte and follicle cells during the oogenesis of the amphibian ceratophrys cranwelli, which revealed a complex cell-cell interaction. in the early previtellogenic follicles, the plasma membrane of the follicle cells lies in close contact with the plasma membrane of the oocyte, with no interface between them. in the mid-previtellogenic follicles the follicle cells became more active and their cytoplasm has vesi ... | 2002 | 12056457 |
| epidemic nodular facial myxomatous dermatitis in juvenile cranwell's horned frogs ceratophrys cranwelli. | in 2017, approximately 40 out of 100 captive cranwell's horned frogs ceratophrys cranwelli from several facilities in japan exhibited protruding facial lesions. histopathological examination was performed on 6 specimens with such lesions randomly selected from 2 facilities. lesions consisted of scattered stellate to spindle-shaped cells without atypia in an abundant myxoid matrix and occasional lymphocytic infiltrates. maxillary bone was resorbed. no etiological organisms were detected using lig ... | 2019 | 31020948 |
| comparative and functional analysis of the digital mucus glands and secretions of tree frogs. | mucus and mucus glands are important features of the amphibian cutis. in tree frogs, the mucus glands and their secretions are crucial components of the adhesive digital pads of these animals. despite a variety of hypothesised functions of these components in tree frog attachment, the functional morphology of the digital mucus glands and the chemistry of the digital mucus are barely known. here, we use an interdisciplinary comparative approach to analyse these components, and discuss their roles ... | 2019 | 31210775 |
| bite force in the horned frog (ceratophrys cranwelli) with implications for extinct giant frogs. | of the nearly 6,800 extant frog species, most have weak jaws that play only a minor role in prey capture. south american horned frogs (ceratophrys) are a notable exception. aggressive and able to consume vertebrates their own size, these "hopping heads" use a vice-like grip of their jaws to restrain and immobilize prey. using a longitudinal experimental design, we quantified the ontogenetic profile of bite-force performance in post-metamorphic ceratophrys cranwelli. regression slopes indicate po ... | 2017 | 28931936 |