Influência do controle vagal na resistência vascular pulmonar e desvio intracardíaco em Crotalus durissus (Squamata: Viperidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determinantes da resposta termofílica pós-prandial em Crotalus durissus terrificus (Squamata: Viperidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endoparasites infecting the semiaquatic coral snake Micrurus surinamensis (Squamata: Elapidae) in the southern amazonian region, Mato Grosso state, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Spatial Variation in Morphometry in Vanzosaura rubricauda (Squamata, Gymnophthalmidae) from Open Habitats of South America and its Environmental Correlates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gastrointestinal nematodes of the lizard Tropidurus hispidus (Squamata: Tropiduridae) from a semi-arid region of north-eastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Osteologia do neurocrânio de Iguana iguana iguana (Squamata: Iguanidae)

Skull represents the segment with conspicuous adaptations that, in lizards, may be conservative or promoted by selective pressures. The aim of assisting the morphological knowledge of reptiles, we provide a detailed description of the neurocranium of Iguana iguana iguana based on analysis of three dried adult skeletons. The skull of this species has basal characteristics in lizards without closure of cranial openings and general triangular shape. Bony structures that form the caudal base have many fusions, especially on the floor. In the caudal face the exoccipital and the opisthotic are fused and form the otooccipital, which contributes to the formation of the lateral part of the condyle. The central part is formed by the condyle supraocciopital. Fusions and skeletal structures in Iguana are similar to other lizards. There are no autopomorphies in the neurocranium for this species.

Occurrence of Strongyluris oscari (Nematoda; Heterakidae) in Enyalius bilineatus (Squamata: Leiosaurinae) from the Brazilian Atlantic Forest

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morphological and physiological specialization for digging in amphisbaenians, an ancient lineage of fossorial vertebrates

Amphisbaenians are legless reptiles that differ significantly from other vertebrate lineages. Most species dig underground galleries of similar diameter to that of the animal. We studied the muscle physiology and morphological attributes of digging effort in the Brazilian amphisbaenid Leposternon microcephalum (Squamata; Amphisbaenia), which burrows by compressing soil against the upper wall of the tunnel by means of upward strokes of the head. The individuals tested (<72 g) exerted forces on the soil of up to 24 N. These forces were possible because the fibres of the longissimus dorsi, the main muscle associated with burrowing, are highly pennated, thus increasing effective muscle cross-sectional area. The muscle is characterized by a metabolic transition along its length: proximal, medial and distal fibres are fast contracting and moderately oxidative, but fibres closer to the head are richer in citrate synthase and more aerobic in nature. Distal fibres, then, might be active mainly at the final step of the compression stroke, which requires more power. For animals greater than a given diameter, the work required to compress soil increases exponentially with body diameter. Leposternon microcephalum, and probably some other highly specialized amphisbaenids, are most likely constrained to small diameters and can increase muscle mass and effective muscle cross-sectional area by increasing body length, not body diameter.

New host records of Brazilian pentastomid species

Pentastomida é um táxon de organismos parasitas obrigatórios de sistema respiratório de vertebrados, principalmente répteis. Embora esse táxon seja muito importante para a compreensão da filogenia dos Metazoa, tem recebido pouca atenção. No Brasil, existem poucas coleções que abrigam espécies de pentastomídeos, quais sejam: a Coleção Helmintológica do Instituto Oswaldo Cruz (CHIOC), a Coleção de Invertebrados do Laboratório de Zoologia da Universidade Regional do Cariri (LAZ-URCA) e a Coleção Helmintológica do Laboratório de Parasitologia de Animais Silvestres (LAPAS). O presente trabalho descreve as espécies de pentastomídeos depositados na Coleção Helmintológia do LAPAS. O trato respiratório e as cavidades do corpo dos répteis foram removidos e analisados sob Microscópio Esteroscópico; quando encontrados os pentastomídeos, foram montados slides em meio Hoyer e identificados. Foram identificadas quatro espécies e outras três ficaram identificadas no nível de gênero, tendo sido registrados quatro novos hospedeiros para as espécies de pentastomídeos.

Hábitos alimentares de serpentes em Espigão do Oeste, Rondônia, Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

New primers for the amplification and sequencing of nuclear loci in a taxonomically wide set of reptiles and amphibians

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Répteis do Estado de São Paulo: conhecimento atual e perspectivas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Meta-Analysis of Predation Risk Effects on Pollinator Behaviour

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Energetic and physiological correlates of prey handling and ingestion in lizards and snakes

In this review, we summarize the energetic and physiological correlates of prey handling and ingestion in lizards and snakes. There were marked differences in the magnitude of aerobic metabolism during prey handling and ingestion between these two groups, although they show a similar pattern of variation as a function of relative prey mass. For lizards, the magnitude of aerobic metabolism during prey handling and ingestion also varied as a function of morphological specializations for a particular habitat, prey type, and behavior. For snakes, interspecific differences in aerobic metabolism during prey handling seem to be correlated with adaptations for prey capture (venom injection vs. constriction). During ingestion by snakes, differences in aerobic metabolism might be due to differences in cranial morphology, although allometric effects might be a potentially confounded effect. Anaerobic metabolism is used for prey handling and ingestion, but its relative contribution to total ATP production seems to be more pronounced in snakes than in lizards. The energetic costs of prey handling and ingestion are trivial for both groups and cannot be used to predict patterns of prey-size selection. For lizards, it seems that morphological and ecological factors set the constraints on prey handling and ingestion. For snakes, besides these two factors, the capacity of the cardio-respiratory system may also be an important factor constraining the capacity for prey handling and ingestion. © 2001 Elsevier B.V.

Morphology and histochemistry of the hyolingual apparatus in chameleons

We reexamined the morphological and functional properties of the hyoid, the tongue pad, and hyolingual musculature in chameleons. Dissections and histological sections indicated the presence of five distinctly individualized pairs of intrinsic tongue muscles. An analysis of the histochemical properties of the system revealed only two fiber types in the hyolingual muscles: fast glycolytic and fast oxidative glycolytic fibers. In accordance with this observation, motor-endplate staining showed that all endplates are of the en-plaque type. All muscles show relatively short fibers and large numbers of motor endplates, indicating a large potential for fine muscular control. The connective tissue sheet surrounding the entoglossal process contains elastin fibers at its periphery, allowing for elastic recoil of the hyolingual system after prey capture. The connective tissue sheets surrounding the m. accelerator and m. hyoglossus were examined under polarized light. The collagen fibers in the accelerator epimysium are configured in a crossed helical array that will facilitate limited muscle elongation. The microstructure of the tongue pad as revealed by SEM showed decreased adhesive properties, indicating a change in the prey prehension mechanics in chameleons compared to agamid or iguanid lizards. These findings provide the basis for further experimental analysis of the hyolingual system. © 2001 Wiley-Liss, Inc.