PALAVRAS-CHAVE Morfofisiologia Ultrassonografia Serpentes KEYWORDS Morphophysiology Ultrasonography Snakes RESUMO: O interesse econômico tem levado à melhoria das técnicas de manejo das criações de serpentes em cativeiro. A demanda por indivíduos regularizados, para criação como animais de companhia, torna-se um desafio para o Médico Veterinário, que dispõe de poucas informações, quando comparadas à quantidade de dados existentes sobre a clínica e o manejo de animais de companhia. Existem diversos registros na literatura sobre a morfofisiologia de répteis; entretanto, há poucos relatos quanto à descrição de sua anatomia ultrassonográfica e, menos ainda, sobre serpentes. Dessa forma, com este artigo, pretende-se fornecer informações referentes à anatomia ultrassonográfica de jiboias (Boa constrictor), abordando tópicos sobre a morfofisiologia dos órgãos mais estudados do ponto de vista ultrassonográfico. A ultrassonografia caracteriza-se por ser uma técnica não invasiva valiosa e que fornece informações em tempo real sobre a morfofisiologia do órgão avaliado, mostrando-se vantajosa para o diagnóstico de gestação em serpentes, bem como para a avaliação das estruturas mais comumente estudadas, como sistema hepático, renal e genitourinário.

In mammals, the embryonic and fetal development of a species has evolved to maximize neonatal survival. In this study, we use a sample of 132 embryos/fetuses of wild lowland paca (Cuniculus paca), obtained over a period of 15 years through collaborative methods with local hunters in the Amazon to describe the intrauterine development of external and internal morphology of this Neotropical rodent. We also compare the newborn survival strategy in this species with other rodents. The crown-rump length (CRL) ranged between 0.6 and 24.6 cm. External features appeared in the following chronological order: limbs, eyelid buds, fusioned eyelids, genitalia, outer ear, tactile pelage, claws, skin, skin spots, covering pelage, teeth and open eyelids. Fetuses with CRL >19.5 cm presented all external features fully developed. The growth formula of fetal age was calculated as ∛W = 0.082 (t - 37.25), and age was accurately associated with CRL. We described the relationship between CRL and external and internal biometry. The liver declined in proportion within the internal cavity, while the relative volume of tubular gastrointestinal organs increased significantly along the embryo/fetal development. All organs, except the heart and the thymus, had similar relative volumes in advanced fetuses and adults. Our comparison of the intrauterine development in several rodent species indicates that the paca's reproductive strategy is comparable to species that are subject to low natural predation. Given that C. paca is perhaps the most hunted animal in Latin America, sustainable hunting throughout its range must take into account its relative reproductive performance.

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Studying the timing of the main events of embryonic and fetal development may clarify the strategies adopted by species to maximize neonatal survival and the consequences of these events for their life history. This study describes bone development during the fetal phase of the lowland paca (Cuniculus paca), comparing it with other precocial or altricial species, and its relationship with the species’ adaptive strategies. A total of 102 embryos/fetuses obtained over the course of 17 years through collaboration with local subsistence hunters in the Amazon were analyzed. Measurements of mineralization of the axial and appendicular skeletons were performed by ultrasonography using a 10–18‐MHz linear transducer. The chronological order of occurrence of mineralization in relation to the total dorsal length (TDL) was: skull (TDL = 4.1 cm); vertebral bodies (TDL = 4.6 cm); scapula, humerus, radius, ulna, ilium, ischium, femur, tibia, and fibula (TDL = 6.7 cm); ribs (TDL = 7.8 cm); clavicle (TDL = 8.5 cm); metacarpi/metatarsi (TDL = 11 cm); phalanges (TDL = 15 cm); tarsus (TDL = 18 cm); patella (TDL = 23 cm); and carpus (TDL = 27.2 cm). Secondary ossification centers first appeared in the femoral distal epiphysis (TDL = 16.6 cm) and tibial proximal epiphysis (TDL = 18.4 cm). Advanced fetuses (TDL > 30 cm, 97% gestational period) presented mineralization in all primary and most secondary centers. Compared to other species, paca neonates have a well‐developed skeletal system at birth, which is important for their independent postnatal locomotion. Our results may contribute to the monitoring of bone development in other wild species, helping us to understand their life history, and serving as parameters for comparisons between precocial and altricial mammals.

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With the advance of ultrasonic technology, new echocardiographic techniques have been developed and commonly used in veterinary medicine because it allows noninvasive, accurate, and reproducible evaluation. The aim of this study was evaluating the topography and echobiometric parameters of the heart in red-tailed boas raised in captivity. Biometric data were evaluated from the body and heart in 21 Boa constrictor constrictor (17 females and 4 males) using B-mode ultrasonography. The heart was in the first third of the total body length. The mean value of the snoutheart length corresponded to 29.15 ± 2.01% (mean ± standard deviation) of the body length. The statistical analysis showed a significant linear increase between body length/mass and biometric data (P < 0.01). The heart exhibited a topographical location compatible with arboreal/terrestrial habits.