Morphological analysis of the digestive tract of Sphoeroides testudineus showed an esophagus with an anterior and a posterior portion, the abdominal pouch. No stomach was observed between the abdominal pouch and the intestine. The intestine was arranged in three segments and two loops, and the distal portion had the rectum opening into the anus. Histochemical analyses showed that the esophagus secreted acid mucosecretions, and that there was a qualitative increase in goblet cells from the proximal to distal area of the intestine. The rectum showed cells secreting acid and neutral mucus. Given these features, this species presents a morphology which creates a link between its ecology and behavior.

Aging is a biologic process characterized by progressive damage of structures and functions of organic systems. In gastrointestinal tract, it can involve enteric nervous system, which plays an important role in digestion and absorption of nutrients, causing hastening of intestinal transit thus reducing its absorptive function. Caloric restriction has been used in several studies with the intention of delaying deleterious effects of aging. This study aimed to evaluate the effects of caloric restriction on myenteric neurons of ileum by aging in rats. 30 Wistar rats were grouped as follows: GI (animals aged 6 months fed with normal diet), GII (animals aged 18 months fed with normal diet) and GIII (animals aged 18 months subject to 31% of caloric restriction). The rats of the GI group were euthanized at 6 months of age and after experimental period of 12 months animals of the group GII and GIII were euthanized, the ileum of all groups were collected, measured and processed by NADPH-dp and Acetylcholinesterase. Quantitative analysis of neurons revealed that aging promotes the increasing of myenteric neurons NADPH-dp and reduces Acetylcholinesterase neuronal population. However, in the cellular profile area, were not observed significant differences between the groups. The caloric restriction has been efficient and can be used preventively because it minimizes quantitative changes associated with aging on ileum myenteric plexuses.

Foram estudados corpúsculos de Herbst da mucosa palatina de avestruz em nível de microscopia de luz. Os corpúsculos compõem-se de uma cápsula externa, cápsula interna e axônio central. A cápsula externa apresentou numerosas lamelas, enquanto que a cápsula interna mostrou estrutura de folhas compactas. Os corpúsculos apresentaram formato ovalado ou circular e circundado por espessos feixes de fibras colágenas. Cada lamela estava composta de uma densa rede de fibras espessas. Os axônios terminais estavam situados ao longo do eixo, terminando em um bulbo terminal. As fibras da cápsula externa, coradas por Picrosirius e examinadas no microscópio óptico sob luz polarizada, revelou a presença de fibras colágenas do tipo I em verde e na região periférica observou-se grande quantidade de fibras colágenas do tipo III. Os corpúsculos apresentaram-se envoltos por células planas e envoltos por fibras colágenas.

The Southern‐fur‐seal belongs to the order Carnivora, suborder Pinnipedia, and Otariidae family. This species inhabits aquatic and terrestrial environments, thus presenting important morphophysiological adaptive changes, especially in the cardiac system. For this purpose, Southern‐fur‐seal (Arctocephalus australis) hearts were used from animals that died from natural causes. Gross morphology observations were supported by light, scanning and transmission electron microscopy. The heart was long and flat; it was lined by pericardium and partly covered by lungs. Structurally, atrium and ventricle muscle fibers exhibit typical features of cardiac fibers revealing myofibrils bundles, mitochondria, plate‐shaped junctions, anastomosis between myofibrils bundles, and electron‐dense granule natriuretic around the nucleus and mitochondria of atrium muscle cells. The Southern‐fur‐seal heart was structurally similar to other mammals; however, it presented morphological changes that assist in their adaptation to their environment.

Andrade, I.M., Guimarães, J.P., Rotundo, M.M., Mari, R.B. 2016. Effect of gonad maturation on the morphology of the digestive tract of the Whitemouth croaker Micropogonias furnieri (Desmarest, 1823) (Perciformes: Sciaenidae). -Acta Zoologica (Stockholm) 00: 000-000.Studies have shown the feeding diversity of teleostean fish, which is conditioned by environmental characteristics or the biology of the different species. Analysis on the morphology of the digestive system (DS) of fish made it possible for researchers to know the food regimen of several species at different stages of life. On the other hand, it is known that food habits may lead to morphological changes in the DS the same way that different food habits may be imposed by morphological limitations of this system. Among the species of greater commercial importance in Brazil, Micropogonias furnieri is highly representative of fish in south-eastern Brazil. Therefore, the objective of this study was to analyse the morphology of the DS of M. furnieri. Results on the morphology of the DS observed in this study were similar to the patterns determined for the morphology of teleostean fish. In this study, it was observed that the DS of the Whitemouth croaker is directly related with the shape of the peritoneal cavity; these fish showed oesophagus, stomach, pyloric caeca and intestines. The pyloric caeca showed morphological adaptations in relation to sexual maturation, with well-developed caeca found in sexually mature animals.

Stenella clymene is an endemic species of dolphin living in tropical regions in the Atlantic Ocean. Despite its wide distribution, there is still scarce information on Stenella clymene, including its reproductive biology. In this context, this work describes the morphology of the whole male reproductive tract of the Clymene dolphin. Five males (N = 5) were studied after stranding on the northeast coast of Brazil. The analysis was performed through the use of macroscopic techniques and light and scanning microscopy. The male reproductive system consists of large testes wrapped around the tunica albuginea and adhered to the epididymis; the testes are attached to the abdominal cavity by the mesorchium. The ductus deferens is convoluted in the proximal portion and rectilinear in the distal portion. The prostate was the only accessory gland found, which is submerged by the prostate compressor muscle and lined with a dense fibroelastic capsule. The penis is classified as fibroelastic, with a spiral sigmoid flexure associated with a large volume of muscle tissue. The penis is inserted into two vestigial bones or pelvic bones, which exhibit no connection with the spine. In conclusion, the macro‐ and microscopic conformation and other morphofunctional features of the male reproductive organs of Stenella clymene are in accord with the anatomy observed in other Cetartiodactyla.

The autoclaved diet did not alter the quantity of neurons, but increased their cell body area, suggesting changes similar to those observed in protein deficiency.

In most anatomical studies developed with mammals, the tongue is described as highly differentiated among different species. However, studies on the tongue of aquatic mammals are still limited as compared to those on terrestrial mammals. The aim of this study was to describe the tongue morphology of the Franciscana dolphin (Pontoporia blainvillei) using macroscopic observations, light, and scanning electron microscopy. Microscopically, the dorsal surface was covered by a keratinized stratified epithelium. Salivary gland acini were found on the middle and caudal third of the tongue. The dorsal surface was totally covered by filiform papillae with a connective tissue core and a connective tissue structure round in shape in the middle and caudal regions.