Fossil evidence suggests that scent glands are basal features of Testudines. However, we know little about the structure of these glands in the Brazilian Kinosternidae. In this study, we described the macroscopic anatomy, histology, and histochemistry of the scent glands of three males and three females of Kinosternon scorpioides scorpioides from the Marajó mesoregion, Pará State, Brazil. In all of the specimens analyzed, regardless of sex, we found four scent glands, including two axillary and two inguinal glands that were structurally similar to each other. Each gland consisted of a single holocrine secretory lobule, a large lumen surrounded by relatively thin glandular secretory epithelium, an adjacent narrow layer of loose connective tissue, and a thick layer of skeletal striated muscle tissue surrounded by a serous tunic. The secretory epithelium produced a characteristic malodorous yellowish substance that was passed via a single duct through a bone channel in the bridge connecting the carapace to the plastron and excreted through an outer pore in the plate of each respective gland. Histologically, the secretory epithelium presented cells with two types of secretory vacuoles. Type 1 vacuoles stained red were the largest and most frequently found, and stained positively with Periodic acid-Schiff (PAS), suggesting they contained glycoproteic complexes. Type 2 vacuoles were translucent, smaller in size and fewer in number, and negative for PAS staining. Because they are very primitive structures, scent glands must play important roles in the lives of chelonians, but their real function remains unknown. Several hypotheses suggest that they can act as protection against ectoparasites, as a repellent of predators, in addition to attracting mates and eliciting other pheromonal responses. In this study, all animals reacted by exuding malodorous substances when handled, as a form of defense. However, these are just assumptions that need to be clarified with additional studies on animal behavior.

The genus Cotylophoron belongs to the Paramphistomidae family and its definitive hosts are ruminants in general. This work describes the presence of a new species of the gender, a parasite in the rumen and reticulum of Bubalus bubalis, on Marajó Island in the Eastern Brazilian Amazon, using of light microscopy, scanning electronic microscopy and molecular biology techniques. One hundred and ten animals were analyzed, of which 4.54% were parasitized by flukes in their adult forms. The helminths were found fixed to the ruminal mucosa and present Liorchis-type pharynx, Cotylophoron-type genital sucker, oblique testicles larger than the ovary, uterus in rings full of eggs and Cotylophoron-type acetabulum. These morphologic characters do not fit into any previously described species. Thus, it is proposed that this is a new species in the genus Cotylophoron. The present work expands the record of parasitism by helminths in Bubalus bubalis, this being the first record of trematoda from the genus Cotylophoron for this host in the Brazilian Amazon.

The Muscovy duck is a commercially important bird on the island of Marajó usually raised in a peculiar system that includes supplying fish viscera to the birds under semi-extensive farming conditions. This enables a risk of contamination and losses in the production of these birds, resulting from injuries caused by helminth infections, especially nematodes. The objective of this study was to evaluate the histopathological changes caused by nematodes of the genera: Eucoleus, Anisakis and Contracaecum. Thirty-three ducks with lesions in the esophagus and ventricle were analyzed. Histopathological exams showed a mild inflammatory infiltrate in the submucosa of the esophagus caused by the fixation of E. contortus and third stage larvae of Anisakis sp., and we recorded third stage larvae of Contracaecum sp. parasitizing the ventricle, this being the first record of this parasite in ducks in Brazil.

A macroscopic and microscopic study of the mandibular organ of the silky anteater (Cyclopes didactylus) was carried out. The organ extends from below the zygomatic bone line to the middle of the mandible body, between the skin and the masseter muscle, on both sides of the animal. It has an average length of 11.7 mm and a width of 6.3 mm. In the mesoscopic analysis, it was observed that the organ presents in yellowish color due to the high amount of sebaceous content. In the histological analysis, the mandibular organ was observed to be composed of innumerable alveoli of the specialized sebaceous gland, surrounded by a layer of adventitia tunica. Scanning electron microscopy (SEM), revealed an apparent alveolar division with what appeared to be a sulcus at its center. The information here presented regarding the constitution and location of this structure has not been previously explored for other species and differs with respect to other descriptions for anteaters. Based on the present study, it is suggested that the mandibular organ is involved in social interaction in this species.

As a member of the Mustelidae family, E. barbara has characteristics common to the family, including a slender body with a long tail (twothirds the size of its body) (