Antillean manatee (Trichechus manatus manatus Linnaeus, 1758) Tongue Morphology and Adaptive Herbivorous Implications.

Morphological study of the tongue is an interesting way of understanding evolutionary processes associated with feeding habits. Therefore, the aim of the present study was to describe the tongue morphology of the Antillean manatee and to understand possible morphological relationships with its way of capturing food. Macroscopic dissections and light and scanning electron microscopy analyses of seven manatee tongues were performed. The tongue in Antillean manatees is a muscular and robust organ, divided into apex, body, and root. It is firmly adhered to the floor of the oral cavity. Lingual papillae were distributed over the entire tongue surface. They were identified as filiform papillae concentrated in the apex. Fungiform papillae were present on the apex and lateral regions. Foliate papillae were located on the dorsolateral portion of the root. Lentiform papillae were located across the dorsal tongue surface. The mucosa was lined by a keratinized stratified squamous epithelium presenting compound tubuloacinar glands and taste buds in the foliate papillae. The tongue of the Antillean manatee is similar to other Sirenia species, both of which share a completely herbivorous diet.

Oropharyngeal cavity floor morphology in Eretmochelys imbricata (Testudines: Cheloniidae) hatchlings and evolutionary implications.

Morphological studies of the oropharyngeal cavity of chelonians have become an interesting tool in the understanding of evolutionary processes associated with feeding habits in aquatic animals and the transition from aquatic to terrestrial forms. In this context, the aim of the present study was to describe the oropharyngeal cavity floor morphology of hawksbill sea turtle (Eretmochelys imbricata) hatchlings. Ten dead hatchlings of undefined sex were obtained from nests hatched on the coast of the state of Rio Grande do Norte, Brazil. The heads of each specimen were fixed, dissected, and analyzed at the macroscopic and microscopic levels. The oropharyngeal cavity floor of the hawksbill sea turtle hatchlings is formed by the tongue, pharynx, floor muscles, and hyolingual skeleton, delimited in the rostral and lateral directions by a keratinized beak, called the rhamphotheca, and in the caudal region at the limit between the pharynx and the esophagus. The tongue muscles and the muscles that support the floor of the oral cavity comprise the following: m. hypoglossohyoideus, m. hypoglossoglossus, m. hyoglossus, m. genioglossus, m. constrictor laryngis, m. geniohyoideus pars lateralis, and m. intermandibularis. The oropharyngeal cavity floor mucosa is formed by keratinized stratified squamous epithelium and the lamina propria is formed by loose connective tissue. The floor mucosa is devoid of taste buds. We believe that the basic oropharyngeal cavity floor characteristics in hawksbill sea turtle hatchlings may comprise indications that these animals are plesiomorphic and that semiaquatic and terrestrial turtles may have undergone adaptations to feed out of water.

Morphological characterization of the digestive tube of hawksbill sea turtle (Eretmochelys imbricata) hatchlings.

Morphological studies concerning the digestive system can further information on animal diets, thus aiding in the understanding of feeding behavior. Given the scarcity of information on sea turtle digestive system morphology, the aim of the present study was to describe the digestive tube (DT) morphology of Eretmochelys imbricata hatchlings to further understand the diet of these individuals in the wild. DT samples from 10 stillborn turtles (undefined sex) were analyzed at the macro and microscopic levels. The esophagus, stomach, small intestine (SI), and large intestine (LI) are described. Histologically, the DT is formed by four tunics, the mucosa, submucosa, muscular, and adventitia or serosa. The esophagus is lined by keratinized stratified squamous epithelium, while the remainder of the DT is lined by a simple columnar epithelium. The esophagus mucosa is marked by conical, pointed papillae. The stomach comprises three regions, the cardiac, fundic, and pyloric and is covered by neutral mucous granular cells. The intestinal mucosa presents absorptive cells with microvilli, neutral and acidic goblet cells, and mucosa-associated lymphoid tissue. The SI is significantly longer than the LI (p value = 0.006841). These morphological findings are strong indications of adaptations to a carnivorous diet in this hawksbill turtle age group.

Pyrethroid insecticides along the Southwestern Atlantic coast: Guiana dolphin (Sotalia guianensis) as a bioindicator.

The presence of pyrethroid compounds in hepatic tissue of Guiana dolphins (Sotalia guianensis) is reported for the first time. Twelve pyrethroids were determined in 50 animals from eight locations of the Brazilian coast. The highest average concentration of total pyrethroids (∑PYR) was 1166 ng.g-1 lw, with values ranging from 148 to 5918 ng.g-1 lw, in Ilha Grande Bay, Rio de Janeiro State, while the Espírito Santo State had the highest median, 568 ng.g-1 lw. Permethrin was the predominant compound in most areas, contributing for 42% to 81% of the ∑PYR, whereas cypermethrin was the most abundant compound in Guanabara and Sepetiba bays (79% and 81%, respectively), both located in Rio de Janeiro State. Biological factors were not correlated with pyrethroids concentration. Tetramethrin and es/fenvalerate compounds were negatively correlated to the age, suggesting degradation/metabolization capacity in these animals that increases throughout life. Despite being metabolized and excreted, the wide use of these pollutants is reflected in relevant concentrations found in Guiana dolphins. This is the first study evaluating pyrethroids in a representative number of hepatic samples and covering >2600 km of coast. The overall lack of information on pyrethroids in cetaceans highlights the importance of understanding the profile and distribution of these pollutants in dolphins which exclusively inhabit the Southwestern Atlantic coast.

Angioarchitecture of collateral arteries of the aortic arch of Antillean manatee (Trichechus manatus manatus Linnaeus, 1758).

The aortic arrangement is an important structure associated with the maintenance of homeostasis. Based on this information, this study was conducted to describe the collateral arteries of the aortic arch of Antillean manatee and define the standard model for the species. Three specimens, an adult male, adult female and a male neonate, all strandings on the coast of the state of Rio Grande do Norte, Brazil, were used. The study was performed in the Laboratory of Morphophysiology of Vertebrates of the Federal University of Rio Grande do Norte, where in situ photographs were taken to demonstrate their topography. Subsequently, their hearts were removed and fixed in 10% formaldehyde and after 72 hr were dissected and analysed, obtaining schematic drawings and photographs of the vascular arrangement. The aortic arch was represented by three collateral arteries identified as the brachiocephalic trunk, left common carotid artery and left subclavian artery. This arrangement was similar to that found for other sirenians, and yet, for other mammals like hooded seal, murine, margarita island capuchin, black-handed tamarin, Mongolian gerbil and human. The morphological similarity presented in this study with different species of mammals, including humans, may contribute valuable information from an evolutionary point of view.

Arthritis in a glyptodont (Mammalia, Xenarthra, Cingulata).

Arthritic lesions have been frequently diagnosed in the fossil record, with spondyloarthropathy (a type of erosive and pan-mammalian arthritis) being one of the most common types described to date for mammals, though not restricted to this group. Here, we identify spondyloarthropathy in fossil bones from the late Pleistocene in Brazil assignable to a large glyptodont individual. Bone erosions in the peripheral joints (viz., the ulna, radius, left femur and tibiae-fibulae) associated with osteosclerosis allow the diagnosis of spondyloarthropathy. The presence of osteophytes in seven bones of the forelimbs (viz., the ulna and radius) and hind limbs (viz., the tibiae-fibulae, left femur and patellae) and a subchondral cyst in one element (viz., the left femur) indicate secondary osteoarthritis. A calcified deposition on the articular surface of the left patella indicates the presence of calcium pyrophosphate deposition disease, which, like the observed osteoarthritic alterations, likely represents a complication of spondyloarthropathy. This is the first report of spondyloarthropathy for xenarthrans.