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.

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.

Colocolic Intussusception Associated with Octangium sp. (Digenea: Microscaphidiidae) in a Green Sea Turtle Chelonia mydas.

Reports of intussusception in sea turtles are generally linked to marine debris ingestion; therefore, only a few cases of the disease are associated with parasitic infestations. The objective of this study was to describe the necropsy findings of the first reported case of colocolic intussusception in a green sea turtle Chelonia mydas, associated with the helminth Octangium sp. A juvenile female green sea turtle, which was registered and rescued by the team from the Cetaceans Project of Costa Branca, State University of Rio Grande do Norte, was examined. The animal died 1 d after being treated and was immediately submitted for necropsy. Our findings indicated that parasitic infestation by Octangium sp. in the green sea turtle caused intussusception and consequently led to the animal's death. Early diagnosis and surgical correction are fundamental for a good prognosis and, consequently, for successful rehabilitation of marine species.

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.

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.

Diet and histological features of digestive tube from four discarded fish species by trawl bycatch in Northeastern Brazil / Dieta e características histológicas do tubo digestivo de quatro espécies de peixes descartadas pela pesca de arrasto no nordeste do Brasil

Abstract: Fish feeding habit associated to the morphology of their digestive tube can provide useful biological and ecological information. Between January and December 2012, we examined 16 fish species discarded by trawl in the Potiguar basin, northeastern Brazil, and classified them into four groups according to Alimentary Index - IAi. Our aims were to: (1) provide information on diet composition of one species represented by each group (Opisthonema oglinum, Conodon nobilis, Larimus breviceps and Sphoeroides testudineus), (2) examine the morphology of their digestive tube, and (3) associate ingested food items with the morphological features. Stomach contents were collected and classified according to IAi: main, accessory and secondary categories; fragments of esophagus, stomach, and small intestine were examined using paraffin section technique. Biometric data (total length-TL, standard length-SL and total weight-TW), stomach weight-SW, and gonadal weight-GW were recorded and applied in two indices: (1) the stomach Repletion Index - SRI (SRI = SW/TW × 100) and (2) the gonadosomatic index - GSI (GSI = GW/TW × 100) for the analyses of feeding and reproductive activities, respectively. The main food categories were (1) Teleostei for C. nobilis, (2) Crustacea for L. breviceps and O. oglinum, and (3) Mollusca for S. testudineus. The feeding activity was higher during the dry season, while the GSI was higher in the rainy season. The morphological analysis revealed a regular structure of the tissues analyzed. We highlight the presence of tubular gastric glands and strong muscular walls in the stomach (O. oglinum; L. breviceps); well-developed pyloric caecum in the intestine (O. oglinum; C. nobilis; L. breviceps); and presence of pseudo-stomach (S. testudineus). Our study confirms that the digestive tube of the examined species has morphological adequacy for carnivorous feeding habit, providing useful information on tissue structures associated to diet composition.

Resumo: O hábito alimentar de peixes associado à morfologia do tubo digestivo pode fornecer informações biológicas e ecológicas úteis. Entre janeiro e dezembro de 2012, examinamos 16 espécies de peixes descartadas por pesca de arrasto na Bacia Potiguar, nordeste do Brasil, e as classificamos em quatro grupos, de acordo com o Índice Alimentar-IAi. Nossos objetivos foram: (1) fornecer informações sobre a composição da dieta de uma espécie representante de cada grupo (Opisthonema oglinum, Conodon nobilis, Larimus breviceps e Sphoeroides testudineus), (2) examinar a morfologia de seu tubo digestivo e (3) associar os itens alimentares ingeridos com as características morfológicas descritas. O conteúdo estomacal foi coletado e classificado de acordo com o IAi nas categorias: principal, acessória e secundária; fragmentos de esôfago, estômago e intestino delgado foram examinados pela técnica de secção em parafina. Os dados biométricos (comprimento total-CT, comprimento padrão-CP e peso total-PT), peso do estômago-PE e peso gonadal-PG foram registrados e aplicados em dois índices: (1) Índice de Repleção Estomacal - IR (IR = PE / PT × 100) e (2) Índice Gonadossomático - IGS (IGS = PG / PT × 100) para análises de atividade alimentar e reprodutiva, respectivamente. As principais categorias alimentares foram: (1) Teleostei para C. nobilis, (2) Crustacea para L. breviceps e O. oglinum, e (3) Mollusca para S. testudineus. Maior atividade alimentar ocorreu durante a estação seca, e o IGS foi maior na estação chuvosa. O exame morfológico revelou estrutura regular dos tecidos analisados, destacando-se a presença de glândulas gástricas tubulares e camadas musculares espessas no estômago (O. oglinum; L. breviceps); cecos pilóricos bem desenvolvidos no intestino (O. oglinum; C. nobilis; L. breviceps); e presença de pseudoestômago (S. testudineus). Nosso estudo confirma que o tubo digestivo das espécies examinadas possui adequação morfológica ao hábito alimentar carnívoro e fornece informações úteis sobre as estruturas dos tecidos associados à composição da dieta.

First confirmed record of Feresa attenuata (Delphinidae) for the Northern Brazilian Coast / Primeiro registro confirmado de Feresa attenuata (Delphinidae) para o litoral norte do Brasil

In Brazil only one confirmed stranding is known from an emaciated specimen collected along the southeastern coast. The aim of this work is to report a recent record of a pygmy killer whale from the coast of Maranhão State, northern Brazil. On 22 October 2005, through regular surveys conducted by Projeto Cetáceos do Maranhão team, a beach-worn skull of a pygmy killer whale was found on the Mangue Seco beach, at Caju Island, Maranhão State. The specimen was identified through peculiar features, such as a short beak, 11 teeth per row in the maxile and the distance between the anterorbital notch and the end of the toothrow. This stranding suggests that pygmy killer whales may use oceanic waters close to Maranhão continental shelf. This is the second confirmed stranding of F. attenuata for the Brazilian Coast and the first along the northern coast. The present record increases our poor knowledge on the cetacean fauna of the northern Brazilian coast.

No Brasil somente um exemplar de Feresa attenuata foi coletado ao longo da costa sudeste. O objetivo deste trabalho é registrar o recente encalhe da orca-pigméia para a costa do Maranhão, litoral norte do Brasil. Em 22 de outubro de 2005, através de monitoramentos regulares conduzidos pelo Projeto Cetáceos do Maranhão, um crânio do exemplar de F. attenuata foi encontrado na praia do Mangue Seco, na Ilha do Caju, Estado do Maranhão, Brasil. O espécime foi identificado através de características peculiares, como o rostro curto, 11 pares de dentes na maxila e pela distancia entre o anterorbital e o término dos alvéolos dentares. Este encalhe sugere que a orca-pigméia pode usar águas oceânicas próximas à plataforma continental do Maranhão. Este é o segundo registro de encalhe confirmado para F. attenuata para a costa brasileira e o primeiro para a costa norte. O presente estudo contribui com o pouco conhecimento sobre os cetáceos na costa norte do Brasil.