Se presenta la descripción de la anatomía microscópica del sistema digestivo de Enteroctopus megalocyathus, observándose algunas diferencias entre este octópodo, y otras especies de Octopodidae descritas previamente. Estas diferencias están principalmente relacionadas con los tejidos que revisten el lumen de los órganos digestivos. Contrariamente a las descripciones de la mucosa de algunos octópodos, en E. megalocyathus el lumen del esófago, buche, estómago, intestino y ciego está revestido por un epitelio pseudoestratificado. Otro hallazgo notable es que en las glándulas salivales posteriores están presentes dos tipos celulares en el mismo adenómero tubular: las del tipo A, en la zona proximal del túbulo glandular, con células cilíndricas y células mucosas globulares; y las de tipo B en la zona distal, cilíndricas con citoplasma débilmente eosinofílico. La secreción de estas células se detectó con las técnicas de PAS y alcian blue a distintos pH. En los pulpos mantenidos sin alimento en el acuario durante dos días, la estructura histológica del epitelio del ciego, intestino y de la glándula digestiva mostró cambios histológicos con respecto a los de la mucosa de los pulpos procesados inmediatamente luego de su captura. En conjunto, estos resultados permitieron caracterizar histológicamente los órganos del sistema digestivo de E. megalocyathus en su hábitat natural y establecer observaciones preliminares respecto de la respuesta rápida (~2 días) a la privación de alimento, y brindó datos de base para futuros estudios que investiguen el impacto de cambios ambientales en el tracto digestivo.

A detailed description of the microanatomy of the digestive system of Enteroctopus megalocyathus is given, and this revealed some differences between this octopod species and other species of Octopodidae previously described. These differences are mainly related to tissues lining the lumen of digestive organs. Unlike descriptions in some octopods mucosa, in E. megalocyathus a pseudostratified epithelium is found covering the lumen of oesophagus, crop, stomach, intestine and caecum. Another major finding is that in the posterior salivary glands, two cell types are present in the same tubular adenomere; they do not constitute independent glandular tubules with only one type of glandular cells. The tubules of these glands are lined by two distinct epithelial cells, distributed from the distal to the proximal zones: type A, in the proximal zone of the glandular tubule, with cylindrical cells and globular mucous cells; and type B in the distal zone, cylindrical, with a weakly eosinophilic cytoplasm. The secretion of the cells was detected applying PAS and alcian blue at different pH. In the octopuses maintained without food in the aquarium for two days, histological structure of the epithelium of the caecum, intestine and digestive gland showed histological changes specially related with the mucosa. Taken together, the results allow to set the histological structure of the digestive tract of E. megalocyathus in their natural habitat and to provide preliminary evidence that this system responds rapidly (~2 days) to food deprivation, and give baseline data for future studies investigating the impact of environmental changes on the gut.

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.

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.

A detailed description of the morphology of the digestive organs of Enteroctopus megalocyathus (Gould, 1852) and Loligo sanpaulensis Brakoniecki, 1984 is given. The mandibles, the crop diverticulum, a doubly coiled caecum, the loop of the medium intestine and the appendages of the digestive gland are first described for E. megalocyathus. The most outstanding finding in L. sanpaulensis is the location of the single posterior salivary gland, wholly embedded in the digestive gland.