Anatomy of the Stomach in Three Species of Potoroinae (Marsupialia: Macropodidae).

Abstract

Stomachs of Potorous tridactylus, Bettongia lesueur and Aepyprymnus rufescens were dissected in situ. The general organization in all three species is very similar. The oesophagus opens into the tubiform fore stomach near its caudal end. The sacciform fore stomach region lies to the left of the abdomen; in adult animals it contains about 75% of the total gastric volume. Taeniae, haustra, and semilunar folds differentiate the wall of the sacciform fore stomach, but are absent from the tubiform fore stomach. Aborally the tubiform fore stomach is followed by the hind stomach, which is lined with fundic and pyloric glands. Both fore stomach regions are covered with cardiac mucosa. The potoroine stomach is different from the macropodine type, which has a small sacciform fore stomach and a long tubiform fore stomach, both with taeniae, haustra, and semilunar folds. The differences of the gastric anatomy in relation to differences in food and in biotopes are discussed, as well as the possible evolution of both types of macropodid stomachs.