Morphohistology of the digestive tract of the damsel fish Stegastes fuscus (Osteichthyes: Pomacentridae).

This study investigated the morphohistology of the digestive tract and the mean intestinal coefficient of the damsel fish Stegastes fuscus captured from the tidal pools of Northeastern Brazil. The wall of the digestive tract of S. fuscus is composed of the tunica mucosa, tunica muscularis, and tunica serosa. The esophagus is short with sphincter and thick distensible wall with longitudinally folded mucosa. Mucous glands are predominant, and the muscular layer of the esophagus presented striated fibers all along its extension. The transition region close to the stomach shows plain and striated muscular fibers. Between the stomach and intestine, there are three pyloric caeca. The intestine is long and thin with four folds around the stomach. The anterior intestine presents folds similar to those of pyloric caeca. The estimated mean intestinal coefficient and characteristics of the digestive system of S. fuscus present morphological adequacy for both herbivorous and omnivorous feeding habits.