Figure 1
Lateral view of the head of S. fuscus: (A) mouth closed; (B) mouth open showing the teeth; (C) the first branchial arch showing the gill rakers; (D) the second branchial arch.
S. fuscus presents a wide but short tubular esophagus that runs from the posterior end of the pharynx to the anterior cardiac region of the stomach. The sac-like stomach is divided into the cardiac, fundic, and pyloric regions. The pyloric region extends towards the beginning of the intestinal tube. At the junction of the stomach with the intestine, there are three pyloric caeca. The intestine has anterior, medium, and posterior portions (Figure 2). Ventrally, the rectum ends at the anus situated in front of the anal fin.