Anatomy, histology and ultrastructure of the digestive tract in Andean fish (Trichomycterusbogotensis) and ecological implications

Trichomycterus bogotensis is one of the three species of fish that inhabit the Colombian Andes. However, several aspects of its basic biology, including its digestive system, are unknown. The morphology and histology of the digestive system are of great importance for understanding a species' feeding habits and food preferences. Thus, this study aimed to perform a morphological description of the digestive tract of T. bogotensis. The gastrointestinal tract of seven specimens was processed for paraffin histology, high-resolution optical microscopy, and transmission electron microscopy. Anatomically, T. bogotensis exhibits a terminal mouth with villiform teeth, a narrow esophagus, a large and muscular stomach, and a short intestine. Histology and ultrastructure revealed a tissue organization similar to that reported for other Silurids, composed of four layers: mucosal, submucosal, muscular, and serosa. The anatomical and histological characteristics suggest that T. bogotensis is a benthic species with a tendency to carnivory.