Rhinelepini - Appearance and Anatomy

Appearance and Anatomy

Rhinelepini species are generally medium to large-sized Loricariids. Rhinelepini species are unique among Loricariidae for having a normal, circular iris as opposed to the bilobed, omega iris. These species end to have relatively thick armor plates on their bodies. In Iquitos, Peru, Pseudorinelepis genibarbis is known as carachama sin costilla, which actually means "Loricariid without ribs"; this refers to the trait that it shares with other Rhinelepini catfish; members of this tribe do not have ribs past the sixth vertebra.

One of the characters that binds this group together is a large U-shaped diverticulum of the digestive tract; this is always filled with air. The first part of the diverticulum is modified from the esophagus and consists of thick musculature; this passes a short distance before reaching the second, main, U-shaped part of the diverticulum. In Rhinelepis and Pseudorinelepis, the diverticulum functions as an accessory respiratory organ. In Rhinelepis, the diverticulum is more attached to the abdominal wall and the interior of the diverticulum is more textured. In Pogonopoma, the diverticulum is similar to a swim bladder and may be used as a hydrostatic organ; the first part of the diverticulum is greatly reduced and the second part is larger and has a smooth interior surface and less vascularized.