Pterygoplichthyini
Pterygoplichthyini
Tribe of fishes
Pterygoplichthyini is a tribe of catfishes (order Siluriformes) of the family Loricariidae. It includes two genera, Pterygoplichthys and the currently undescribed genus referred to as the Hemiancistrus annectens group,[1] This group was earlier misspelled as Pterygoplichthini.[1] Pterygoplichthyines are known from nearly the entire range of loricariids except for the Guyanas and coastal streams in southeastern Brazil.[1] although later work by the same authority, and his co-authors, placed this group among the genus Hypostomus.[2]
Pterygoplichthyini is sister to the tribe Ancistrini, which shares the derived presence of an evertible patch of plates on the cheek.[1]
Pterygoplichthys and the H. annectens group differ most obviously in the number of dorsal fin rays (7 in the H. annectens group and 9+ in Pterygoplichthys).[1] The two genera are supported as sisters by only one derived characteristic: a modified stomach that is attached to the abdominal wall by a net of connective tissue.[1]
This modified stomach allows these fish to breathe air. The stomach is vascularized. A white net of connective tissue surrounds the organ, leaving a circular area in the middle of the stomach free; this connective tissue firmly holds the stomach to the body wall and is better developed in adults. It may also function as a hydrostatic organ, allowing the fish to remain buoyant midwater.[3]