On the homologies of the skeletal components of catfish (Teleostei : Siluriformes) suspensorium

There has been much controversy concerning the identity of the components of the suspensorium in Siluriformes (catfishes). This confusion has implications not only for comparative morphology, but also for phylogenetic studies. The identity of the suspensorium components in catfish is reviewed here on the basis of: 1) dissections of numerous catfishes, including members of the most primitive group (Diplomystidae), and morphological descriptions in the literature; 2) developmental and paleontological data available; 3) functional morphology; and 4) comparisons with other member of the Ostariophysi, as well as with other teleosts. Our observations and comparisons indicate that catfish suspensorium consists of: 1) a hyomandibula+metapterygoid compound, which corresponds to the hyomandibula plus metapterygoid of other teleosts; 2) a symplectic+quadrate compound, which corresponds to the symplectic+quadrate of other teleosts; 3) an ectopterygoid+ectopterygoid compound, which corresponds to the entopterygoid plus ectopterygoid of other teleost. The small bones present in several catfishes between the anterior portions of the pars quadrata, the palatine, and the ethmoideal region are considered to be sesamoid ossifications.