physostomi silurus glanis sheat fish Siluridae catfish Siluriformes wels silurids clade

Siluridae is a family of catfish (order Siluriformes). They are sometimes known as sheatfish, although that name may also be used more specifically for Silurus glanis, the wels catfish. There are about 100 living species of silurids. Although silurids occur across much of Europe and Asia, they are most diverse in southeast Asia, beyond which their diversity decreases in temperate east Asia, the Indian subcontinent, southwest Asia, and Europe. Silurids are apparently absent from much of central Asia. The family can be divided into two groups, a temperate Eurasian clade and a more diverse subtropical/tropical south and southeast Asian clade. These catfish do not have a spine before their dorsal fin, do not have an adipose fin, and the pelvic fins are either small or absent. The anal fin base is usually very long. The largest species in this family is Silurus glanis, the Wels Catfish.