Introduction to the Chondrostei

Two chondrostean lineages survive today: the sturgeons of Eurasia and North America, and the paddlefish (shown here) of North America and China. These two lineages have secondarily lost a number of actinopterygian traits: they lack scales on most of the body, have a cartilaginous skeleton, and have developed a shark-like, heterocercal tail and a rostrum extending past the mouth (and forming the long "paddle" of the paddlefish shown here). The lineage is thought to be quite ancient, but the fossil record of chondrosteans themselves is quite poor, since the skeleton is cartilage instead of bone. However, some bony relatives of the living chondrosteans, known as saurichthyids or "lizard fish," lived in the Triassic and early Jurassic.

Unfortunately, these odd and ancient fish are currently endangered, because of habitat degradation and, in the case of several sturgeon species, overfishing for their flesh and their eggs (caviar).

Visit the Sturgeon of the Hudson River Homepage for ecological and conservation information about sturgeon populations.