Acipenseridae
by A. N. Svetovidov
Body elongate, its axis turned up to support upper lobe of tail; snout projecting beyond mouth, somewhat sub-conical to flat and elongate; jaws protractile, without teeth; mouth transverse, semicircular or crescentic, lips fleshy, 4 barbels in a row in front. A single dorsal fin, set far back on body, as also pelvic fins; first pectoral finray spinous; anal fin below hind part of dorsal fin; caudal fin heterocercal. Five rows of bony scutes or bucklers along body (dorsal and paired laterals and ventrals) and usually minute grains, or sometimes small bony plates, between rows of scutes; head covered with bony shields.
Freshwater and anadromous, when in sea mainly in brackish waters and near shores (especially juveniles); bottom-living or midwater pelagic; mostly solitary, but in small swarms during spawning runs or at places of hibernation; very valuable food fishes, both for flesh and for eggs (caviar). Feeding on bottom invertebrates (molluscs, crustaceans, polychaete worms) and small fishes. Spawning usually in spring or early summer in rivers in running water with suspended mud over stones, pebbles or gravel, to which the eggs adhere.
Genera 4; in Clofnam area 2.
Recent revisions: Berg (1948, 1962), Magnin (1963, 1964).