The Polyodontinae family contains three known species:
- Polyodon spathula – American paddlefish
- Polyodontinae Crossopholis – extinct
- Psephurus gladius – Chinese paddlefish
Description and Biology (Family – Polyodontidae)
- Body fusiform, scarcely compressed
- Skin smooth, scaleless
- Snout lengthened and expanded into a long, thin, flat blade or spatula, the inner part formed by the produced nasal bones, the outer portion with a reticulate bony framework, the whole somewhat flexible
- Mouth broad and terminal, but overhung by the broad spatulate snout. Border of mouth formed by the premaxillaries, the maxillaries being obsolete; jays and palatines with numerous fine, decidous teeth in the young, scarcely evident in the adult; no tongue; spiracles present.
- Opercle rudimentary, its skin produced behind in a long, pointed flap; no pseudobranchiae; gill 4 1/2; gillrakers long, in a double series on each arch, the series divided by a broad membrane; gill-membranes connected, but free from the isthmus.
- A single broad branchiostegal ray; no barbels; nostrils at the base of the blade and double.
- A well-developed and continuous lateral line, its lower margin with short branches; dorsal fin placed posteriorly, of soft rays only; anal fin similar, somewhat more posterior.
- Tail heterocercal, the lower lobe, however, well-developed, the tail being thus nearly equally forked; sides of the upper caudal lobe armed with small, rhombic plates; pectoral fins moderate, placed low; ventrals many-rayed, abdominal.
- Air-bladder cellular, not bifid; pyloric coeca a short, broad, branching, leaf-like organ; intestine with a spiral valve; skeleton chiefly cartilaginous. (Jordan and Evermann, 1908)
Habitat and Range (American Paddlefish)
- All over the Mississippi valley, Texas and Louisiana, Minnesota and Wisconsin, east to Virginia, and west to South Dakota and Montana.
Market Forms
- Paddlefish are prized for both their meat and roe which has lead to overfishing. The IUCN has listed Polyodon spathula (American paddlefish) as “vulnerable”, and Psephurus gladius (Chinese paddlefish) as “critically endangered”.
Jordan, David Starr, and Evermann, Barton Warren. (1908). The nature library (Vol. 5, Fishes). New York: Doubleday, Page and Company.