Aractosteus is the name of a genus first described in
Constantine Rafinesque, Ichthyologia Ohiensis, Natural History of the Fishes Inhabiting the River Ohio and Its Tributary Streams, W. G. Hunt, Lexington, Kentucky, 1820. Reprinted by Arno Press, New York, 1970.
On page 75 of his book named above, Rafinesque writes,
This is a formidable fish living in the Mississippi, principally in the lower parts, also in Lake Pontchartrain, the Mobile, Red River, &c. It has been seen sometimes in the lower parts of the Ohio. It reaches the length of eight to twelve feet, and preys upon all other fishes, even Gars and Alligators. Mr. John D. Clifford told me that he saw one of them fight with an alligator five feet long and succeed in devouring him, after cutting him in two in its powerful jaws.