The news article in the OP calls this the fish equivalent of a liger. But while lions and tigers are in the same genus, American paddlefish and Russian sturgeon are in completely different families. So this is much more than merely the "fish equivalent of a liger"; it would be like if a cat and a hyena somehow proved capable of producing viable offspring.
EDIT: From the article above, here's a picture.
I'm no expert on actinopterygians, but a few features from both species are immediately obvious. It's got the paddle-shaped rostrum of a paddlefish, but also has the dorsal scutes of a sturgeon.
This is really crazy. The lineages separated in the lower Jurassic. In terms of evolutionary distance, that’s a bit like a hybrid between a human (say Donald Trump) and a platypus, or at least a kangaroo…