[8][9] The oldest fossils of Saurichthys were recovered from the Wordie Creek Formation in East Greenland and are Griesbachian (Induan, Early Triassic) in age.

[11] The use of subgenera (Eosaurichthys, Costasaurichthys, Lepidosaurichthys, Saurorhynchus, Sinosaurichthys) in the literature reflects differences in morphology between species groups.

Historically, they have been seen as close relatives of the Acipenseriformes (which includes living sturgeon and paddlefish) as part of the Chondrostei, though this has been strongly questioned by modern studies, which suggests that it may lie outside the Actinopterygii crown group.

Some species were only a few decimetres long (e.g. Saurichthys minimahleri), while others could grow up to about 1.5 metres (4.9 ft) in length (specimen from the Middle Triassic of Turkey).

[15] Its jaws were extremely long, making up a third of the total body length, and ended in a sharp, beak-like tip.

[16] Large species of Saurichthys were apex predators among Triassic ray-finned fish, together with the marine Birgeria (Birgeriidae).

[18] Fossil evidence, in the form of a bolus (ball-shaped mass) of bones in the same strata, indicates that Saurichthys attacked marine reptiles such as the tanystropheid Langobardisaurus, or possibly scavenged their corpses.

[citation needed] A study on the gastrointestinal tract of Saurichthys found similarities with present-day sharks and rays, in particular the many windings in the spiral valve.

[22] This list includes species of Saurichthys that are generally considered valid (based on Romano et al.[8] and references cited below).