Creatures & Treasures offers two "reptile men"
Lizard like amphibious Sohleugir.
Snake like poisonous bite desert dwelling Sstoi?isslythi.
The amphibious bit of the EA text comes from the description of the Sohleugir. I'd suspect that the Sahaugin of AD&D may either share a common myth source, or one was "inspired" by the other. . .two ocean dwelling lizard looking people with aggression issues. (Neither of which are fish people, which would fit a scaly humanoid that lives in the water.)
So they are amphibious lizard men. . . .definitely not amphibians, none of which live in the ocean that I can think of, and they definitely have a tough scaly hide. . .then again, what Class and Order would you call a Chimera? Taxonomy gets a bit hazy in a fantasy setting.
The Sstoi?isslythi are bipeds, so they're mostly "snake like", since I'd call a snake with limbs a lizard.
Then again, as GM, you could easily just ignore the amphibious bit, and make the Sohleugir land creatures, if that's what you wanted. It doesn't seem to have any effect on stats. (Other than you can't drown one.)