I like turtles! or is it tortoises?

[Calilasseia]

@boomer47

"Well, actually, there’s a meaningful difference between tortoises and other turtles . All tortoises are in fact turtles—that is, they belong to the order Testudines or Chelonia, reptiles having bodies encased in a bony shell—but not all turtles are tortoises . If tortoises are turtles , why not just call all turtlelike creatures " turtle “?”

When I was taking biology classes between the ages of 11 and 16 here in the UK, the various species were distinguished as follows:

[1] Tortoise: exclusively terrestrial members of the Chelonia, with toed feet;

[2] Terrapin: partially aquatic members of the Chelonia, with toed feet, but restricted to freshwater habitats;

[3] Turtle: primarily aquatic members of the Chelonia, with flippers, found in marine habitats.

I’m unaware of the discovery of any species that do not fit neatly into those categories, either living of fossil. Though if someone points me at the relevant scientific papers, I’ll update the database accordingly.