Not All Turtles Are Koopas Part 1
So many people believe all turtles in the Mario world are a variant of Koopa, and they are all one big species in general Something I even did in the past. However, this is wrong. Not every turtle in the Mario World is a Koopa, aka a NokoNoko in Japanese.
So, the confusion stems from the Koopa Troopas being called Koopas, while Bowser is known as King Koopa and the King of the Koopas at times. This is because Bowser's name in Japanese is Kuppa, while the Koopa Troopas are actually known as NokoNokos. Bowser's Japanese name Kuppa is also likely his species name as well, which differentiates him from the Koopas(NokoNokos).
So Koopa Troopas aka NokoNoko are one of many species of turtles which can comprise the Turtle Tribe. In the Super Mario Bros. manual they are stated to be "Soldier(s) of the Turtle Empire."
Then you have the other turtle members of the turtle tribe, Spikes in Super Mario Run description says the following about Spikes. "This hardworking turtle has a very small shell." And the Bad Ball Boy Constellation from Mario Party 9 says the following about Spikes. "A constellation that calls to mind a fiendish turtle who can spit spiked balls at his foes."
Spiny's Egg Description from the SMB Manuals says the following. "Eggs of the turtle Spiny, pet of Lakitu." And the Sharp Shell Constellation says it's "a constellation named after a turtle who hides beneath a spiky shell."
Buzzy Beetle's Super Mario Run's description says the following about them. "This black turtle is protected by a tough shell."
Notice how none of these descriptions said they are a Koopa or NokoNoko. But rather just said they are turtles. This is because to my knowledge all turtles in Mario's world are not intended to be various species of Koopas. But rather Koopas are various species of turtles.
However, there are some actual Koopa species/ relatives. I believe with part of the Koopa's Japanese name NokoNoko is used in a name, makes connect amongst these species. There is the Bombshell Koopa whose name is Nokobon in Japanese meaning Koopa Explosion.
There is the Snooza Koopa whose name in Japanese is Tamago Nokonoko, meaning Eggshell Koopa. This would make them an ocean based species of Koopas that converged with Sea Turtles. This is because we see Sea Turtles in the Kong Archipelago which don't look similar to Snooza Koopas.
Then you have the Snortoise from the Flower Kingdom, whose name is Suppoko meaning Softshell Koopa. This would make them the Softshell Turtle equivalent of the Koopas Species. Written by Eris the Lorekeeper
Part 2