The dinosaurs in Season 6 evolved from the ones in Season 3?
 

Everyone knows about the classic Season 3 ep, "Turtles at the Earth's core" where the Turtles discover dinosaurs still alive deep under the Earth's crust.

In Season 6's, "Leonardo is Missing" they come across another group of dinosaurs underground, only this time they can speak and are intelligent. They tell the Turtles they lived deep within the Earth's core and escaped extinction millions of years ago. So basically the same place as the previous ones.

Were these dinosaurs evolved versions of the same dinosaurs from Season 3? Or did somehow these talking dinosaurs existed back then, the Turtles just didn't come across them?

I have always thought it as a continuity hiccup ever since it aired way back. It can be played with by fans who could theorize they were apart of the underground society but due to a alien meteorite gained hyper intelligence allowing them to walk upright and speak english.

The other dinosaurs are smaller aren't they? I don't recall but I'd think they're just two different dinosaurs that survived, just oen of them evolved and the others didn't.

Season 6 is one big continuity error. Examples: Baxter showing up w/o his AI-friend and any explanation of how he escaped limbo; Rat King's flute rematerializing only to never be seen again even though it was smashed to bits last time; Proffessor Sofo showing up for his second appearance in the '92 season when Donatello's graduation was slated for '94.

So, I call S6 the 'what if' season.

Baxter and Rat King weren't in Season 6. Baxter's ep was from Season 5 and Rat King goes from appearing in Season 5 (Donatello's Duplicate), to his next appearance in Season 7.

Oh. You're right. I guess my memory just really wants to blame a specific season when these continuity-burning eps are really just scattered.

1. It's easy to get a new flute. There's something called music stores, where you buy or steal instruments.
2. Proffessor Sofo probably mean that when the Earth had spinned faster and faster, they would go from 1990 to 1994 within the same day, Graduation Day! (even if I doubt anyone else used that counting). Proffessor Sofo could just blame it on mistake if someone asked why he meant the wrong year. Or just those who started studying there in 1990 would be completed in 1994.
3. The idea that he escaped any place doesn't contradict that he was sent there.

I thought the Season 6 dinosaurs were from the same place as the Season 3 ones when I heard them talking about being from the Earth's Core.

It can't be the same, unlsess Krang accidentally spilled out some mutagen into that cave during season 3. I go more for that most of the dinosaurs where just ordinary, except these.

The writers most likely forgot all about 'Turtles at the earthcore' when writing 'Leonardo missing'. The episode might not even exist to their acknowledgement.

I doubt it, many Season 5 and 6 episodes had callbacks to older episodes. The Polarisoids return and Shredder/The Turtles talk about being stuck inside his camera. Rex-1 returns and he and April recollect their adventure.

April's Aunt Agatha returns and the Turtles all remember her. The personality alterator returns in "Mr. Nice Guy" and the Turtles remember how it changed Leonardo's personality back in Season 4.

Why they would remember all that but not the dinosaurs would seem odd. Those talking dinosaurs could have been aliens, but they said they were in the Earth's core.

Perhaps the writers did remember the episode, but figured they'd missed a golden opportunity to have the dinosaurs at the earth's core be advanced, so maybe the writers were just hoping us kids had forgotten that episode and ignored it when writing "Leonardo is Missing".

Leonardo is Missing takes place during season 5, or right before "Rock Around the Block", since the Technodrome is still in the Arctic.

Actually, it was originally the season 6 premiere episode. For some odd reason they put it in the second disc of the DVD set.