Was any Pokémon ever confirmed to be the first designed?

Question

I know bulbasaur is the first in the dex, but I have also heard that venusaur was the first in the line to be designed (source) and I have heard that rhydon was the first Pokémon to be designed but I’m not sure if that is true. Either poliwag or Poliwhirl, I've heard, is satoshi tijiri’s favorite, and that was influenced by his frog catching childhood. Could this have swayed him to create a frog Pokémon first? Was it ever revealed what the world’s first designed Pokémon was?

Comments

I could’ve sworn I saw this on the cutting room floor but I can’t find it

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Also this question is asking simply if it has been confirmed, not which one it is. Although if it has been confirmed please tell me which one it was

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Here's the tcrf page that shows that Rhydon occupied the first internal entry https://tcrf.net/Pok%C3%A9mon_Red_and_Blue/Internal_Index_Number Note that this doesn't necessarily prove that it was definitively the first Pokémon programmed, much less the first design; as mentioned in the page, Pokémon could be retroactively added into an earlier position in the list, as seen with how the list contradicts statements from interviews that Mew was the last to be added. But it does lend credence to the idea that Rhydon was an early concept. If someone could find similar interviews that describe Rhydon as being the first, that would be much better evidence.

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According to Hexahedron's source, there's a frog-like MissingNo., Feeshy-Freggles. You should look into that!

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O: frog Missingno is my dream but why can’t I find info on said frog Missingno anywhere else? I can only find pics of the forms I already know existed, (kabutops fossil, areodactyl fossil, ghost, yellow, and normal. M’ is sort of one?) not the 100 other ones in that source