SiFi said:
They says this is concept art of Bowser, and I replied this to them:
I think I read somewhere that Miyamoto intended for him to be an ox, then someone asked "why is an ox the leader of the turtle army" and so he was changed to a turtle with ox-like features. So I have no idea when this drawing could be from relative to any of that.
Get ready for an incoming wall of text...
From
Iwata Asks Nintendo DS Volume 8: Yoichi Kotabe:
[quote author=Shigeru Miyamoto]Originally, ever since we made Donkey Kong, on many occasions I had done rough sketches of Mario in pencil and then given them to an external illustrator to polish up. When we came out with Super Mario Bros., I was thinking about asking a professional manga artist or a well-known illustrator to do the art, but time was running out, so I drew the original art for the package myself.[/quote]
And that art is
So, the first design of Bowser came from Miyamoto himself:
Miyamoto: Bowser changed a lot, too. I'd been drawing Mario for quite a while, so there were a lot of things on how I wanted him to look like, but I hadn't drawn Bowser that much, so I couldn't get the lines to come together right. I like Toei Animation's work from around the time of Alakazam the Great, and the ox that appears in that...
Kotabe: Oh, I remember you talking about that.
Miyamoto: I told him how I liked that ox.
Kotabe: The ox king. Miyamoto-san liked that ox, and that was how he imagined Bowser. When you see the package art he drew, Bowser does look a bit like an ox. But after that, Takashi Tezuka said...
Miyamoto: He said it was a turtle.
Kotabe: I thought, "Oh, it's a turtle?"
Everyone: (laughs)
Miyamoto: I'd been drawing something completely incomprehensible-a turtle's body with an ox's head! (laughs) Through our discussions, his appearance eventually came together, though. Since Bowser was in the turtle family together with the Koopa Troopas, we began to see similar lines between the two, so we copied those as faithfully as possible and move on to the next illustration. I started congratulating myself, saying, "Wow, I can really make Bowser look cool now!"
But there's more to this story, as Tezuka's involvement in Bowser's redesign is actually acknowledged in the only sketch of said redesign that I could find (and that I'm spamming to death and beyond, since it has Morton, Wendy, Lemmy and Iggy two years before they were introduced...):
The caption pretty much says that the this version of Bowser's design was the result of a collaboration between Kotabe and Tezuka.
In any case, this was the final result of Bowser's redesign:
I'm pretty sure you already saw these images, as they were reused many times for Bowser's artwork images.
I don't know what to think about that image you posted, it's a bit suspicious, as all Bowser's artwork images we saw here have the spiked shell, just like Bowser's sprite in SMB and SMB: TLL.
I think we should first of all clarify what is the source of that image.
EDIT: ok, in the description the author is stated to be Miyamoto, I wonder what is the source, though, as it would be very interesting to know it.