Nature abhors a vacuum, but nature bloody loves a crab.
You see, there's this thing called "convergent evolution", in which two entirely separate species end up evolving into very, very similar-looking (but unrelated!) forms. The most famous and eminently meme-able example of this phenomenon is carcinisation — multiple crustacean species evolving into crab, or crab-adjacent, forms. It is the evolutionary singularity. Nature loves a crab.
This becomes relevant to Nintendo games thanks to newly-announced Scarlet & Violet Pokémon Wiglett, who resembles nothing more than a long, pale Diglett. We all assumed that Wiglett was therefore a Paldean regional form, because... well... that's been Game Freak's whole schtick for some time now, hasn't it? But no. Wiglett, according to Pokémon Scientists, is an entirely separate creature. So, wait, why does he look like Diglett, then? Have the Pokémon designers really run out of shapes already?
Convergent evolution is here to explain everything, friends. Reddit poster u/sdrey has made a small but helpful explainer of how convergent evolution works in the Pokéworld:
And here's what the official Pokémon website has to say:
"It’s said that Wiglett’s resemblance to Diglett might be a mere coincidence—a result of its adaptation to its environment. It may look like Diglett, but it’s actually a completely different species of Pokémon. Wiglett pokes a part of its body out of the sand to feed in the ocean. It’s still unclear what the rest of its body hidden in the sand is like or how long it might be."
Honestly, it's surprising this hasn't come up before. There are, after all, loads of similar-looking Pokémon that are apparently unrelated. Dragonite and Charizard; Audino and Indeedee; even the Paldean crab Klawf and the OG crabs Krabby and Kingler... or the dozens of Pokémon that look like off-brand Pikachus!
Now, can someone explain why a totally-unrelated-to-Diglett Pokémon was given a name almost identical to Diglett? Were the scientists feeling cheeky that day? Grrrr. I'm off to become crab.