The boar Ysgithrwyn x Fenris

 I'm reading a book about Arthur, and I see many parallels between the Welsh hunting of boar Ysgithrwyn (meaning?) and the binding of Fenrir in Norse myths.
Ysgithrwyn had a comb and scissor between his ears, and must be hunted only by certain men, bound by certain specific chain, and his tusks were terrible.
Could be a relict of an older Celtic myth, akin to Fenrir binding and Lars Porsena defeating?

Joao SL