This word appeared on the National Spelling Bee (US) today, and was (amazingly to me) missed. I'm well-familiar with the word as a species of fish from my interests in fisheries biology, but I've always assumed this word was fairly well-known to most since the sculpin is a favorite illustration in most books (especially children's' books) on ocean fishes. But what intrigued me most was their assertion, when asked, that the etymology of sculpin was of unknown origin. So I immediately took to searching and 'tis so! I'm incredulous that a word of such unusual character has an untraceable origin. I always assumed, since the fish in question is a bony creature with spindly spikes of bones emanating from it, most peculiarly around its head, that the name developed from the nick-name skull pin(s), since the head spikes are indeed reminiscent of a pin sticking in (or protruding out from) the skull. All I could find is a date of 1627. And an alternative spelling, skulpin, which I have seen from time to time over the years, and which causes me to wonder how they can validate the "c" spelling for the National Spelling Bee. In lieu of the "skull pin" nick-name theory, my other assumption had always been that it was from the Latin. Any ventured guesses on the origin of this word?

Webster Dictionary 1913

Scul"pin (?), n. [Written also skulpin.] (Zoöl.) (a) Any one of numerous species of marine cottoid fishes of the genus Cottus, or Acanthocottus, having a large head armed with sharp spines, and a broad mouth. They are generally mottled with yellow, brown, and black. Several species are found on the Atlantic coasts of Europe and America. (b) A large cottoid market fish of California (Scorpænichthys marmoratus); -- called also bighead, cabezon, scorpion, salpa. (c) The dragonet, or yellow sculpin, of Europe (Callionymus lura). &hand; The name is also applied to other related California species. Deep-water sculpin, the sea raven.

sculpin photo:
http://www.njscuba.com/images/njs/sculpin.jpg

sculpin illustration:
http://www.m-w.com/mw/art/sculpin.htm