UPDATE 2-NYMEX confirms oil traded once at $100/barrel

(Updates with trader comment, background, adds byline)

By Robert Campbell

NEW YORK Jan 2 (Reuters) - U.S. crude oil futures traded once at $100 a barrel on the New York Mercantile Exchange floor on Wednesday, a NYMEX spokesman said.

Some market watchers questioned the validity of the trade as electronic trading in the February light sweet crude oil futures contract CLG8 was not near the $100 level when the floor trade occurred.

"It's some floor guy's 15 minutes of fame before they go the way of the dodo bird," said one NYMEX trader dismissively.

A single 1,000 barrel lot of February crude futures traded at $100 at 12:09 p.m. EST (1729 GMT). A trade one minute earlier at $100 was canceled by the exchange, according to Reuters data.

The bulk of trading in NYMEX energy futures has shifted away from the trading floor to an electronic market hosted on the Chicago Mercantile Exchange's CME.N Globex system.

The dwindling liquidity on the NYMEX trading floor has led to considerable speculation that the exchange will soon follow the lead of the InterContinenal Exchange (ICE.N), its energy futures main rival, and shut down the trading floor to cut costs. (Additional reporting by Janet McGurty; editing by Jim Marshall)