U.S. stocks opened lower on Monday as investor concerns were fueled by oil prices hitting a fresh record high, marching closer to $50 a barrel, on supply concerns emerging from Nigeria. The Dow Jones industrial average <.DJI> was down 24.19 points, or 0.24 percent, at 10,023.05. The Standard & Poor's 500 Index <.SPX> was down 2.31 points, or 0.21 percent, at 1,107.80. The technology-laced Nasdaq Composite Index <.IXIC> was down 9.38 points, or 0.50 percent, at 1,870.10.|||