Larry Noble Mays appeals pro se from the district court’s judgment dismissing without prejudice his 42 U.S.C. § 1988 action for failure to prosecute. We have jurisdiction under 28 U.S.C. § 1291. We review for abuse of discretion, Ash v. Cvetkov, 739 F.2d 493, 495 (9th Cir. 1984), and we affirm.

Because Mays does not raise any arguments regarding the district court’s basis for dismissal, he waives any such challenge on appeal. See Greenwood v. FAA, 28 F.3d 971, 977 (9th Cir. 1994) (“We review only issues which are argued specifically and distinctly in a party’s opening brief. We will not manufacture arguments for an appellant ....”) (internal citation omitted). Mays’s contentions regarding the merits of his underlying claims are unavailing. See Al-Torki v. Kaempen, 78 F.3d 1381, 1385 (9th Cir. 1996) (stating that a dismissal for failure to prosecute “prevents disposition on the merits”).

AFFIRMED.