Kelvin Stanley Geoghagan, Louisiana prisoner # 307711, the plaintiff in the instant 42 U.S.C. § 1983 action, has appealed from the magistrate judge’s denial of his motions for appointment of counsel to represent him in the district court proceedings and from the district court’s failure to appoint counsel sua sponte at trial. *437 He also moves this court for the appointment of counsel.

If necessary, this court must examine the basis of its jurisdiction on its own motion. Mosley v. Cozby, 813 F.2d 659, 660 (5th Cir. 1987). Geoghagan did not challenge the magistrate judge’s adverse rulings before the district court, and there is no evidence in the record that Geogha-gan consented to proceed before the magistrate judge pursuant to 28 U.S.C. § 636(c)(1). Consequently, we lack jurisdiction to consider the magistrate judge’s ruling. See Gregg v. Linder, 349 F.3d 860, 862 (5th Cir. 2003).

Geoghagan also challenges the district court’s failure to appoint counsel sua sponte at trial. A district court may appoint counsel in a § 1983 case if exceptional circumstances exist. Branch v. Cole, 686 F.2d 264, 266 (5th Cir. 1982). We review a district court’s decision not to appoint counsel in a § 1983 action for abuse of discretion. Norton v. Dimazana, 122 F.3d 286, 293 (5th Cir. 1997). Geoghagan has not shown that the district court abused its discretion in failing to appoint counsel sua sponte. The judgment of the district court is AFFIRMED. In light of the foregoing, Geoghagan’s motion for appointment of appellate counsel is DENIED.