
    Timothy R. ASHLEY, in his individual capacity, Defendant-Appellant, v. Drupatty JAIPERSAUD, Plaintiff-Appellee.
    No. 12-15149
    Non-Argument Calendar.
    United States Court of Appeals, Eleventh Circuit.
    Oct. 22, 2013.
    
      William J. Atkins, Atkins & Fife, LLC, Albert Wan, Law Office of Albert Wan, Atlanta, GA, for Plaintiff-Appellee.
    Theodore Freeman, Brian Richard Dempsey, Freeman Mathis & Gary, LLP, Atlanta, GA, Kendrick McWilliams, Larry G. Cobb & Associates, Alpharetta, GA, for Defendant-Appellant.
    Before HULL, JORDAN and BLACK, Circuit Judges.
   PER CURIAM:

Timothy Ashley appeals (1) the denial of his motion for summary judgment on qualified immunity, and (2) the granting of plaintiff Drupatty Jaipersaud’s partial motion for summary judgment on the issue of liability. We affirm.

Ashley, a police detective, arrested Jaip-ersaud at the gas station Jaipersaud owned and operated. Jaipersaud subsequently sued Ashley under 42 U.S.C. § 1983, alleging Ashley violated her Fourth Amendment rights by arresting her without probable cause. Ashley claimed qualified immunity and moved for summary judgment. In turn, Jaipersaud moved for partial summary judgment on the issue of liability.

The district court denied Ashley’s motion and granted Jaipersaud’s motion for partial summary judgment. Denying Ashley qualified immunity, the court reasoned that based on the undisputed facts Ashley had neither probable cause nor even arguable probable cause to arrest Jaipersaud for any offense. The court then awarded Jaipersaud partial summary judgment on the issue of liability. Consistent with its ruling on qualified immunity, the court concluded that the same undisputed facts showed Ashley did not have probable cause to arrest Jaipersaud, and thus her arrest was unconstitutional. After a trial on the question of damages, Ashley appealed.

On appeal, Ashley presents two challenges. First, he claims the district court erred in denying him qualified immunity. Second, he claims the district court erred in granting Jaipersaud partial summary judgment on the issue of liability. Neither claim is properly before this Court, however. See, e.g., Hurley v. Moore, 233 F.3d 1295, 1297 (11th Cir.2000).

As a threshold matter, Ashley did not sufficiently deny Jaipersaud’s factual allegations in a responsive pleading, and has therefore admitted those facts. See Sinclair Ref. Co. v. Howell, 222 F.2d 637, 639 (5th Cir.1955) (holding that, by failing expressly to deny an allegation, the defendant admitted that allegation). Under Federal Rule Civil Procedure 8(b), parties “must ... admit or deny the allegations asserted against it by an opposing party.” See Fed.R.Civ.P. 8(b)(1). When, as here, a responsive pleading is required and an “allegation is not denied,” — i.e., the party does not “fairly respond to the substance of the allegation” — such allegation “is admitted.” See Fed.R.Civ.P. 8(b)(2) & (6); see also Burlington N.R. Co. v. Huddleston, 94 F.3d 1413, 1415 (10th Cir.1996) (“By failing to submit an answer ... denying the factual allegations of Plaintiffs complaint, Defendant admitted those allegations, thus placing no further burden upon Plaintiff to prove its case factually”).

Ashley never filed an answer to Jaiper-saud’s amended complaint. This was so even after the district court informed him of this omission, and even after the court and opposing counsel allowed him to file an answer out of time. Despite assuring the court and opposing counsel he would do so, Ashley still failed to file any document that satisfied Rule 8(b)’s requirements. See, e.g., Williams v. Calderon, 52 F.3d 1465, 1483 (9th Cir.1995) (noting that Rule 8(b) “require[s] fact-by-fact responses”). Accordingly, Ashley has admitted the veracity of Jaipersaud’s factual allegations and is bound by those admissions on appeal. See Cooper v. Meridian Yachts, Ltd., 575 F.3d 1151, 1177-78 (11th Cir.2009) (noting that parties are generally “bound by the admissions in [their] pleadings” and cannot contest such “judicially admitted” facts on appeal (internal quotation marks omitted)).

Moreover, Ashley did not sufficiently present his current legal arguments and theories to the district court. Regarding qualified immunity, Ashley asserts on appeal that he is immune from suit because he had arguable probable cause to arrest Jaipersaud. But Ashley’s theory of qualified immunity in the district court focused on actual probable cause. See, e.g., Skop v. City of Atlanta, 485 F.3d 1130, 1137-38 (11th Cir.2007) (discussing the legal differences between arguable probable cause and actual probable cause).

By shifting his theory of qualified immunity from actual to arguable probable cause, Ashley impermissibly attempts to “argue a different case from the” one he “presented to the district court.” See Irving v. Mazda Motor Corp., 136 F.3d 764, 769 (11th Cir.1998). The law is clear on such matters: “ ‘theories not raised squarely in the district court cannot be surfaced for the first time on appeal.’ ” Wood v. Milyard, — U.S. —, 132 S.Ct. 1826, 1832, 182 L.Ed.2d 733 (2012) (quoting McCoy v. Mass. Inst. of Tech., 950 F.2d 13, 22 (1st Cir.1991)). Since Ashley did not “specifically and clearly” articulate his current theory of qualified immunity to the district court, we will not address its merits on appeal. See Access Now, Inc. v. Sw. Airlines Co., 385 F.3d 1324, 1330-31 (11th Cir.2004).

We similarly decline to address Ashley’s challenge to liability. As with his qualified-immunity claim, Ashley’s arguments on appeal differ materially from those he presented to the district court. Before the district court, Ashley contended he was not liable because he had probable cause to arrest Jaipersaud “as a result of the obstructive behavior she demonstrated during the course of [his] investigation.” On appeal, however, Ashley contends he had probable cause before he even spoke with Jaipersaud — that is, before she even had a chance to obstruct his investigation.

Once again, Ashley is arguing a different case from the one he presented to the district court. See Irving, 136 F.3d at 769. And even if this is not a jurisdictional bar to review, see Dean Witter Reynolds, Inc. v. Fernandez, 741 F.2d 355, 360 (11th Cir.1984), Ashley’s case does not implicate the “exceptional conditions” that justify review of newly raised issues, see Access Now, 385 F.3d at 1332-35 & n. 4. Because Ashley did not squarely raise his current theory of probable cause in the district court, we decline to address its merits on appeal. See FDIC v. Verex Assurance, Inc., 3 F.3d 391, 395 (11th Cir.1993) (“[Ajppellate courts generally will not consider an issue or theory that was not raised in the district court”).

In sum, neither of Ashley’s claims is properly before this Court. The district court’s order denying Ashley’s motion for summary judgment and granting Jaiper-saud’s motion for partial summary judgment is AFFIRMED. 
      
      . We review motions for summary judgment de novo. Browning v. Peyton, 918 F.2d 1516, 1520 (11th Cir.1990). In light of our disposition of this case, we deny Jaipersaud’s motion to dismiss this appeal as moot.
     
      
      . In Bonner v. City of Prichard, 661 F.2d 1206, 1209 (11th Cir.1981) (en banc), this Court adopted as binding precedent all decisions of the former Fifth Circuit handed down prior to the close of business on September 30, 1981.
     
      
      . Although Ashley answered Jaipersaud’s initial complaint, "an amended complaint supersedes the initial complaint and becomes the operative pleading in the case.” Lowery v. Ala. Power Co., 483 F.3d 1184, 1219 (11th Cir.2007). Hence, because Ashley has not answered the operative pleading, he has failed to deny Jaipersaud’s factual allegations. See Fed.R.Civ.P. 8(b); see also Sinclair Ref. Co. v. Howell, 222 F.2d 637, 639 (5th Cir.1955).
     
      
      . Indeed, Ashley’s motion for summary judgment mentioned arguable probable cause only in passing and without any reasoned elaboration. Such glancing, unsupported references, however, are not sufficient to preserve arguments on appeal. See, e.g., Zhou Hua Zhu v. U.S. Att’y Gen., 703 F.3d 1303, 1316 n. 3 (11th Cir.2013).
     