Madvig notes that Judges 1:13 calls Othniel Caleb’s “younger brother” (c.f. Judg. 3:9), but given that their father’s names were explicitly mentioned, this most likely refers to a younger relative. Madvig, Donald. Joshua. In F. E. Gaebelein (Ed.), The Expositor’s Bible Commentary, Volume 3: Deuteronomy, Joshua, Judges, Ruth, 1 & 2 Samuel (F. E. Gaebelein, Ed.). Grand Rapids, MI: Zondervan Publishing House. 199(2) 328.