Arphaxad

son of Shem, born the year after the Deluge. He died at the age of 438 years (Gen 11:10-13; 1Chr 1:17; 1:18; Luke 3:36). He dwelt in Mesopotamia, and became, according to the Jewish historian Josephus, the progenitor of the Chaldeans. The tendency is to recognize in the word the name of the country nearest the ancient domain of the Chaldeans. Some regard the word as an Egypticized form of the territorial name of Ur Kasdim, or Ur of the Chaldees.

EBD - Easton's Bible Dictionary