Thureophoroi

Or thyreophoroi, Hellenistic foot armed with an oval shield of Celtic origin called the thureos or thyreos. Classed as Ax(S) in DBM (or Ax (I) for a few unmotivated militia types). Many people find the classification problematic.

See http://www.ne.jp/asahi/luke/ueda-sarson/Iphikrates2.html for one approach, leading to the suggestion that they be classed as "all Reg Sp (I) or, if acting as euzonoi, all Reg Ax (O)".

See http://www.antiquemilitaryhistory.com/illyriagallery.htm for a good ancient illustration of a thyreophoros, a grave monument from the Greek city of Apollonia in Illyria.