The rank insignia used by the Martian Navy is inconsistent. In Remember the Cant (2015) the CO of the MCRN Donnager carries the rank of captain and has three chevrons (like the US military rank of sergeant) on her shoulder bars. Lopez, her XO, is a lieutenant and has two chevrons (like a corporal) on his shoulders. In this episode the XO of the MCRN Scirocco, Sutton, is also a lieutenant but he has three chevrons on his shoulder like Captain Yao.