Main diagnostic markers identified by peptide mass fingerprinting in Balaenidae (North Pacific (NP) right, North Atlantic (NA) right and bowhead whales), Balaenopteridae (Bryde’s, sei, blue, minke, fin and humpback whales), and Eschrichtiidae (gray whale).

In gray and black are peaks found across families (in gray: all families and in black: Balaenopteridae and Eschrichtiidae), in green are balaenidae-only peaks (darker shade of green represents the right whales, and darkest green is for species-specific peaks), in blue are balaenopteridae-only peaks (darker shade of blue represents species-specific peaks), and in red are the eschrichtiidae-specific peaks. The—sign indicates the presence of a peak with relative intensity < 1%.