1. 须鲸亚目：现生种的分类系统中,将鲸目分成两个亚目,须鲸亚目(Mysticeti)和齿鲸亚目(Odontoceti),是根据须鲸板和牙齿的有无来区分. 然而,还有其他不同的地方,即头骨的形状、气孔的型态以及肋骨、胸骨的型态. (表一)在陆生哺乳类的肋骨通常有两个关节突,
2. 须鲸 须鲸亚目：Mystacoceti 须鲸亚目 | Mysticeti 须鲸 须鲸亚目 | Mystoxformula 麦斯脱配方
1. The sperm whales in Odontoceti was closely related with baleen whales in Mysticeti, and then clustered with Delphinoidea and then with Ziphioidea.
其中抹香鲸总科与须鲸亚目聚合在一起，然后与海豚总科聚合再与喙鲸总科相聚。
2. NJ cluster analysis indicated that subclass Mysticeti is a monophyly whereas subclass Odontoceti is a polyphyly, including Delphinoidea, Physeteroidea, Ziphioidea and Platanistoidea.
NJ聚类分析结果与目前的主流观点基本相同，即须鲸亚目形成单系群而齿鲸亚目则为多系群，后者包括海豚总科、抹香鲸总科、喙鲸总科和淡水豚总科。
3. In addition, molecular biological techniques have been applied to address phylogenetic relationships among families within the suborder Mysticeti or Odontoceti, and within families, especially within the families Delphinidae and Phocoenidae, and river dolphins.
此外，分子生物学技术还被用于解决须鲸亚目和齿鲸亚目内科间以及科内种间的系统发生关系，特别是齿鲸亚目的海豚科、鼠豚科和淡水豚类。