CINCINNATI -- He was known as The Cobra. Dave Parker was an intimidating force when he wielded that 37-ounce bat during the 1970s and '80s for six Major League teams, including the Pirates and Reds.
The taxon of aquatic animals is a taxon. A clade is a monophyletic taxon or monophyletic group if you prefer. A monophyletic taxon (or a clade) is defined as a taxon that contains only all descendants of a common ancestor and the common ancestor.
Cladistics, also known as phylogenetic systematics, is a relatively new way of doing systematics. It works by analysing different taxa to find objective similarities and differences between them, and using those similarities and differences to derive a hierarchical structure showing which taxa are most similar to others.