Ctenophora

In 1829, the Estonian-German naturalist Johann Friedrich von Eschscholtz named a phylum of sea creatures after the most visible feature of their anatomy. He chose two Greek roots: kteis, meaning comb, and phoros, meaning bearing. The compound Ctenophora described exactly what he saw: rows of tiny comb-like plates made of fused cilia running in eight columns down the animal's sides. It was naming as pure description.

The Greek kteis had a long history before Eschscholtz borrowed it. Homer used the word for actual combs. In medical texts by Hippocrates and Galen, kteis named comb-shaped anatomical structures throughout the body. The root connects to an Indo-European ancestor related to combing and ordering, the same family as the Latin pecten, a comb-shaped structure found in the eyes of birds and reptiles.

When light hits the ctenophore's comb rows, called ctenes, it diffracts into iridescent bands that move in visible waves down the animal's flanks. This is a physical effect: refraction, not bioluminescence. Eschscholtz observed this in 1815 during Otto von Kotzebue's circumnavigation of the globe, working with specimens in buckets aboard a sailing ship. He published his formal taxonomy fourteen years later from his professorship at the University of Dorpat, now Tartu, Estonia.

Ctenophores have since placed themselves at the center of a sharp dispute in evolutionary biology. Some analyses since 2008 suggest ctenophores are the earliest-branching animal lineage, diverging before sponges, which would make their nervous systems an independent invention rather than an inheritance. Other analyses disagree. The name Eschscholtz chose for their combs turned out to label creatures whose evolutionary position is among the most contested in all of zoology.