Polychaete hypothesis

Polychaete hypothesis, theory that conodonts (minute toothlike structures found as fossils in marine rocks) are parts of the jaw apparatus of polychaete worms, a class of the annelid, or segmented, worms. Conodonts resemble the jaws (scolecodonts) of polychaete worms in form, and they are found in left and right pairs, as are scolecodonts. Polychaete teeth are known as early as the Ordovician period (about 505 million to 438 million years ago), but conodonts have their...